Journal articles: 'Body axis formation'

1

Bénazéraf, Bertrand, and Olivier Pourquié. "Formation and Segmentation of the Vertebrate Body Axis." Annual Review of Cell and Developmental Biology 29, no. 1 (October 6, 2013): 1–26. http://dx.doi.org/10.1146/annurev-cellbio-101011-155703.

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Takebayashi-Suzuki, Kimiko, and Atsushi Suzuki. "Intracellular Communication among Morphogen Signaling Pathways during Vertebrate Body Plan Formation." Genes 11, no. 3 (March 24, 2020): 341. http://dx.doi.org/10.3390/genes11030341.

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During embryonic development in vertebrates, morphogens play an important role in cell fate determination and morphogenesis. Bone morphogenetic proteins (BMPs) belonging to the transforming growth factor-β (TGF-β) family control the dorsal–ventral (DV) patterning of embryos, whereas other morphogens such as fibroblast growth factor (FGF), Wnt family members, and retinoic acid (RA) regulate the formation of the anterior–posterior (AP) axis. Activation of morphogen signaling results in changes in the expression of target genes including transcription factors that direct cell fate along the body axes. To ensure the correct establishment of the body plan, the processes of DV and AP axis formation must be linked and coordinately regulated by a fine-tuning of morphogen signaling. In this review, we focus on the interplay of various intracellular regulatory mechanisms and discuss how communication among morphogen signaling pathways modulates body axis formation in vertebrate embryos.

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Mongera, Alessandro, Arthur Michaut, Charlène Guillot, Fengzhu Xiong, and Olivier Pourquié. "Mechanics of Anteroposterior Axis Formation in Vertebrates." Annual Review of Cell and Developmental Biology 35, no. 1 (October 6, 2019): 259–83. http://dx.doi.org/10.1146/annurev-cellbio-100818-125436.

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The vertebrate anteroposterior axis forms through elongation of multiple tissues during embryogenesis. This process is based on tissue-autonomous mechanisms of force generation and intertissue mechanical coupling whose failure leads to severe developmental anomalies such as body truncation and spina bifida. Similar to other morphogenetic modules, anteroposterior body extension requires both the rearrangement of existing materials—such as cells and extracellular matrix—and the local addition of new materials, i.e., anisotropic growth, through cell proliferation, cell growth, and matrix deposition. Numerous signaling pathways coordinate body axis formation via regulation of cell behavior during tissue rearrangements and/or volumetric growth. From a physical perspective, morphogenesis depends on both cell-generated forces and tissue material properties. As the spatiotemporal variation of these mechanical parameters has recently been explored in the context of vertebrate body elongation, the study of this process is likely to shed light on the cross talk between signaling and mechanics during morphogenesis.

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Loucks, Evyn J., and Sara C. Ahlgren. "Disruption of normal body axis formation after teratogen exposure." Developmental Biology 306, no. 1 (June 2007): 409. http://dx.doi.org/10.1016/j.ydbio.2007.03.628.

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Ueda, Minako, and Frédéric Berger. "New cues for body axis formation in plant embryos." Current Opinion in Plant Biology 47 (February 2019): 16–21. http://dx.doi.org/10.1016/j.pbi.2018.08.005.

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Savard, Pierre. "Body axis determination during early development in amphibians." Biochemistry and Cell Biology 70, no. 10-11 (October 1, 1992): 875–91. http://dx.doi.org/10.1139/o92-136.

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The specification of the main axes of the body is a phenomenon based on cell communication and is among the early crucial events of embryonic development. Upon fertilization, the amphibian egg reorganizes its cytoplasmic content, leading to the establishment of the future dorsal–ventral axis of the body. Heterogeneous distribution of maternal components confers cellular regionalization after only a few mitoses. Development up to the 4000-cell stage proceeds almost entirely on maternal materials, and during this period there is remodeling of the chromatin to set up specific gene expression in various regions of the embryo. The zygote at this stage has already undertaken cellular interactions leading to mesoderm formation and regionalization. Dorsal mesodermal components then induce the formation of the Spemann's organizer, a structure directly involved in the specification of the anterior–posterior axis of the embryo (head to tail). Molecular analysis of these phenomena has allowed the identification of growth-factor-like and transcription-factor-like proteins that have characteristics typical of specification factors. We will review the recent advances on these molecules and will also discuss the putative role of retinoic acid as a posteriorizing agent.Key words: chromatin remodeling, cellular regionalization, homeobox, inducing factor, retinoic acid.

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Yan, Lu, Jing Chen, Xuechen Zhu, Jiawei Sun, Xiaotong Wu, Weimin Shen, Weiying Zhang, Qinghua Tao, and Anming Meng. "Maternal Huluwa dictates the embryonic body axis through β-catenin in vertebrates." Science 362, no. 6417 (November 22, 2018): eaat1045. http://dx.doi.org/10.1126/science.aat1045.

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The vertebrate body is formed by cell movements and shape change during embryogenesis. It remains undetermined which maternal signals govern the formation of the dorsal organizer and the body axis. We found that maternal depletion of huluwa, a previously unnamed gene, causes loss of the dorsal organizer, the head, and the body axis in zebrafish and Xenopus embryos. Huluwa protein is found on the plasma membrane of blastomeres in the future dorsal region in early zebrafish blastulas. Huluwa has strong dorsalizing and secondary axis–inducing activities, which require β-catenin but can function independent of Wnt ligand/receptor signaling. Mechanistically, Huluwa binds to and promotes the tankyrase-mediated degradation of Axin. Therefore, maternal Huluwa is an essential determinant of the dorsal organizer and body axis in vertebrate embryos.

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TILTON, F., J. LADU, M. VUE, N. ALZARBAN, and R. TANGUAY. "Dithiocarbamates have a common toxic effect on zebrafish body axis formation." Toxicology and Applied Pharmacology 216, no. 1 (October 1, 2006): 55–68. http://dx.doi.org/10.1016/j.taap.2006.04.014.

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Hahn, M., and H. Jäckle. "Drosophila goosecoid participates in neural development but not in body axis formation." EMBO Journal 15, no. 12 (June 1996): 3077–84. http://dx.doi.org/10.1002/j.1460-2075.1996.tb00670.x.

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Fan, M. J., and S. Y. Sokol. "A role for Siamois in Spemann organizer formation." Development 124, no. 13 (July 1, 1997): 2581–89. http://dx.doi.org/10.1242/dev.124.13.2581.

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The vertebrate body plan is specified in the early embryo through the inductive influence of the organizer, a special region that forms on the dorsalmost side of the embryo at the beginning of gastrulation. In Xenopus, the homeobox gene Siamois is activated prior to gastrulation in the area of organizer activity and is capable of inducing a secondary body axis when ectopically expressed. To elucidate the function of endogeneous Siamois in dorsoventral axis formation, we made a dominant repressor construct (SE) in which the Siamois homeodomain was fused to an active repression domain of Drosophila engrailed. Overexpression of 1–5 pg of this chimeric mRNA in the early embryo blocks axis development and inhibits activation of dorsal, but not ventrolateral, marginal zone markers. At similar expression levels, SE proteins with altered DNA-binding specificity do not have the same effect. Coexpression of mRNA encoding wild-type Siamois, but not a mutated Siamois, restores dorsal development to SE embryos. Furthermore, SE strongly blocks axis formation triggered by beta-catenin but not by the organizer product noggin. These results suggest that Siamois function is essential for beta-catenin-mediated formation of the Spemann organizer, and that Siamois acts prior to noggin in specifying dorsal development.

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Clavel, Manuel, and Pablo Clavel. "Occipital neuralgia secondary to exuberant callus formation." Journal of Neurosurgery 85, no. 6 (December 1996): 1170–71. http://dx.doi.org/10.3171/jns.1996.85.6.1170.

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✓ The authors report the case of a 78-year-old woman suffering from right occipital neuralgia in whom computerized tomography and magnetic resonance images demonstrated an irregular bone mass in the C-2 vertebral body. This “bone tumor” happened to be an exuberant callus formation that arose as a result of a previous axis body fracture. The patient's occipital pain was immediately relieved after she underwent C2–3 root release.

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Du, Xiao Li, Hong Wei Song, and Jie Chen. "Laws of Formation and Evolution of Pressure Arch in Coal Mining Adjoining Rock." Advanced Materials Research 243-249 (May 2011): 2596–600. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2596.

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Based on numerical simulation of computing Software ANSYS, the curve of arching coefficient variation of pressure arch due to actual mining was analyzed aiming to a special mining face, the law of stress transfer and change in surrounding rock was discussed, and the evolving features and characteristics of pressure arch was obtained. The analysis and discussion show the following facts: Arch body will become thicker and stress in the arch body increases with working face’s driving distance increasing; the morphology of pressure arch transits from ellipsoid with long axis in the vertical direction to ellipsoid with long axis in the horizontal direction along the trend of working face; along the tendency of working face, the morphology of pressure arch is a ellipsoid with long axis in the vertical direction.

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Bono, Shinji, Yuji Maruyama, and Yuka Tabe. "Formation and dynamics of the aggregates of cholesteric double-twist cylinders." Soft Matter 14, no. 48 (2018): 9798–805. http://dx.doi.org/10.1039/c8sm01565a.

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Chi, Shihong, and Xiaoming Tang. "Stoneley-wave speed modeling in general anisotropic formations." GEOPHYSICS 71, no. 4 (July 2006): F67—F77. http://dx.doi.org/10.1190/1.2216928.

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For determining anisotropy using acoustic logging data, Stoneley waves are the only wave modes that are sensitive to formation properties transverse to the borehole axis. We derive Stoneley-wave speeds in deviated and horizontal wells penetrating anisotropic formations. We first apply the elastic theory of an anisotropic body to find the radial displacement of a borehole cross section under uniform pressure. We then derive the effective formation modulus based on quasistatic analysis. Finally, we derive a two-dimensional analytical solution for low-frequency Stoneley-wave speed in a horizontal well penetrating a transversely isotropic formation with a vertical symmetry axis. For deviated wells, we derive a 3D analytical solution that is also valid for general anisotropic formations. Our analytic solutions agree with the finite-difference modeling results and are particularly suited for strongly anisotropic formations. With increasing well deviation the sensitivity of Stoneley-wave speed to horizontal shear-wave velocity decreases and the sensitivity to vertical shear-wave velocity increases.

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Di Mambro, Riccardo, Sabrina Sabatini, and Raffaele Dello Ioio. "Patterning the Axes: A Lesson from the Root." Plants 8, no. 1 (December 31, 2018): 8. http://dx.doi.org/10.3390/plants8010008.

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How the body plan is established and maintained in multicellular organisms is a central question in developmental biology. Thanks to its simple and symmetric structure, the root represents a powerful tool to study the molecular mechanisms underlying the establishment and maintenance of developmental axes. Plant roots show two main axes along which cells pass through different developmental stages and acquire different fates: the root proximodistal axis spans longitudinally from the hypocotyl junction (proximal) to the root tip (distal), whereas the radial axis spans transversely from the vasculature tissue (centre) to the epidermis (outer). Both axes are generated by stereotypical divisions occurring during embryogenesis and are maintained post-embryonically. Here, we review the latest scientific advances on how the correct formation of root proximodistal and radial axes is achieved.

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McKernan, Stuart, D. René Rasmussen, and C. Barry Carter. "The determination of the rigid-body translation across anti-phase boundaries in GaAs." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 362–63. http://dx.doi.org/10.1017/s0424820100174941.

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The growth of a polar material on a non-polar substrate leads to the possibility of anti-phase boundary (APB) formation. Across the boundary there will be bonding between like atoms. The stoichiometry of the material may, or may not, be affected, depending on the relative proportion of A-A and B-B bonds in the boundary. This will depend on the crystallographic orientation of the boundary plane. Because of the different nature of the bonding at an APB, it has been assumed that the physical properties, particularly the electrical characteristics, of the polar layer will be adversely affected by the presence of APBs. Much effort has therefore gone into the development of growth conditions which minimize the likelihood of APB formation, particularly in the GaAs on Si system.Little work, however, has been done on the fine-structure of the APB itself. In this paper the results of a quantitative comparison of the α fringes produced in 2-beam images of APBs, with calculated images will be presented. The theoretical images were calculated using the COMIS program, which uses a manybeam formalism based on the Howie-Whelan equation. The samples were prepared from GaAs epilayers deposited on a (100) Ge substrate. The Ge substrate was removed by mechanical polishing prior to ion milling of the epilayer in a liquid nitrogen cooled specimen stage. The epilayer was examined at a number of low index zone axes, using a number of different 2-beam conditions. A representative selection is shown in figure 1. Images A, B, and C, were obtained close to the [001] zone axis, image D was obtained near the [101] zone axis and shows the horizontal APB nearly flat-on, but out of contrast. Near the [101] zone axis this APB appears as a line defect, and therefore must lie on the (101) plane.

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Kwok, Yue‐Kuen, and Larry A. Beyer. "Gravity due to a body with rotational symmetry about a vertical axis." GEOPHYSICS 58, no. 2 (February 1993): 298–306. http://dx.doi.org/10.1190/1.1443414.

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Mass distributions encountered in gravity modeling are sometimes approximately symmetrical about a vertical axis. Examples include salt domes and other types of piercement structures, fluid behavior surrounding an injection or pumping well, formation damage and mudcake surrounding a drillhole, natural impact craters, human induced craters and underground explosions, and some volcanic and intrusive structures. Occasionally, gravity surveys are conducted in boreholes or vertical shafts that may or may not coincide with the axis of symmetry. The formulations presented here are useful for the interpretation of such gravity surveys.

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McMenamin, Mark A. S., Stephen M. Rowland, Frank Corsetti, Anne M. Dix, and Ronald P. Nance. "Vendian body fossils (?) and isotope stratigraphy from the Caborca area, Sonora, Mexico." Paleontological Society Special Publications 6 (1992): 206. http://dx.doi.org/10.1017/s2475262200007668.

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In the Proterozoic Clemente Formation at Cerro Rajon, south of Caborca, Sonora, we have collected sandstone beds that contain many small, sediment-filled structures. Each structure is a thin-walled, elongate sack, about 1.5 cm tall, oriented perpendicular to bedding. The sacklike structures are laterally flattened and roughly elliptical in transverse section, with the major axis of the ellipse measuring several mm and the minor axis 2-3 mm. The walls are not mineralized and consist of a thin layer of cryptocrystalline clay. One or both walls of each specimen is undulatory with a wavelength of 3-4 mm. The sacks are closed at the bottom, but appear to be open at the top, like an uninflated toy balloon. On the bottom surface of the sandstone bed, beneath each vertical sack structure, is a prolate ellipsoid-shaped sole mark. The long axis of each ellipsoid sole mark is parallel to the long axis of the associated sack structure, and the sole marks are oriented sub-parallel to one another on the surface of the bed. We tentatively interpret these structures to be the holdfasts of gregarious, attached, benthic organisms oriented sub-parallel to one another on the sea floor.A preliminary study of carbon and oxygen isotope stratigraphy was carried out on the 2 km-thick Proterozoic through Lower Cambrian section at Cerro Rajon. Samples were collected every 50 m, and analyses were done in the laboratory of J.M. Hayes at Indiana University, whose assistance is gratefully acknowledged. The isotope record shows a primary signature for most of the section. Although the wide spacing of sample collection does not permit an unequivocal intercontinental correlation, a prominent negative δ13C excursion near the base of the Papalote Formation may correlate with similar excursions at the Vendian-Cambrian boundary on several continents. This would place the base of the Cambrian of the Caborca area several hundred meters lower than previously thought, but still several hundred meters above the possible body fossils of the Clemente Formation.

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Dell’Oro, A., J. Boccenti, F. Spoto, P. Paolicchi, and Z. Knežević. "The impact of physical processes on the estimation of the ages of asteroid families." Monthly Notices of the Royal Astronomical Society 506, no. 3 (July 9, 2021): 4302–20. http://dx.doi.org/10.1093/mnras/stab1947.

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ABSTRACT One of the methods used to estimate the ages of the asteroid families is based on the interpretation of the distribution of the sizes versus orbital semimajor axes of their members as the result of their post-formation dynamical evolution. The fundamental hypothesis is that the present distribution of the semimajor axes is essentially the product of the Yarkovsky effect. On the other hand, the observable features of the asteroid families can be affected by several physical and dynamical processes. In this paper, we discuss the role of: (1) the initial distribution of the ejection velocities at the time of the primordial break-up event; (2) the possible correlations between the family members ejection direction and the orientation of the rotational axis (which the direction of the Yarkovsky semimajor axis drift depends on); (3) the gravitational reaccumulation of the parent body fragments during the ballistic phase of the formation process; and (4) the collisional re-orientation of the spin axes during the post-formation evolution phase. We show how each of these mechanisms affects the determination of the ages of the asteroid families, and what additional information can be inferred regarding some aspects of the collisional evolution of the rotation axes.

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Samakovli, Despina, Tereza Tichá, Tereza Vavrdová, Natálie Závorková, Ales Pecinka, Miroslav Ovečka, and Jozef Šamaj. "HEAT SHOCK PROTEIN 90 proteins and YODA regulate main body axis formation during early embryogenesis." Plant Physiology 186, no. 3 (April 15, 2021): 1526–44. http://dx.doi.org/10.1093/plphys/kiab171.

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Abstract The YODA (YDA) kinase pathway is intimately associated with the control of Arabidopsis (Arabidopsis thaliana) embryo development, but little is known regarding its regulators. Using genetic analysis, HEAT SHOCK PROTEIN 90 (HSP90) proteins emerge as potent regulators of YDA in the process of embryo development and patterning. This study is focused on the characterization and quantification of early embryonal traits of single and double hsp90 and yda mutants. HSP90s genetic interactions with YDA affected the downstream signaling pathway to control the development of both basal and apical cell lineage of embryo. Our results demonstrate that the spatiotemporal expression of WUSCHEL-RELATED HOMEOBOX 8 (WOX8) and WOX2 is changed when function of HSP90s or YDA is impaired, suggesting their essential role in the cell fate determination and possible link to auxin signaling during early embryo development. Hence, HSP90s together with YDA signaling cascade affect transcriptional networks shaping the early embryo development.

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Plöger, Ruben, and Christoph Viebahn. "Expression patterns of signalling molecules and transcription factors in the early rabbit embryo and their significance for modelling amniote axis formation." Development Genes and Evolution 231, no. 3-4 (June 7, 2021): 73–83. http://dx.doi.org/10.1007/s00427-021-00677-w.

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AbstractThe anterior-posterior axis is a central element of the body plan and, during amniote gastrulation, forms through several transient domains with specific morphogenetic activities. In the chick, experimentally proven activity of signalling molecules and transcription factors lead to the concept of a ‘global positioning system’ for initial axis formation whereas in the (mammotypical) rabbit embryo, a series of morphological or molecular domains are part of a putative ‘three-anchor-point model’. Because circular expression patterns of genes involved in axis formation exist in both amniote groups prior to, and during, gastrulation and may thus be suited to reconcile these models, the expression patterns of selected genes known in the chick, namely the ones coding for the transcription factors eomes and tbx6, the signalling molecule wnt3 and the wnt inhibitor pkdcc, were analysed in the rabbit embryonic disc using in situ hybridisation and placing emphasis on their germ layer location. Peripheral wnt3 and eomes expression in all layers is found initially to be complementary to central pkdcc expression in the hypoblast during early axis formation. Pkdcc then appears — together with a posterior-anterior gradient in wnt3 and eomes domains — in the epiblast posteriorly before the emerging primitive streak is marked by pkdcc and tbx6 at its anterior and posterior extremities, respectively. Conserved circular expression patterns deduced from some of this data may point to shared mechanisms in amniote axis formation while the reshaping of localised gene expression patterns is discussed as part of the ‘three-anchor-point model’ for establishing the mammalian body plan.

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Rees, D. W. A. "Tensile flow and instability in galvanized, rolled steel sheet." Journal of Strain Analysis for Engineering Design 30, no. 4 (October 1, 1995): 305–15. http://dx.doi.org/10.1243/03093247v304305.

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This paper examines flow and instability of a zinc-clad sheet used for the manufacture of car panels. Three forming properties are reported from off-axis tensile testing: (a) anisotropy in the plane of the sheet, (b) tensile instability and (c) homogeneity of deformation. The analysis correlates the directional flow behaviour using the Hill yield function (1)† as a basis for equivalence. This function explains satisfactorily the linear plastic strain paths and the variation in r values observed but does contract flow behaviour to a single curve. A subtangent is derived for the off-axis testpiece in terms of its orientation and two strain ratios referred to its axis. This is used to derive the limiting uniform strain that is found to remain constant in regions exterior to local neck formation. A condition is established for which the principal axes of stress and plastic strain remain coincident. It is shown, from the measured rotations of the principal material axes, that deformations conform to standard strain transformation equations upon removal of rigid-body rotations.

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Shenk, M. A., H. R. Bode, and R. E. Steele. "Expression of Cnox-2, a HOM/HOX homeobox gene in hydra, is correlated with axial pattern formation." Development 117, no. 2 (February 1, 1993): 657–67. http://dx.doi.org/10.1242/dev.117.2.657.

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Cnox-2 is a HOM/HOX homeobox gene that we have identified in the simple metazoan Hydra vulgaris (Cnidaria: Hydrozoa). Cnox-2 is most closely related to anterior members of the Antennapedia gene complex from Drosophila, with the greatest similarity to Deformed. The Cnox-2 protein is expressed in the epithelial cells of adult hydra polyps in a region-specific pattern along the body axis, at a low level in the head and at a high level in the body column and the foot. The expression pattern of Cnox-2 is consistent with a role in axial pattern formation. Alteration of hydra axial patterning by treatment with diacylglycerol (DAG) results in an increase of head activation down the body column and in a coordinate reduction of Cnox-2 expression in epithelial cells in ‘head-like’ regions. These results suggest that Cnox-2 expression is negatively regulated by a signaling pathway acting through protein kinase C (PKC), and that the varying levels of expression of Cnox-2 along the body axis have the potential to result in differential gene expression which is important for hydra pattern formation.

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Yan, Lu, Jing Chen, Qinghua Tao, and Anming Meng. "Hulu, a novel transmembrane protein, is absolutely required for organizer and body axis formation in zebrafish." Mechanisms of Development 145 (July 2017): S6—S7. http://dx.doi.org/10.1016/j.mod.2017.04.535.

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Hatayama, Minoru, Katsuhiko Mikoshiba, and Jun Aruga. "IP3 signaling is required for cilia formation and left–right body axis determination in Xenopus embryos." Biochemical and Biophysical Research Communications 410, no. 3 (July 2011): 520–24. http://dx.doi.org/10.1016/j.bbrc.2011.06.014.

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Broun, Mariya, and Hans R. Bode. "Characterization of the head organizer in hydra." Development 129, no. 4 (February 15, 2002): 875–84. http://dx.doi.org/10.1242/dev.129.4.875.

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A central process in the maintenance of axial patterning in the adult hydra is the head activation gradient, i.e. the potential to form a secondary axis, which is maximal in the head and is graded down the body column. Earlier evidence suggested that this gradient was based on a single parameter. Using transplantation experiments, we provide evidence that the hypostome, the apical part of the head, has the characteristics of an organizer in that it has the capacity to induce host tissue to form most of the second axis. By contrast, tissue of the body column has a self-organizing capacity, but not an inductive capacity. That the inductive capacity is confined to the hypostome is supported by experiments involving a hypostome-contact graft. The hypostome, but not the body column, transmits a signal(s) leading to the formation of a second axis. In addition, variations of the transplantation grafts and hypostome-contact grafts provide evidence for several characteristics of the organizer. The inductive capacity of the head and the self-organizing capacity of the body column are based on different pathways. Head inhibition, yya signal produced in the head and transmitted to the body column to prevent head formation, represses the effect of the inducing signal by interfering with formation of the hypostome/organizer. These results indicate that the organizer characteristics of the hypostome of an adult hydra are similar to those of the organizer region of vertebrate embryos. They also indicate that the Gierer-Meinhardt model provides a reasonable framework for the mechanisms that underlie the organizer and its activities. In addition, the results suggest that a region of an embryo or adult with the characteristics of an organizer arose early in metazoan evolution.

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Kirillova, Anastasia, Grigory Genikhovich, Ekaterina Pukhlyakova, Adrien Demilly, Yulia Kraus, and Ulrich Technau. "Germ-layer commitment and axis formation in sea anemone embryonic cell aggregates." Proceedings of the National Academy of Sciences 115, no. 8 (February 9, 2018): 1813–18. http://dx.doi.org/10.1073/pnas.1711516115.

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Robust morphogenetic events are pivotal for animal embryogenesis. However, comparison of the modes of development of different members of a phylum suggests that the spectrum of developmental trajectories accessible for a species might be far broader than can be concluded from the observation of normal development. Here, by using a combination of microsurgery and transgenic reporter gene expression, we show that, facing a new developmental context, the aggregates of dissociated embryonic cells of the sea anemone Nematostella vectensis take an alternative developmental trajectory. The self-organizing aggregates rely on Wnt signals produced by the cells of the original blastopore lip organizer to form body axes but employ morphogenetic events typical for normal development of distantly related cnidarians to re-establish the germ layers. The reaggregated cells show enormous plasticity including the capacity of the ectodermal cells to convert into endoderm. Our results suggest that new developmental trajectories may evolve relatively easily when highly plastic embryonic cells face new constraints.

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Torres-Ruiz, R. A., and G. Jurgens. "Mutations in the FASS gene uncouple pattern formation and morphogenesis in Arabidopsis development." Development 120, no. 10 (October 1, 1994): 2967–78. http://dx.doi.org/10.1242/dev.120.10.2967.

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The pattern of cell division is very regular in Arabidopsis embryogenesis, enabling seedling structures to be traced back to groups of cells in the early embryo. Recessive mutations in the FASS gene alter the pattern of cell division from the zygote, without interfering with embryonic pattern formation: although no primordia of seedling structures can be recognised by morphological criteria at the early-heart stage, all elements of the body pattern are differentiated in the seedling. fass seedlings are strongly compressed in the apical-basal axis and enlarged circumferentially, notably in the hypocotyl. Depending on the width of the hypocotyl, fass seedlings may have up to three supernumerary cotyledons. fass mutants can develop into tiny adult plants with all parts, including floral organs, strongly compressed in their longitudinal axis. At the cellular level, fass mutations affect cell elongation and orientation of cell walls but do not interfere with cell polarity as evidenced by the unequal division of the zygote. The results suggest that the FASS gene is required for morphogenesis, i.e., oriented cell divisions and position-dependent cell shape changes generating body shape, but not for cell polarity which seems essential for pattern formation.

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Hammerschmidt, M., F. Pelegri, M. C. Mullins, D. A. Kane, M. Brand, F. J. van Eeden, M. Furutani-Seiki, et al. "Mutations affecting morphogenesis during gastrulation and tail formation in the zebrafish, Danio rerio." Development 123, no. 1 (December 1, 1996): 143–51. http://dx.doi.org/10.1242/dev.123.1.143.

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We have identified several genes that are required for various morphogenetic processes during gastrulation and tail formation. Two genes are required in the anterior region of the body axis: one eyed pinhead (oep) and dirty nose (dns).oep mutant embryos are defective in prechordal plate formation and the specification of anterior and ventral structures of the central nervous system. In dns mutants, cells of the prechordal plate, such as the prospective hatching gland cells, fail to specify. Two genes are required for convergence and extension movements. In mutant trilobite embryos, extension movements on the dorsal side of the embryo are affected, whereas in the formerly described spadetail mutants, for which two new alleles have been isolated, convergent movements of ventrolateral cells to the dorsal side are blocked. Two genes are required for the development of the posterior end of the body axis. In pipetail mutants, the tailbud fails to move ventrally on the yolk sac after germ ring closure, and the tip of the tail fails to detach from the yolk tube. Mutants in kugelig (kgg) do not form the yolk tube at the posterior side of the yolk sac.

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Carroll, S. B., G. M. Winslow, V. J. Twombly, and M. P. Scott. "Genes that control dorsoventral polarity affect gene expression along the anteroposterior axis of the Drosophila embryo." Development 99, no. 3 (March 1, 1987): 327–32. http://dx.doi.org/10.1242/dev.99.3.327.

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At least 13 genes control the establishment of dorsoventral polarity in the Drosophila embryo and more than 30 genes control the anteroposterior pattern of body segments. Each group of genes is thought to control pattern formation along one body axis, independently of the other group. We have used the expression of the fushi tarazu (ftz) segmentation gene as a positional marker to investigate the relationship between the dorsoventral and anteroposterior axes. The ftz gene is normally expressed in seven transverse stripes. Changes in the striped pattern in embryos mutant for other genes (or progeny of females homozygous for maternal-effect mutations) can reveal alterations of cell fate resulting from such mutations. We show that in the absence of any of ten maternal-effect dorsoventral polarity gene functions, the characteristic stripes of ftz protein are altered. Normally there is a difference between ftz stripe spacing on the dorsal and ventral sides of the embryo; in dorsalized mutant embryos the ftz stripes appear to be altered so that dorsal-type spacing occurs on all sides of the embryo. These results indicate that cells respond to dorsoventral positional information in establishing early patterns of gene expression along the anteroposterior axis and that there may be more significant interactions between the different axes of positional information than previously determined.

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MAZZITELLO, KARINA I., CONSTANCIO M. ARIZMENDI, ALVARO L. SALAS BRITO, and HILARY G. E. HENTSCHEL. "EMBRYONIC SOMITE FORMATION GENERATED BY GENETIC NETWORK OSCILLATIONS WITH NOISE." International Journal of Bifurcation and Chaos 20, no. 02 (February 2010): 341–47. http://dx.doi.org/10.1142/s021812741002579x.

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In most vertebrate species, the body axis is generated by the formation of repeated transient structures called somites. This spatial periodicity in somitogenesis has been related to the genetic network oscillations in certain mRNAs and their associated gene products in the cells forming the presomitic mesoderm. The current molecular view of the mechanism underlying these oscillations involves negative-feedback regulation at transcriptional and translational levels. The spatially periodic nature of somite formation suggests that the genetic network involved must display intracellular oscillations that interact with a longitudinal positional information gradient, called determination front, down the axis of vertebrate embryos to create this spatial patterning. Here, we consider a simple model for diploid cells based on this current biological picture considering gene regulation as a noisy process relevant in a real developmental situation and study its consequences for somitogenesis. Comparison is made with the known properties of somite formation in the zebrafish embryo.

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Suslov, Andrey V., Elizaveta Chairkina, Maria D. Shepetovskaya, Irina S. Suslova, Victoria A. Khotina, Tatiana V. Kirichenko, and Anton Y. Postnov. "The Neuroimmune Role of Intestinal Microbiota in the Pathogenesis of Cardiovascular Disease." Journal of Clinical Medicine 10, no. 9 (May 6, 2021): 1995. http://dx.doi.org/10.3390/jcm10091995.

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Currently, a bidirectional relationship between the gut microbiota and the nervous system, which is considered as microbiota-gut-brain axis, is being actively studied. This axis is believed to be a key mechanism in the formation of somatovisceral functions in the human body. The gut microbiota determines the level of activation of the hypothalamic–pituitary system. In particular, the intestinal microbiota is an important source of neuroimmune mediators in the pathogenesis of cardiovascular disease. This review reflects the current state of publications in PubMed and Scopus databases until December 2020 on the mechanisms of formation and participation of neuroimmune mediators associated with gut microbiota in the development of cardiovascular disease.

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Plickert, Günter, Vered Jacoby, Uri Frank, Werner A. Müller, and Ofer Mokady. "Wnt signaling in hydroid development: Formation of the primary body axis in embryogenesis and its subsequent patterning." Developmental Biology 298, no. 2 (October 2006): 368–78. http://dx.doi.org/10.1016/j.ydbio.2006.06.043.

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Indrianto, Ari, Ioulia Barinova, Alisher Touraev, and Erwin Heberle-Bors. "Tracking individual wheat microspores in vitro: identification of embryogenic microspores and body axis formation in the embryo." Planta 212, no. 2 (January 19, 2001): 163–74. http://dx.doi.org/10.1007/s004250000375.

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Chai, Ya Dong, Zi Zhen Liu, Daichi Noda, and Motohiro Tagaya. "Mild Reaction of Highly-Oriented Collagen Fibril Arrays with Simulated Body Fluid." Solid State Phenomena 324 (September 20, 2021): 166–72. http://dx.doi.org/10.4028/www.scientific.net/ssp.324.166.

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The highly-oriented collagen fibrils that paralleled to one (rubbing) direction were fabricated by which the collagen molecular solution was spin-coated and self-assembled on the rubbed polyimide film. Subsequently, the hydroxyapatite crystals were precipitated on the collagen fibrils by immersing into simulated body fluid. In details, the carboxyl groups on the collagen fibrils were used as a reaction field for adsorption of Ca2+ ions and promoted the formation of hydroxyapatite crystals. As a result, the hydroxyapatite crystals grew along the a-axis leading to the formation of stable interfaces between hydroxyapatite crystals and collagen fibrils. Moreover, the oriented collagen fibril arrays were more useful for the nucleation and growth of hydroxyapatite. Therefore, we successfully fabricated the highly-oriented collagen fibril arrays which were useful for the precipitation of hydroxyapatite crystals.

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Gimlich, Robert L. "Cytoplasmic localization and chordamesoderm induction in the frog embryo." Development 89, Supplement (November 1, 1985): 89–111. http://dx.doi.org/10.1242/dev.89.supplement.89.

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The experiments described here were designed to reveal the distribution in the frog early embryo of components which are sufficient for specification of the dorsal structures of the embryonic body axis. The approach was to allow cleavage planes to divide the embryo into various well-defined regions and to transplant cells from each region into recipient embryos which would otherwise fail to form axial structures. Partial or complete body axis development could then be scored by the use of external criteria or histological methods. Recipients were embryos which had been irradiated before first cleavage with ultraviolet light on the vegetal surface. Irradiated embryos display a well-characterized set of deficiencies in the dorsal structures of the body axis, but their development can be ‘rescued’ toward normalcy in several ways. In particular, transplantation of certain small groups of blastomeres from the normal 32- to 64-cell embryo into irradiated recipients was sufficient to cause partial or complete axis development. Cell groups which could cause rescue were located in the vegetal and equatorial levels of one quadrant of the normal embryo — the quadrant centered on the future dorsal midline. Clonal marking analysis showed that the vegetal-most cells of this quadrant contribute primarily to endodermal structures in normal development. In rescued recipient embryos, these cells also contributed only to the endoderm; the dorsal mesoderm and central nervous system were formed exclusively by host cells which originated near the transplant. Rescue could also result from transplantation of equatorial cells from the dorsal quadrant of the normal embryo. As in normal development, these cells formed primarily the chordamesoderm of the rescued embryo. Host cells were induced to contribute the somitic mesoderm, central nervous system, and other structures which would have been missing but for the presence of the transplanted cells. The frequency and degree of rescue caused by equatorial and vegetal transplants is variable. This was explained by the discovery that the location of components needed for rescue varies among individual embryos without regard to the positions of cleavage planes. This was true even when donor embryos were selected on the basis of a precisely regular pattern of cleavage. In such selected embryos, particular blastomeres make a predictable contribution of progeny to the body axis. Thus it may be that the positions of components which can cause axis formation vary without exact regard to the fate map of prospective areas. The implications of this for the study of cytoplasmic localization in the early embryo are discussed. In any case, it is likely that regional interactions and a degree of developmental autonomy in the area of the prospective chordamesoderm are both involved in formation of the dorsal structures of the embryonic body axis.

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Ye, Zhi, and David Kimelman. "Hox13 genes are required for mesoderm formation and axis elongation during early zebrafish development." Development 147, no. 22 (November 5, 2020): dev185298. http://dx.doi.org/10.1242/dev.185298.

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ABSTRACTThe early vertebrate embryo extends from anterior to posterior due to the addition of neural and mesodermal cells from a neuromesodermal progenitor (NMp) population located at the most posterior end of the embryo. In order to produce mesoderm throughout this time, the NMps produce their own niche, which is high in Wnt and low in retinoic acid. Using a loss-of-function approach, we demonstrate here that the two most abundant Hox13 genes in zebrafish have a novel role in providing robustness to the NMp niche by working in concert with the niche-establishing factor Brachyury to allow mesoderm formation. Mutants lacking both hoxa13b and hoxd13a in combination with reduced Brachyury activity have synergistic posterior body defects, in the strongest case producing embryos with severe mesodermal defects that phenocopy brachyury null mutants. Our results provide a new way of understanding the essential role of the Hox13 genes in early vertebrate development.This article has an associated ‘The people behind the papers’ interview.

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Gao, Yan, Qing Cao, Lei Lu, Xuena Zhang, Zan Zhang, Xiaohua Dong, Wenshuang Jia, and Ying Cao. "Kruppel-like factor family genes are expressed duringXenopusembryogenesis and involved in germ layer formation and body axis patterning." Developmental Dynamics 244, no. 10 (August 10, 2015): 1328–46. http://dx.doi.org/10.1002/dvdy.24310.

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Broun, M., S. Sokol, and H. R. Bode. "Cngsc, a homologue of goosecoid, participates in the patterning of the head, and is expressed in the organizer region of Hydra." Development 126, no. 23 (December 1, 1999): 5245–54. http://dx.doi.org/10.1242/dev.126.23.5245.

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We have isolated Cngsc, a hydra homologue of goosecoid gene. The homeodomain of Cngsc is identical to the vertebrate (65-72%) and Drosophila (70%) orthologues. When injected into the ventral side of an early Xenopus embryo, Cngsc induces a partial secondary axis. During head formation, Cngsc expression appears prior to, and directly above, the zone where the tentacles will emerge, but is not observed nearby when the single apical tentacle is formed. This observation indicates that the expression of the gene is not necessary for the formation of a tentacle per se. Rather, it may be involved in defining the border between the hypostome and the tentacle zone. When Cngsc(+) tip of an early bud is grafted into the body column, it induces a secondary axis, while the adjacent Cngsc(−) region has much weaker inductive capacities. Thus, Cngsc is expressed in a tissue that acts as an organizer. Cngsc is also expressed in the sensory neurons of the tip of the hypostome and in the epithelial endodermal cells of the upper part of the body column. The plausible roles of Cngsc in organizer function, head formation and anterior neuron differentiation are similar to roles goosecoid plays in vertebrates and Drosophila. It suggests widespread evolutionary conservation of the function of the gene.

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Norman, C. A., H. Hasan, and J. A. Sellwood. "Bar dissolution and bulge formation." Symposium - International Astronomical Union 171 (1996): 427. http://dx.doi.org/10.1017/s0074180900233457.

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We discuss the general classification of secular evolution in galaxies into terms of stellar dynamics. We present two-dimensional N-body simulations of a disk galaxy in which a central mass concentration is imposed after the formation of a strong bar. We show that the bar dissolves almost completely if the central mass concentration exceeds approximately 5% of the combined disk and bulge mass. This behavior can be understood in terms of previous work on single particle orbits (Hasan & Norman 1990, Hasan et al. 1993); the sustaining orbits aligned with the bar become stochastic as the Inner Lindblad resonance moves out past the minor axis of the bar. We present arguments that bar formation and subsequent thickening and dissolution will create a bulge-like stellar distribution from the central part of the disk. We discuss the predictions of such a model including the point that barred Scs with sufficient central mass concentrations should be building bulges now. We emphasize that bulges can come from a number of different mechanisms and we discuss the current evidence at both high and low redshift.

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Ferreira, Ana C. M., Valderez P. Ferreira, Dwight R. Soares, and Hugo S. Vilarroel-Leo. "Chemical and mineralogical characterization of elbaites from the Alto Quixaba pegmatite, Seridó province, NE Brazil." Anais da Academia Brasileira de Ciências 77, no. 4 (December 2005): 729–43. http://dx.doi.org/10.1590/s0001-37652005000400011.

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The Alto Quixaba pegmatite, Seridó region, northeastern Brazil, is a 60º/80ºSW-trending subvertical dike discordantly intruded into biotite schists of the Upper Neoproterozoic Seridó Formation. It has three distinct mineralogical and textural zones, besides a replacement body that cuts the pegmatite at its central portion and in which occur, among other gem minerals, colored elbaites. Elbaites usually occur as prismatic crystals, elongate according to the c-axis, with rounded faces and striations parallel to this axis. Optically, crystals are uniaxial negative with strong pleochroism; refractive index extraordinary axis = 1.619-1.622 and ordinary axis = 1.639-1.643, birefringence between 0.019 and 0.021, average relative density of 3.07, and the following unit cell parameters: ao = 15.845 Å, co = 7.085 Å and V = 1540.476 Å. There is alkali deficiency in the X site of 12-17%. The elbaites are relatively enriched in MnO (1.69 to 2.87%) and ZnO (up to 2.98%).

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Kawakami, Minoru, and Nobuki Nakanishi. "The role of an endogenous PKA inhibitor, PKIα, in organizing left-right axis formation." Development 128, no. 13 (July 1, 2001): 2509–15. http://dx.doi.org/10.1242/dev.128.13.2509.

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Protein kinase inhibitor (PKI) is an endogenous inhibitor of cAMP-dependent protein kinase A (PKA). We have found that the α-isoform of PKI (PKIα) is asymmetrically expressed along the left-right (L-R) axis in chick embryos. At stage 6, PKIα is expressed on the right side of the node, and this asymmetric expression continues until stage 7+. After stage 8, PKIα expression returns symmetric. Treatment of embryos with antisense PKIα oligonucleotides increased the incidence of reversed heart looping. Antisense oligonucleotides also induced ectopic expression of the left-specific genes Nodal and Pitx2, and suppressed the expression of the right-specific gene SnR in the right lateral plate mesoderm. Similarly, treatment with PKA activators forskolin and Sp-cAMPs resulted in both reversed heart looping and bilateral expression of Nodal. Ectopic activin induced PKIα on the left side of the node, while ectopic Shh and anti-Shh antibody had no effect on PKIα expression. Taken together, these data suggest that PKIα induced by an activin-like molecule, through the inhibition of PKA activity, suppresses the Nodal-Pitx2 pathway on the right side of the body.

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Chuong, C. M., G. Oliver, S. A. Ting, B. G. Jegalian, H. M. Chen, and E. M. De Robertis. "Gradients of homeoproteins in developing feather buds." Development 110, no. 4 (December 1, 1990): 1021–30. http://dx.doi.org/10.1242/dev.110.4.1021.

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Homeoproteins are functionally involved in pattern formation. Recently, homeoproteins have been shown to be distributed in a graded fashion in developing limb buds. Here we examine the expression of homeoproteins in chicken feather development by immunocytochemical localization. We find that XlHbox 1 antigen is present in cell nuclei and is distributed in a gradient in the mesoderm of developing feather buds, with strongest expression in the anterior-proximal region. The gradient is most obvious in feather buds from the mid-trunk level. Feather buds from the scapular level express very high levels of XlHbox 1 and feather buds from the caudal region express no XlHbox 1, suggesting that a broad gradient along the body axis is superimposed on a smaller gradient within each individual feather bud. Feather ectoderm also expresses XlHbox 1 antigen but without an obvious graded pattern. Another homeoprotein, Hox 5.2, is also expressed in developing feather buds in a graded way, and its distribution pattern is partially complementary to that of XlHbox 1. These observations suggest that homeoproteins may be involved in setting up the anteroposterior polarity of cell fields at different levels, first for the body axis, then for the limb axis and finally for the feather axis.

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Norman, Kenneth R., and Donald G. Moerman. "α spectrin is essential for morphogenesis and body wall muscle formation in Caenorhabditis elegans." Journal of Cell Biology 157, no. 4 (May 6, 2002): 665–77. http://dx.doi.org/10.1083/jcb.200111051.

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Acommon feature of multicellular animals is the ubiquitous presence of the spectrin cytoskeleton. Although discovered over 30 yr ago, the function of spectrin in nonerythrocytes has remained elusive. We have found that the spc-1 gene encodes the only α spectrin gene in the Caenorhabditis elegans genome. During embryogenesis, α spectrin localizes to the cell membrane in most if not all cells, starting at the first cell stage. Interestingly, this localization is dependent on β spectrin but not βHeavy spectrin. Furthermore, analysis of spc-1 mutants indicates that β spectrin requires α spectrin to be stably recruited to the cell membrane. Animals lacking functional α spectrin fail to complete embryonic elongation and die just after hatching. These mutant animals have defects in the organization of the hypodermal apical actin cytoskeleton that is required for elongation. In addition, we find that the process of elongation is required for the proper differentiation of the body wall muscle. Specifically, when compared with myofilaments in wild-type animals the myofilaments of the body wall muscle in mutant animals are abnormally oriented relative to the longitudinal axis of the embryo, and the body wall muscle cells do not undergo normal cell shape changes.

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Yao, Jie, and Daniel S. Kessler. "Goosecoid promotes head organizer activity by direct repression of Xwnt8 in Spemann’s organizer." Development 128, no. 15 (August 1, 2001): 2975–87. http://dx.doi.org/10.1242/dev.128.15.2975.

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Formation of the vertebrate body plan is controlled by discrete head and trunk organizers that establish the anteroposterior pattern of the body axis. The Goosecoid (Gsc) homeodomain protein is expressed in all vertebrate organizers and has been implicated in the activity of Spemann’s organizer in Xenopus. The role of Gsc in organizer function was examined by fusing defined transcriptional regulatory domains to the Gsc homeodomain. Like native Gsc, ventral injection of an Engrailed repressor fusion (Eng-Gsc) induced a partial axis, while a VP16 activator fusion (VP16-Gsc) did not, indicating that Gsc functions as a transcriptional repressor in axis induction. Dorsal injection of VP16-Gsc resulted in loss of head structures anterior to the hindbrain, while axial structures were unaffected, suggesting a requirement for Gsc function in head formation. The anterior truncation caused by VP16-Gsc was fully rescued by Frzb, a secreted Wnt inhibitor, indicating that activation of ectopic Wnt signaling was responsible, at least in part, for the anterior defects. Supporting this idea, Xwnt8 expression was activated by VP16-Gsc in animal explants and the dorsal marginal zone, and repressed by Gsc in Activin-treated animal explants and the ventral marginal zone. Furthermore, expression of Gsc throughout the marginal zone inhibited trunk formation, identical to the effects of Frzb and other Xwnt8 inhibitors. A region of the Xwnt8 promoter containing four consensus homeodomain-binding sites was identified and this region mediated repression by Gsc and activation by VP16-Gsc, consistent with direct transcriptional regulation of Xwnt8 by Gsc. Therefore, Gsc promotes head organizer activity by direct repression of Xwnt8 in Spemann’s organizer and this activity is essential for anterior development.

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Gray, G. L., I. Dobson, and D. C. Kammer. "Chaos in a Spacecraft Attitude Maneuver Due to Time-Periodic Perturbations." Journal of Applied Mechanics 63, no. 2 (June 1, 1996): 501–8. http://dx.doi.org/10.1115/1.2788896.

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We use Melnikov’s method to study the chaotic dynamics of an attitude transition maneuver of a torque-free rigid body in going from minor axis spin to major axis spin under the influence of small damping. The chaotic motion is due to the formation of Smale horseshoes which are caused by the oscillation of small subbodies inside the satellite. The equations of motion are derived and then transformed into a form suitable for the application of Melnikov’s method. An analytical criterion for chaotic motion is derived in terms of the system parameters. This criterion is evaluated for its significance to the design of artificial satellites.

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Nagao, Yusuke, Jinglei Cheng, Keiichiro Kamura, Ryoko Seki, Aya Maeda, Daichi Nihei, Sumito Koshida, et al. "Dynein axonemal intermediate chain 2 is required for formation of the left–right body axis and kidney in medaka." Developmental Biology 347, no. 1 (November 2010): 53–61. http://dx.doi.org/10.1016/j.ydbio.2010.08.001.

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Berenguer, Marie, Karolin F. Meyer, Jun Yin, and Gregg Duester. "Discovery of genes required for body axis and limb formation by global identification of retinoic acid–regulated epigenetic marks." PLOS Biology 18, no. 5 (May 18, 2020): e3000719. http://dx.doi.org/10.1371/journal.pbio.3000719.

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Gault, William J., Patricio Olguin, Ursula Weber, and Marek Mlodzik. "Drosophila CK1-γ, gilgamesh, controls PCP-mediated morphogenesis through regulation of vesicle trafficking." Journal of Cell Biology 196, no. 5 (March 5, 2012): 605–21. http://dx.doi.org/10.1083/jcb.201107137.

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Cellular morphogenesis, including polarized outgrowth, promotes tissue shape and function. Polarized vesicle trafficking has emerged as a fundamental mechanism by which protein and membrane can be targeted to discrete subcellular domains to promote localized protrusions. Frizzled (Fz)/planar cell polarity (PCP) signaling orchestrates cytoskeletal polarization and drives morphogenetic changes in such contexts as the vertebrate body axis and external Drosophila melanogaster tissues. Although regulation of Fz/PCP signaling via vesicle trafficking has been identified, the interplay between the vesicle trafficking machinery and downstream terminal PCP-directed processes is less established. In this paper, we show that Drosophila CK1-γ/gilgamesh (gish) regulates the PCP-associated process of trichome formation through effects on Rab11-mediated vesicle recycling. Although the core Fz/PCP proteins dictate prehair formation broadly, CK1-γ/gish restricts nucleation to a single site. Moreover, CK1-γ/gish works in parallel with the Fz/PCP effector multiple wing hairs, which restricts prehair formation along the perpendicular axis to Gish. Our findings suggest that polarized Rab11-mediated vesicle trafficking regulated by CK1-γ is required for PCP-directed processes.

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Berleth, T., and G. Jurgens. "The role of the monopteros gene in organising the basal body region of the Arabidopsis embryo." Development 118, no. 2 (June 1, 1993): 575–87. http://dx.doi.org/10.1242/dev.118.2.575.

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The monopteros (mp) gene contributes to apical-basal pattern formation in the Arabidopsis embryo. mp mutant seedlings lack basal body structures such as hypocotyl, radicle and root meristem, and this pattern deletion has been traced back to alterations in the octant-stage embryo. Cells of the embryo proper and the uppermost cell of the suspensor fail to establish division patterns that would normally generate the basal body structures. The resulting absence of a morphological axis seems to be responsible for another phenotypic trait of mp seedlings, variable positioning of cotyledons. This relationship is suggested by weak mp seedling phenotypes in which the presence of a short hypocotyl is correlated with normal arrangement of cotyledons. Root formation has been induced in mp seedlings grown in tissue culture. This result supports the notion that the mp gene is required for organising the basal body region, rather than for making the root, in the developing embryo.

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Journal articles on the topic 'Body axis formation'

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