Journal articles: 'Synaptonemal Complex'

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Lake, Cathleen M., and R. Scott Hawley. "Synaptonemal complex." Current Biology 31, no. 5 (March 2021): R225—R227. http://dx.doi.org/10.1016/j.cub.2021.01.015.

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2

Gillies, C. B. "Synaptonemal complex." Genome 31, no. 1 (January 1, 1989): 439–40. http://dx.doi.org/10.1139/g89-069.

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Heyting, C., A. J. J. Dietrich, P. B. Moens, R. J. Dettmers, H. H. Offenberg, E. J. W. Redeker, and A. C. G. Vink. "Synaptonemal complex proteins." Genome 31, no. 1 (January 1, 1989): 81–87. http://dx.doi.org/10.1139/g89-016.

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Synaptonemal complexes were isolated from rate spermatocytes for the purpose of biochemical and morphological analysis. Several monoclonal antibodies were elicited against purified synaptonemal complexes to study the composition and assembly of these structures. Four classes of antibodies could be discriminated according to the polypeptides that they recognize on Western blots of purified synaptonemal complexes, namely antibodies recognizing (i) a 190-kDa polypeptide; (ii) a 30- and a 33-kDa polypeptide; (iii) two polypeptides with molecular weights of about 120 kDa; and (iv) polypeptides with molecular weights of 66–55 kDa. The localization of these antigens within spermatocytes was analyzed light microscopically, by means of the immunoperoxidase technique and ultrastructurally, by immunogold labelling of surface-spread spermatocytes. The 66-to 55-kDa polypeptides are not confined to synaptonemal complexes; rather, these polypeptides appear to be chromosomal components. The 190-, 30-, and 33-kDa polypeptides make part of the lateral elements of paired as well as unpaired segments of synaptonemal complexes. The 120-kDa polypeptides were localized on the inner edge of the lateral elements, specifically in paired segments of synaptonemal complexes. The distribution of the 190-, 120-, 30-, and 33-kDa polypeptides within the testis was analyzed by immunofluorescence staining of cryostat sections. All these polypeptides turned out to be specific for nuclei of zygotene up to and including diplotene spermatocytes. Only in some early spermatids could the 190-, 30-, and 33-kDa polypeptides be detected, presumably in remnants of synaptonemal complexes. We conclude that the lateral elements of synaptonemal complexes do not arise by rearrangement of pre-existing components in the nucleus, but that their major components are newly synthesized during meiotic prophase.Key words: synaptonemal complex, immunocytochemistry, meiosis.

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Fedotova, Yu S., O. L. Kolomiets, and Yu F. Bogdanov. "Synaptonemal complex transformations in rye microsporocytes at the diplotene stage of meiosis." Genome 32, no. 5 (October 1, 1989): 816–23. http://dx.doi.org/10.1139/g89-516.

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The process of synaptonemal complex degradation during diplotene was studied in spreads of rye microsporocytes stained with silver nitrate at pH 3.5–4.5 and 6.0–8.0. Two different patterns of the synaptonemal complex degradation process have been observed, depending on the two staining procedures used. Progressive synaptonemal complex fragmentation observable at the higher pH appeared to be absent in staining at pH 3.5–4.5: thin connecting threads have been found in the "gaps" between the synaptonemal complex segments. Complete tracing of the synaptonemal complex degradation process was attempted and revealed the following successive steps: (i) local repulsion of lateral elements; (ii) lateral element looping in the regions of repulsion; (iii) extension of the loops; (iv) transformation of the extended loops into coils of irregular shape with a diameter of about 2 μm and a pitch of about 1.2 μm; and (v) formation of paired beanlike thickenings on a gyral coil. In asynaptic mutant sy-9 unpaired lateral elements are transformed without looping into a similar coil but with single beanlike thickenings. We conclude that synaptonemal complex lateral element loops at diplotene are invisible after the routine silver staining of microspreads (at pH about 6 and higher) and look like gaps between discontinuous synaptonemal complex segments, thus simulating the process of synaptonemal complex fragmentation.Key words: synaptonemal complex, diplotene, rye.

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5

Grishayeva, T. M., and Y. F. Bogdanov. "Dependence on genie balance for synaptonemal complex formation in Drosophila melanogaster." Genome 30, no. 2 (April 1, 1988): 258–64. http://dx.doi.org/10.1139/g88-044.

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Electron microscopic examination of gonads of Drosophila melanogaster with different genotypes, including a metafemale 3X;2A and an intersex XXY;3A, have revealed that the formation of synaptonemal complexes is controlled by the genie balance, i.e., the ratio of X chromosomes to autosomes. The Y chromosome is not involved in the genetic control of the formation of precursors of the central element of synaptonemal complexes in males, nor does it disturb their formation in [Formula: see text] females. Hyperploidy for sections 1 – 3A and 18A – 20 of the X chromosome does not lead to the appearance of synaptonemal complexes in males and does not interfere with their formation in females. Females hyperploid for extensive regions of the X chromosome (sections 1 – 11A, 11A – 20, and 8C – 20) are fertile and show apparently normal formation of synaptonemal complexes. Hyperploidy for sections 8C – 11A of the X results in a sharp decrease in the viability of females, in abnormal differentiation of ovary cells, and in the lack of synaptonemal complexes. These data suggest a possible important role for the sections 8C – 11A in the genic balance controlling the formation of synaptonemal complexes in D. melanogaster. The lack of synaptonemal complexes in hypoploid females may be the result of abnormal cell differentiation in gonads.Key words: Drosophila melanogaster, synaptonemal complex, sex chromosomes, genic balance.

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Wallace, B. M. N., and H. Wallace. "Synaptonemal complex karyotype of zebrafish." Heredity 90, no. 2 (February 2003): 136–40. http://dx.doi.org/10.1038/sj.hdy.6800184.

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7

Loidl, J., and G. H. Jones. "Synaptonemal complex spreading in Allium." Chromosoma 93, no. 5 (April 1986): 420–28. http://dx.doi.org/10.1007/bf00285824.

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8

Benavente, Ricardo. "The synaptonemal complex—50 years." Chromosoma 115, no. 3 (February 11, 2006): 151. http://dx.doi.org/10.1007/s00412-006-0050-z.

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9

Greenbaum, Ira F., David W. Hale, Philip D. Sudman, and Eviatar Nevo. "Synaptonemal complex analysis of mole rats (Spalax ehrenbergi): unusual polymorphisms of chromosome." Genome 33, no. 6 (December 1, 1990): 898–902. http://dx.doi.org/10.1139/g90-135.

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Two unusual structural polymorphisms in the largest chromosomal pair of the Israeli mole rat, Spalax ehrenbergi, were analyzed from surface-spread and silver-stained preparations of synaptonemal complexes. A C-band negative polymorphism for the length of the 1p arm was visible as axial length differences during late zygonema and early pachynema. This region underwent synaptic adjustment resulting in a fully paired, mid-pachytene synaptonemal complex with equalized axial lengths. The somatically variable and nonargentophilic secondary constriction in the 1q arm was evident as a distinct silver-stained thickening along the synaptonemal complex. Presence of this structure on the synaptonemal complex varied both among individuals and among cells within individuals. The intraindividual variation of this region is hypothesized to represent differential biochemical activity with its cellular visualization being regulated in a manner similar to that of nucleolus organizer regions.Key words: mole rats, synaptonemal complex, chromosomal polymorphism.

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10

Sherman, Jamie D., Stephen M. Stack, and Lorinda K. Anderson. "Two-dimensional spreads of synaptonemal complexes from solanaceous plants. IV. Synaptic irregularities." Genome 32, no. 5 (October 1, 1989): 743–53. http://dx.doi.org/10.1139/g89-507.

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Irregularities in the structure of synaptonemal complexes have been reported in a wide variety of organisms, but so far there has been no study concentrating on synaptic irregularities per se. We have used a hypotonic bursting technique to spread synaptonemal complexes from autotetraploid Solanum tuberosum (potato) and diploid, tetraploid, and trisomic Lycopersicon esculentum (tomato). In this study we observed most of the synaptic irregularities that have been reported in other organisms as well as an irregularity that has not been illustrated previously (lateral element buckles containing additional synaptonemal complex components). These observations have been used to provide partial answers to the following questions about the formation of the synaptonemal complex. (i) In what way does homology affect synapsis? (ii) What controls multiple synapsis? (iii) What is the relationship of synaptonemal complex components to chromatin and to each other? (iv) Do lateral elements have structural or functional polarity?Key words: synaptonemal complexes, synapsis, synaptic irregularities, solanaceous plants.

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11

Gillies, C. B., and A. J. Lukaszewski. "Synaptonemal complex formation in rye (Secale cereale) heterozygous for telomeric C-bands." Genome 32, no. 5 (October 1, 1989): 901–7. http://dx.doi.org/10.1139/g89-527.

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Zygotene–pachytene nuclei from a rye line heterozygous for most terminal C-bands were found by electron microscopic spreading analysis to have unequal lateral elements at most synaptonemal complex telomeres. An unpaired lateral element protruded beyond the end of the synaptonemal complex at each such telomere. Another rye line with only one C-band heterozygous telomere had only one uneven synaptonemal complex telomere. The length differences between paired lateral elements in heterozygotes (both total complement and individual synaptonemal complexes) was considerably less than the difference in DNA content or somatic metaphase chromosome size between C-band positive and C-band negative lines. There was no evidence of a synaptic adjustment effect reducing the telomere length differences in later pachytene–diplotene stage nuclei. Heterozygosity for the 1RL terminal C-band resulted in a slight reduction in chiasma frequency in that arm but no shift in chiasma position.Key words: rye, C-bands, telomeres, chromosome pairing, synaptonemal complex.

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12

Feng, Jianrong, Shijuan Fu, Xuan Cao, Hao Wu, Jing Lu, Ming Zeng, Lin Liu, Xue Yang, and Yuequan Shen. "Synaptonemal complex protein 2 (SYCP2) mediates the association of the centromere with the synaptonemal complex." Protein & Cell 8, no. 7 (February 1, 2017): 538–43. http://dx.doi.org/10.1007/s13238-016-0354-6.

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13

Giroux, Craig N., Michael E. Dresser, and Howard F. Tiano. "Genetic control of chromosome synapsis in yeast meiosis." Genome 31, no. 1 (January 1, 1989): 88–94. http://dx.doi.org/10.1139/g89-017.

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Both meiosis-specific and general recombination functions, recruited from the mitotic cell cycle, are required for elevated levels of recombination and for chromosome synapsis (assembly of the synaptonemal complex) during yeast meiosis. The meiosis-specific SPO11 gene (previously shown to be required for meiotic recombination) has been isolated and shown to be essential for synaptonemal complex formation but not for DNA metabolism during the vegetative cell cycle. In contrast, the RAD52 gene is required for mitotic and meiotic recombination but not for synaptonemal complex assembly. These data suggest that the synaptonemal complex may be necessary but is clearly not sufficient for meiotic recombination. Cytological analysis of spread meiotic nuclei demonstrates that chromosome behavior in yeast is comparable with that observed in larger eukaryotes. These spread preparations support the immunocytological localization of specific proteins in meiotic nuclei. This combination of genetic, molecular cloning, and cytological approaches in a single experimental system provides a means of addressing the role of specific gene products and nuclear structures in meiotic chromosome behavior.Key words: synaptonemal complex, chromosome behavior, meiosis.

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14

Maguire, Marjorie P., and Robert W. Riess. "Synaptonemal complex behavior in asynaptic maize." Genome 34, no. 1 (February 1, 1991): 163–68. http://dx.doi.org/10.1139/g91-025.

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Synatonemal complexes were studied in silver-stained spread preparations of microsporocyte complements of asynaptic maize. Complexes were found predominantly in terminal regions of chromosome pairs. These tend to be aggregated in a common portion of the nucleus and to have polar orientation. As many as 19 of the 20 ends were found to be involved in relatively short paired segments. Intercalary regions of cores were not strongly organized and aligned, but some contained completed synaptonemal complex segments. The defect in asynaptic appears to represent stalling of the synaptic process at an early stage of synaptic progression.Key words: chromosome pairing, synaptonemal complex, synaptic defect.

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15

Grishaeva, T. M., and Yu F. Bogdanov. "Synaptonemal Complex Proteins: Unicity or Universality?" Russian Journal of Genetics 57, no. 8 (August 2021): 912–19. http://dx.doi.org/10.1134/s1022795421080068.

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16

Moens, P. B., C. Heyting, A. J. Dietrich, W. van Raamsdonk, and Q. Chen. "Synaptonemal complex antigen location and conservation." Journal of Cell Biology 105, no. 1 (July 1, 1987): 93–103. http://dx.doi.org/10.1083/jcb.105.1.93.

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The axial cores of chromosomes in the meiotic prophase nuclei of most sexually reproducing organisms play a pivotal role in the arrangement of chromatin, in the synapsis of homologous chromosomes, in the process of genetic recombination, and in the disjunction of chromosomes. We report an immunogold analysis of the axial cores and the synaptonemal complexes (SC) using two mouse monoclonal antibodies raised against isolated rat SCs. In Western blots of purified SCs, antibody II52F10 recognizes a 30- and a 33-kD peptide (Heyting, C., P. B. Moens, W. van Raamsdonk, A. J. J. Dietrich, A. C. G. Vink, and E. J. W. Redeker, 1987, Eur. J. Cell Biol., 43: 148-154). In spreads of rat spermatocyte nuclei it produces gold grains over the cores of autosomal and sex chromosomes. The cores label lightly during the chromosome pairing stage (zygotene) of early meiotic prophase and they become more intensely labeled when they are parallel aligned as the lateral elements of the SC during pachytene (55 grains/micron SC). Statistical analysis of electronically recorded gold grain positions shows that the two means of the bimodal gold grain distribution coincide with the centers of the lateral elements. At diplotene, when the cores separate, the antigen is still detected along the length of the core and the enlarged ends are heavily labeled. Shadow-cast SC preparations show that recombination nodules are not labeled. The continued presence suggests that the antigens serve a continuing function in the cores, such as chromatin binding, and/or structural integrity. Antibody III15B8, which does not recognize the 30- and 33-kD peptides, produces gold grains predominantly between the lateral elements. The grain distribution is bimodal with the mean of each peak just inside the pairing face of the lateral element. The antigen is present where and while the cores of the homologous chromosomes are paired. From the location and the timing, it is assumed that the antigen recognized by III15B8 functions in chromosome pairing at meiotic prophase. The two anti-rat SC antibodies label rat and mouse SCs but not rabbit or dog SCs. A positive control using human CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) anti-centromere serum gives equivalent labeling of SC centromeres in the rat, mouse, rabbit, and dog. It is concluded that the SC antigens recognized by II52F10 and III15B8 are not widely conserved. The two antibodies do not bind to cellular or nuclear components of somatic cells.(ABSTRACT TRUNCATED AT 400 WORDS)

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17

Ünal, F., and R. S. Callow. "Synaptonemal complex formation inLathyrus sativusandL. tingitanus." Caryologia 48, no. 3-4 (January 1995): 225–38. http://dx.doi.org/10.1080/00087114.1995.10797332.

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18

Vidal, F., J. Navarro, C. Templado, and J. Egozcue. "Synaptonemal complex studies in the male." Human Reproduction 2, no. 7 (October 1987): 577–81. http://dx.doi.org/10.1093/oxfordjournals.humrep.a136592.

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19

Jones, M., H. Rees, and G. Jenkins. "Synaptonemal complex formation in Avena polyploids." Heredity 63, no. 2 (October 1989): 209–19. http://dx.doi.org/10.1038/hdy.1989.94.

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20

del Cacho, Emilio, Marc Pages, Margarita Gallego, Luis Monteagudo, and Caridad Sánchez-Acedo. "Synaptonemal complex karyotype of Eimeria tenella." International Journal for Parasitology 35, no. 13 (November 2005): 1445–51. http://dx.doi.org/10.1016/j.ijpara.2005.06.009.

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21

Schwarzacher-Robinson, Trude, and Dieter Schweizer. "Synaptonemal complex spreading in plants: Technical aspects and preliminary observations on the synaptonemal complex inPaeonia andOrnithogalum." Plant Systematics and Evolution 154, no. 1-2 (1986): 129–36. http://dx.doi.org/10.1007/bf00984873.

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22

Stack, Stephen M., Lorinda K. Anderson, and Jamie D. Sherman. "Chiasmata and recombination nodules in Lilium longiflorum." Genome 32, no. 3 (June 1, 1989): 486–98. http://dx.doi.org/10.1139/g89-473.

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We determined the frequency of chiasmata at late diplotene in microsporocytes of Lilium longiflorum (lily). Because there are long, intimate associations of homologous chromosomes in addition to short associations that appear to be single chiasmata, the number of chiasmata counted depends on how the long associations are interpreted. Using a defined method, we determined that there was an average of 54.8 ± 6.0 chiasmata per complete set of diplotene bivalents. Recombination nodules are 100-nm ellipsoids that are found on the central element of synaptonemal complexes. There is correlative evidence that strongly indicates recombination nodules are located at the sites of crossing-over in late pachytene. Using spreads of synaptonemal complexes stained with uranyl acetate – lead citrate, we determined that the frequency of recombination nodules was 1/57.2 μm of synaptonemal complex. Using separate silver-stained spreads of synaptonemal complexes from lily microsporocytes, we determined that the average length of a complete set of pachytene synaptonemal complexes was 3149 ± 668 μm. Therefore, an average set of synaptonemal complexes would have 55.1 (3149 ÷ 57.2) recombination nodules, a number that closely matches the average number of chiasmata in a set of late diplotene bivalents.Key words: chiasmata, recombination nodules, synaptonemal complex, Lilium longiflorum.

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23

Yuan, Li, Jeanette Pelttari, Eva Brundell, Birgitta Björkroth, Jian Zhao, Jian-Guo Liu, Hjalmar Brismar, Bertil Daneholt, and Christer Höög. "The Synaptonemal Complex Protein SCP3 Can Form Multistranded, Cross-striated Fibers In Vivo." Journal of Cell Biology 142, no. 2 (July 27, 1998): 331–39. http://dx.doi.org/10.1083/jcb.142.2.331.

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The synaptonemal complex protein SCP3 is part of the lateral element of the synaptonemal complex, a meiosis-specific protein structure essential for synapsis of homologous chromosomes. We have investigated the fiber-forming properties of SCP3 to elucidate its role in the synaptonemal complex. By synthesis of SCP3 in cultured somatic cells, it has been shown that SCP3 can self-assemble into thick fibers and that this process requires the COOH-terminal coiled coil domain of SCP3, as well as the NH2-terminal nonhelical domain. We have further analyzed the thick SCP3 fibers by transmission electron microscopy and immunoelectron microscopy. We found that the fibers display a transversal striation with a periodicity of ∼20 nm and consist of a large number of closely associated, thin fibers, 5–10 nm in diameter. These features suggest that the SCP3 fibers are structurally related to intermediate filaments. It is known that in some species the lateral elements of the synaptonemal complex show a highly ordered striated structure resembling that of the SCP3 fibers. We propose that SCP3 fibers constitute the core of the lateral elements of the synaptonemal complex and function as a molecular framework to which other proteins attach, regulating DNA binding to the chromatid axis, sister chromatid cohesion, synapsis, and recombination.

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Spyropoulos, B., D. Wise, and P. B. Moens. "Localized recombination nodules and sex chromosome behavior in the male mole cricket, Neocurtilla hexadactyla." Genome 32, no. 2 (April 1, 1989): 275–81. http://dx.doi.org/10.1139/g89-440.

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During meiotic prophase, the 10 metacentric autosomal bivalents of the mole cricket, Neocurtilla hexadactyla Perty, formed synaptonemal complexes only at their ends. These complexes were of similar morphology to those of other species. Virtually all of these distal synaptonemal complex segments contained one or more recombination nodules. There was complete correlation between the locations of the synaptonemal complex segments at pachytene and chiasmata at diplotene. The sex chromosomal bivalent X2 and Y, formed a synaptonemal complex at one end only. While no apparent physical or spatial connection was found during prophase between the X2Y bivalent and the third sex chromosome, X1, electron-dense material covered the centromeres of X1 and Y and to a lesser extent X2, thus differentiating the centromeres of the sex chromosomes from those of the autosomes.Key words: localised pairing, recombination nodules, chiasmata, sex chromosomes.

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25

Naranjo, T., A. Roca, P. G. Goicoechea, J. H. de Jong, and W. D. Smilde. "Comparison between synaptonemal complexes at pachytene and chromosome association at metaphase I in heterozygotes for a "nonreciprocal" translocation of rye." Genome 32, no. 6 (December 1, 1989): 983–91. http://dx.doi.org/10.1139/g89-542.

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A comparative analysis of synaptonemal complex formation at pachytene and chromosome association at metaphase I was carried out in heterozygotes for translocation T242W (2R/6R) of rye (Secale cereale L.). Synaptonemal complex formation supported earlier light microscopic observations that one exchanged segment of this translocation was very small and restricted to the telomere or had been lost. Negative interference between the interstitial segments with respect to chiasma formation was detected at metaphase I. This interference was apparently the result of the simultaneous occurrence of either asynapsis or nonhomologous pairing around the translocation point at pachytene. Negative interference detected across the centromere of 6R was attributed to nonhomologous pairing. The presence of an intercalary C-band in the interstitial segment 2RLi or in the 1RS arm had no apparent influence on synaptonemal complex formation. Unmatched ends of synaptonemal complex 1R and of the multivalent were in most cases associated with heterozygosity for the telomeric C-heterochromatin.Key words: Secale cereale, translocation, synapsis, interference, C-banding.

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Bojko, Maja. "Presence of abnormal synaptonemal complexes in heterothallic species of Neurospora." Genome 30, no. 5 (October 1, 1988): 697–709. http://dx.doi.org/10.1139/g88-117.

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Synaptonemal complex abnormalities are frequent in reconstructed meiotic prophase nuclei of Neurospora crassa and Neurospora intermedia. Three kinds of synaptonemal complex anomalies were seen: lateral component splits, lateral component junctions, and multiple complexes. The anomalies apparently are formed during or after the pairing process, as they were not seen in the largely unpaired early zygotene chromosomes. Their presence at all the other substages from mid-zygotene to late pachytene indicates that they are not eliminated before the synaptonemal complex decomposes at diplotene. Abnormal synaptonemal complexes were seen in all 19 crosses of N. crassa and N. intermedia that were examined, including matings between standard laboratory strains, inversions, Spore killers, and strains collected from nature. The frequency of affected nuclei and degree of abnormality within a nucleus varied in different matings. No abnormalities were present in the homothallic species Neurospora africana and Neurospora terricola. Structural chromosome aberrations, introgression, and heterozygosity have been eliminated as causes for pairing disorder. The abnormal synaptonemal complexes seemingly do not interfere with normal ascus development and ascospore formation. The affected nuclei are not aborted during meiotic prophase, nor are they eliminated by abortion of mature asci. The abnormal meiocytes do not lead to aneuploidy, as judged by the low frequency of white ascospores in crosses between wild type strains that have many abnormalities. Thus, the abnormal synatonemal complexes do not appear to prevent chiasma formation between homologues.Key words: Neurospora, meiosis, synaptonemal complex.

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Dobson, M. J., R. E. Pearlman, A. Karaiskakis, B. Spyropoulos, and P. B. Moens. "Synaptonemal complex proteins: occurrence, epitope mapping and chromosome disjunction." Journal of Cell Science 107, no. 10 (October 1, 1994): 2749–60. http://dx.doi.org/10.1242/jcs.107.10.2749.

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We have used polyclonal antibodies against fusion proteins produced from cDNA fragments of a meiotic chromosome core protein, Cor1, and a protein present only in the synapsed portions of the cores, Syn1, to detect the occurrence and the locations of these proteins in rodent meiotic prophase chromosomes. The 234 amino acid Cor1 protein is present in early unpaired cores, in the lateral domains of the synaptonemal complex and in the chromosome cores when they separate at diplotene. A novel observation showed the presence of Cor1 axial to the metaphase I chromosomes and substantial amounts of Cor1 in association with pairs of sister centromeres. The centromere-associated Cor1 protein becomes dissociated from the centromeres at anaphase II and it is not found in mitotic metaphase centromeres. The extended presence of Cor1 suggests that it may have a role in chromosome disjunction by fastening chiasmata at metaphase I and by joining sister kinetochores, which ensures co-segregation at anaphase I. Two-colour immunofluorescence of Cor1 and Syn1 demonstrates that synapsis between homologous cores is initiated at few sites but advances rapidly relative to the establishment of new initiation sites. If the rapid advance of synapsis deters additional initiation sites between pairs of homologues, it may provide a mechanism for positive recombination interference. Immunogold epitope mapping of antibodies to four Syn1 fusion proteins places the amino terminus of Syn1 towards the centre of the synaptonemal complex while the carboxyl terminus extends well into the lateral domain of the synaptonemal complex. The Syn1 fusion proteins have a non-specific DNA binding capacity. Immunogold labelling of Cor1 antigens indicates that the lateral domain of the synaptonemal complex is about twice as wide as the apparent width of lateral elements when stained with electron-dense metal ions. Electron microscopy of shadow-cast surface-spread SCs confirms the greater width of the lateral domain. The implication of these dimensions is that the proteins that comprise the synaptic domain overlap with the protein constituents of the lateral domains of the synaptonemal complex more than was apparent from earlier observations. This arrangement suggests that direct interactions might be expected between some of the synaptonemal complex proteins.

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Wallace, H., and B. M. N. Wallace. "Complete meiotic pairing of crested newt chromosomes." Genome 38, no. 6 (December 1, 1995): 1105–11. http://dx.doi.org/10.1139/g95-147.

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The longest chromosome (number 1) of Trituturus cristatus carries a heteromorphic segment, a heterozygosity perpetuated by a balanced lethal system. The heteromorphic segment is regarded as achiasmate and has been claimed to be asynaptic. Direct observations of chromosome pairing in spermatocytes and oocytes yield some cases where all homologous chromosomes appear to be completely paired, but the individual bivalents could not be identified as pachytene is not particularly clear in this species. The long arms of bivalent 1 usually remain attached by a terminal chiasma in spermatocytes of T. c. cristatus but the corresponding chiasma is only rarely present in T. c. carnifex spermatocytes. Synaptonemal complexes have been measured in both spermatocytes and oocytes of T. c. cristatus. A karyotype constructed from these measurements matches the main features of somatic and lampbrush chromosome karyotypes, indicating that all chromosomes must be completely paired and proportionately represented as synaptonemal complex. The total length of synaptonemal complex is much the same in spermatocytes and oocytes and is similar to the length in spermatocytes of Xenopus laevis. These two amphibian examples supplement a recent survey of other vertebrate classes to reinforce its conclusion that synaptonemal complex length is not related to genome size in vertebrates.Key words: chromosome pairing, synaptonemal complex, genome size, amphibia.

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Thomas, Hum M., and W. G. Morgan. "Analysis of synaptonemal complexes and chromosome pairing at metaphase I in the diploid intergeneric hybrid Lolium multiflorum × Festuca drymeja." Genome 33, no. 4 (August 1, 1990): 465–71. http://dx.doi.org/10.1139/g90-069.

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The synaptonemal complexes in the diploid hybrid Lolium multiflorum × Festuca drymeja were examined by the surface spreading technique, and chromosome pairing at metaphase I was analysed. Synaptonemal complex analysis revealed "illegitimate" pairing, including multivalents and foldback pairing. At metaphase I, most chiasmata were between chromosomes of the same genome, and again multivalents were found. It was concluded that most synaptonemal complexes resulted in chiasma formation. The effects of the large differences in DNA values of the two species and the possible genotypic effect of F. drymeja on chromosome pairing are discussed.Key words: Lolium-Festuca, synaptonemal complexes, nonhomologous pairing, DNA values.

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Chen, Qianfa, Ronald E. Pearlman, and Peter B. Moens. "Isolation and characterization of a cDNA encoding a synaptonemal complex protein." Biochemistry and Cell Biology 70, no. 10-11 (October 1, 1992): 1030–38. http://dx.doi.org/10.1139/o92-147.

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A gene encoding a 65-kilodalton antigen of the rat synaptonemal complex, SC65, has been cloned by screening rat testis λgt11 and λZAPII cDNA expression libraries using polyclonal antibodies against rat synaptonemal complex proteins. The longest open reading frame, initiating at an ATG codon in the cDNA, encodes a protein of 431 amino acids, with a relative molecular mass of 50 000. Immunological analysis locates the SC65 gene product on the synaptonemal complex between the pairing faces of the parallel aligned cores of homologous chromosomes in spermatocytes. Of the rat tissues examined, the SC65 gene is transcribed in testis, brain, and heart at similar levels, and in the liver at a much lower level. The DNA sequence extending about 80 base pairs downstream of the translation termination codon has 93% similarity to the identifier sequence present in the rat genome in 1 × 105 – 1.5 × 105 copies and in cDNA clones of precursors of brain-specific mRNAs. The amino acid sequence encoded by the SC65 gene contains an acidic region in the C-terminal domain of the protein, potential glycosylation sites, and at least one possible phosphorylation site. The protein shows no overall similarity to proteins of known function, nor is there similarity to protein sequences present in GenBank or EMBL data bases.Key words: meiosis, synaptonemal complex, antibody, rat testis cDNA library, molecular cloning.

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Chuong, Hoa, and Dean S. Dawson. "Meiotic Cohesin Promotes Pairing of Nonhomologous Centromeres in Early Meiotic Prophase." Molecular Biology of the Cell 21, no. 11 (June 2010): 1799–809. http://dx.doi.org/10.1091/mbc.e09-05-0392.

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A period of pairing between nonhomologous centromeres occurs early in meiosis in a diverse collection of organisms. This early, homology-independent, centromere pairing, referred to as centromere coupling in budding yeast, gives way to an alignment of homologous centromeres as homologues synapse later in meiotic prophase. The regulation of centromere coupling and its underlying mechanism have not been elucidated. In budding yeast, the protein Zip1p is a major component of the central element of the synaptonemal complex in pachytene of meiosis, and earlier, is essential for centromere coupling. The experiments reported here demonstrate that centromere coupling is mechanistically distinct from synaptonemal complex assembly. Zip2p, Zip3p, and Red1p are all required for the assembly of Zip1 into the synaptonemal complex but are dispensable for centromere coupling. However, the meiotic cohesin Rec8p is required for centromere coupling. Loading of meiotic cohesins to centromeres and cohesin-associated regions is required for the association of Zip1 with these sites, and the association of Zip1 with the centromeres then promotes coupling. These findings reveal a mechanism that promotes associations between centromeres before the assembly of the synaptonemal complex, and they demonstrate that chromosomes are preloaded with Zip1p in a manner that may promote synapsis.

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del Priore, Lucía, and María Inés Pigozzi. "DNA Organization along Pachytene Chromosome Axes and Its Relationship with Crossover Frequencies." International Journal of Molecular Sciences 22, no. 5 (February 27, 2021): 2414. http://dx.doi.org/10.3390/ijms22052414.

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During meiosis, the number of crossovers vary in correlation to the length of prophase chromosome axes at the synaptonemal complex stage. It has been proposed that the regular spacing of the DNA loops, along with the close relationship of the recombination complexes and the meiotic axes are at the basis of this covariation. Here, we use a cytogenomic approach to investigate the relationship between the synaptonemal complex length and the DNA content in chicken oocytes during the pachytene stage of the first meiotic prophase. The synaptonemal complex to DNA ratios of specific chromosomes and chromosome segments were compared against the recombination rates obtained by MLH1 focus mapping. The present results show variations in the DNA packing ratios of macro- and microbivalents and also between regions within the same bivalent. Chromosome or chromosome regions with higher crossover rates form comparatively longer synaptonemal complexes than expected based on their DNA content. These observations are compatible with the formation of higher number of shorter DNA loops along meiotic axes in regions with higher recombination levels.

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Grey, Corinne, and Bernard de Massy. "Coupling crossover and synaptonemal complex in meiosis." Genes & Development 36, no. 1-2 (January 1, 2022): 4–6. http://dx.doi.org/10.1101/gad.349286.121.

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During meiosis, a molecular program induces DNA double-strand breaks (DSBs) and their repair by homologous recombination. DSBs can be repaired with or without crossovers. ZMM proteins promote the repair toward crossover. The sites of DSB repair are also sites where the axes of homologous chromosomes are juxtaposed and stabilized, and where a structure called the synaptonemal complex initiates, providing further regulation of both DSB formation and repair. How crossover formation and synapsis initiation are linked has remained unknown. The study by Pyatnitskaya and colleagues (pp. 53–69) in this issue of Genes & Development highlights the central role of the Saccharomyces cerevisiae ZMM protein Zip4 in this process.

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Fraune, Johanna, Céline Brochier-Armanet, Manfred Alsheimer, Jean-Nicolas Volff, Katharina Schücker, and Ricardo Benavente. "Evolutionary history of the mammalian synaptonemal complex." Chromosoma 125, no. 3 (March 12, 2016): 355–60. http://dx.doi.org/10.1007/s00412-016-0583-8.

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Lu, Benjamin C. "Spreading the synaptonemal complex of Neurospora crassa." Chromosoma 102, no. 7 (July 1993): 464–72. http://dx.doi.org/10.1007/bf00357101.

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36

Maguire, M. P. "Is the Synaptonemal Complex a Disjunction Machine?" Journal of Heredity 86, no. 5 (September 1995): 330–40. http://dx.doi.org/10.1093/oxfordjournals.jhered.a111600.

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Tarsounas, M., R. E. Pearlman, P. J. Gasser, M. S. Park, and P. B. Moens. "Protein-protein interactions in the synaptonemal complex." Molecular Biology of the Cell 8, no. 8 (August 1997): 1405–14. http://dx.doi.org/10.1091/mbc.8.8.1405.

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In mammalian systems, an approximately M(r) 30,000 Cor1 protein has been identified as a major component of the meiotic prophase chromosome cores, and a M(r) 125,000 Syn1 protein is present between homologue cores where they are synapsed and form the synaptonemal complex (SC). Immunolocalization of these proteins during meiosis suggests possible homo- and heterotypic interactions between the two as well as possible interactions with yet unrecognized proteins. We used the two-hybrid system in the yeast Saccharomyces cerevisiae to detect possible protein-protein associations. Segments of hamsters Cor1 and Syn1 proteins were tested in various combinations for homo- and heterotypic interactions. In the cause of Cor1, homotypic interactions involve regions capable of coiled-coil formation, observation confirmed by in vitro affinity coprecipitation experiments. The two-hybrid assay detects no interaction of Cor1 protein with central and C-terminal fragments of Syn1 protein and no homotypic interactions involving these fragments of Syn1. Hamster Cor1 and Syn1 proteins both associate with the human ubiquitin-conjugation enzyme Hsubc9 as well as with the hamster Ubc9 homologue. The interactions between SC proteins and the Ubc9 protein may be significant for SC disassembly, which coincides with the repulsion of homologs by late prophase I, and also for the termination of sister centromere cohesiveness at anaphase II.

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Kouznetsova, Anna, Ricardo Benavente, Albert Pastink, and Christer Höög. "Meiosis in Mice without a Synaptonemal Complex." PLoS ONE 6, no. 12 (December 2, 2011): e28255. http://dx.doi.org/10.1371/journal.pone.0028255.

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Sun, F., C. Greene, P. J. Turek, E. Ko, A. Rademaker, and R. H. Martin. "Immunofluorescent synaptonemal complex analysis in azoospermic men." Cytogenetic and Genome Research 111, no. 3-4 (2005): 366–70. http://dx.doi.org/10.1159/000086913.

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Henderson, Kiersten A., and Scott Keeney. "Synaptonemal complex formation: where does it start?" BioEssays 27, no. 10 (2005): 995–98. http://dx.doi.org/10.1002/bies.20310.

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Hasenkampf, Clare A., and Margaret Y. Menzel. "SYNAPTONEMAL COMPLEX KARYOTYPING OF TRADESCANTIA ZYGOTENE NUCLEI." American Journal of Botany 72, no. 5 (May 1985): 666–73. http://dx.doi.org/10.1002/j.1537-2197.1985.tb08324.x.

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Llano, Elena, and Alberto M. Pendás. "Synaptonemal Complex in Human Biology and Disease." Cells 12, no. 13 (June 25, 2023): 1718. http://dx.doi.org/10.3390/cells12131718.

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The synaptonemal complex (SC) is a meiosis-specific multiprotein complex that forms between homologous chromosomes during prophase of meiosis I. Upon assembly, the SC mediates the synapses of the homologous chromosomes, leading to the formation of bivalents, and physically supports the formation of programmed double-strand breaks (DSBs) and their subsequent repair and maturation into crossovers (COs), which are essential for genome haploidization. Defects in the assembly of the SC or in the function of the associated meiotic recombination machinery can lead to meiotic arrest and human infertility. The majority of proteins and complexes involved in these processes are exclusively expressed during meiosis or harbor meiosis-specific subunits, although some have dual functions in somatic DNA repair and meiosis. Consistent with their functions, aberrant expression and malfunctioning of these genes have been associated with cancer development. In this review, we focus on the significance of the SC and their meiotic-associated proteins in human fertility, as well as how human genetic variants encoding for these proteins affect the meiotic process and contribute to infertility and cancer development.

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Jenkins, G., and A. Okumus. "Indiscriminate synapsis in achiasmate Allium fistulosum L. (Liliaceae)." Journal of Cell Science 103, no. 2 (October 1, 1992): 415–22. http://dx.doi.org/10.1242/jcs.103.2.415.

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Seedlings of Allium fistulosum (2n=2x=16) were treated with aqueous colchicine with the intention of inducing tetraploidy. One treated, but undoubled, diploid mutant is described which consistently fails to form any chiasmata at diakinesis and metaphase I of meiosis. Electron microscopy of whole-mount surface-spread synaptonemal complex complements of pollen mother cell nuclei revealed that the achiasmate condition is probably due not only to the failure to complete synapsis, but also to the indiscriminate way in which the chromosomes form synaptonemal complexes during meiotic prophase. Synapsis begins and progresses with complete disregard to homology, with frequent exchanges of pairing partners resulting in the formation of multiple associations comprising heterologous chromosomes. Intrachromosomal synapsis is also evident as fold-back loops. Up to 78% of lateral element length is incorporated into synaptonemal complex, the morphology of which is not unlike that of normal A. fistulosum and other Allium species described previously. However, all the synaptonemal complexes are ineffective in terms of supporting chiasmata, since 16 univalents enter metaphase I and disjoin irregularly at anaphase I. The mutant is as a consequence completely male sterile. The synaptic behaviour observed confirms that the recognition of homology is an independent process and not a prerequisite for synaptonemal complex formation. It is hoped this mutant will be a valuable tool for probing the molecular basis of homology.

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Williamson, Hobart R., and Pesach Ben Yitzchak. "The synaptonemal complexes of Achlya recurva (Oomycetes): karyotype analysis and three-dimensional reconstruction of pachytene nuclei in antheridia and oogonia." Canadian Journal of Botany 69, no. 6 (June 1, 1991): 1384–95. http://dx.doi.org/10.1139/b91-178.

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Fifteen synaptonemal complexes, as determined by three-dimensional reconstruction of serial, ultrathin sections, were present within both antheridial and oogonial zygotene and pachytene nuclei of the oomyceteous fungus Achlya recurva, thus n = 15. The present study represents the first complete reconstruction of synaptonemal complexes in the genus Achlya. The occurrence of both zygonema and pachynema was simultaneous in antheridia and oogonia. Pachytene nuclei of antheridia and oogonia are small, 13 μm3 in volume, and the average length of the synaptonemal complexes ranged from 1.9 to 4.4 μm. Lateral elements at zygotene ranged from 1.2 to 4.7 μm. Both ends of each synaptonemal complex were attached randomly to the nuclear envelope, so a bouquet formation was not observed at pachytene. In A. recurva, the dimensions of the synaptonemal complex were as follows: overall width = 270 nm; the lateral elements = 75 nm each in width and the central region = 120 nm. There was no central element and associated transverse filaments, which may be associated with development of alternative reproductive strategies other than amphimixis, as in nematodes. Of the 15 synaptonemal complexes present, only the one carrying the nucleolus organizer region could be clearly identified from one nucleus to the next. The nucleolar organizer region was on the average 0.75 μm from the telomere in both zygotene and pachytene nuclei. There were an average of three recombination nodules in each nucleus. Synaptonemal complexes have been reported in over 80 different species of fungi and related protista. Karyotypic evolution in the oomycetes and fungi may be the result of poly-ploidization, followed by cytogenetic diversification involving aneuploidy and differing degrees of polyploidy. Such a sequence of events could explain the apparent polyphyletic formation of this group. Key words: karyotype, Oomycetes, pachytene, synaptonemal complexes, three-dimensional reconstruction.

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Braselton, James P. "Ultrastructural karyology of Spongospora subterranea (Plasmodiophoromycetes)." Canadian Journal of Botany 70, no. 6 (June 1, 1992): 1228–33. http://dx.doi.org/10.1139/b92-155.

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Sporogenic (cystogenous) stages of development of Spongospora subterranea (Wallroth) Lagerheim f.sp. subterranea Tomlinson infecting potato tubers were examined with transmission electron microscopy. Volume of nuclei in transitional Plasmodia was 28.2 ± 8.3 μm3. Serial section analysis revealed 37 synaptonemal complexes, hence the haploid chromosome number was considered to be 37. Total length of synaptonemal complexes per nucleus was 74.6 ± 1.4 μm, with individual synaptonemal complexes ranging in length from 1.34 ± 0.07 μm to 3.48 ± 0.17 μm. No polycomplexes were observed in transitional nuclei. Electron-opaque thickenings of lateral elements occurred irregularly. Additional ultrastructural features of sporogenic plasmodia included end-to-end paired centrioles defining the poles of the nuclei and a host–parasite boundary of a single unit membrane. Key words: karyotype, Plasmodiophoromycetes, Spongospora, synaptonemal complex.

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Chatterjee, R., and G. Jenkins. "Meiotic chromosome interactions in inbred autotetraploid rye (Secale cereale)." Genome 36, no. 1 (February 1, 1993): 131–38. http://dx.doi.org/10.1139/g93-016.

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Electron microscopy of whole-mount surface-spread synaptonemal complex complements and conventional light microscopy of chromosomes at first metaphase of meiosis were used to compare the relative frequencies of pairing configurations at the two stages in inbred autotetraploid rye (Secale cereale L.). Statistical tests showed significantly fewer multivalents at first metaphase than expectations based on random initiation of synapsis at each telomeric site within each group of four homologues. Direct observations of synaptic behaviour of chromosomes showed that this deviation is due primarily to a preponderance of bivalents during zygotene and pachytene. It is also the result of a significant drop in multivalent frequency from meiotic prophase to metaphase I, which is attributable both to a lack of chiasmata with which to consolidate multivalents and inhibition of chiasma formation in synaptonemal complex segments of multivalents that are nonhomologous.Key words: autotetraploid, rye, synaptonemal complex, multivalents, chiasmata.

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47

Maguire, M. P., R. W. Riess, and A. M. Paredes. "Evidence from a maize desynaptic mutant points to a probable role of synaptonemal complex central region components in provision for subsequent chiasma maintenance." Genome 36, no. 5 (October 1, 1993): 797–807. http://dx.doi.org/10.1139/g93-105.

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Homozygotes for the dsy1 desynaptic mutant of maize show massive failure of chiasma maintenance during diplotene and diakinesis. Although some chiasmata persist until anaphase I in most microsporocytes expressing this mutant, homozygotes are completely or nearly completely sterile, owing apparently to disjunctive irregularities. Pachytene synaptic errors and some synaptic failure also are found, but recombination nodules are common in homologously synapsed regions, and equational separation of a heterozygous knob into univalents or open arms at diakinesis clearly demonstrates that chiasma failure occurs following crossing-over. A wider than normal synaptonemal complex central region and uniform apparent weakness of central region cross connections to spreading procedures strongly suggest the presence of a genetic lesion in a synaptonemal complex central region component. The dsy1 mutant may provide an especially important source of material for molecular studies on the nature of chiasma maintenance mechanism.Key words: chiasma maintenance, synaptonemal complex, meiotic mutant.

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Maguire, M. P., A. M. Paredes, and R. W. Riess. "The desynaptic mutant of maize as a combined defect of synaptonemal complex and chiasma maintenance." Genome 34, no. 6 (December 1, 1991): 879–87. http://dx.doi.org/10.1139/g91-135.

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The phenotype of the desynaptic (dy) mutant of maize in microsporocytes at meiotic prophase was compared with normal microsporocytes of a closely related strain and with microsporocytes of a maize inbred line (KYS) assumed to be normal. Strikingly more univalents and open arms of bivalents were found in the mutant cells than in normal cells at diakinesis, and where there was heterozygosity for a distal knob (heterochromatic region), separation was usually equational, indicating the occurrence of normal crossing-over followed by failure of chiasma maintenance in the mutant. Differences found in the mutant by electron microscopy were a statistically significant wider dimension of the synaptonemal complex central region and also less twisting of synapsed configurations at pachytene. It is suggested that these are side-effect symptoms of a defect in the synaptonemal complex (or associated substance), which is expressed later as sporadic loss of chiasma maintenance.Key words: desynaptic, chiasma maintenance, synaptonemal complex.

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Albini, S. M., and G. H. Jones. "Synaptonemal complex spreading in Allium cepa and Allium fistulosum. II. Pachytene observations: the SC karyotype and the correspondence of late recombination nodules and chiasmata." Genome 30, no. 3 (June 1, 1988): 399–410. http://dx.doi.org/10.1139/g88-069.

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Pachytene synaptonemal complexes and recombination nodules were analysed, by surface spreading, in the closely related species Allium fistulosum and Allium cepa (both 2n = 16), which show highly contrasting patterns of chiasma distribution. Pachytene observations show that all eight pairs of homologues are fully paired in both species, despite the pronounced localisation of chiasmata in A. fistulosum. Synaptonemal complex karyotype analysis reveals similar marker complexes in both species. These are presumed homoeologues, which, possibly due to the uneven distribution of the higher DNA amount found in A. cepa, rank in slightly different positions in the two karyotypes. Darkly staining ellipsoidal late recombination nodules were observed associated with PTA stained pachytene synaptonemal complexes. The positional distribution of late recombination nodules along synaptonemal complexes corresponds almost exactly to the distribution of chiasmata along metaphase I bivalents in the two species. These observations strongly support the proposal that late recombination nodules are involved in reciprocal meiotic recombination. The frequencies of late recombination nodules at pachytene showed deficits (30% in A. fistulosum, 70% in A. cepa) compared to metaphase I chiasma frequencies. It is suggested that the greater deficit of late recombination nodules in A. fistulosum could be related to a longer duration of meiosis in this species resulting from its greater genomic DNA content.Key words: synaptonemal complex, recombination nodules, Allium.

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Dollin, A. E., J. D. Murray, and C. B. Gillies. "Synaptonemal complex analysis of hybrid cattle. I. Pachytene substaging and the normal full bloods." Genome 32, no. 5 (October 1, 1989): 856–64. http://dx.doi.org/10.1139/g89-522.

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Meiotic chromosome pairing abnormalities in full-blood and hybrid Bos taurus and B. indicus cattle have been surveyed by electron microscopy of pachytene synaptonemal complex spreads. In this paper, the full-blood spreads are described in detail, including the use of XY and nucleolar morphology and other measured parameters for pachytene substaging. Pairing abnormalities were observed in up to 9% of the full-blood spreads. Most of these pairing abnormalities (83%) occurred in early-pachytene spreads, suggesting that the mechanism of synaptic adjustment may operate in cattle.Key words: synaptonemal complex, cattle, pachytene substages.

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Journal articles on the topic 'Synaptonemal Complex'

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