Academic literature on the topic 'CRISPR system'

Clustered regularly interspaced short palindromic repeats/CRISPR-associated CRISPER/Cas system, as the current most popular gene-editing technology, shows great advantages of simple composition, good specificity and high cutting efficiency compared with other gene editing technology. With the rapid development of CRISPR-Cas systems, such as Cas9, Cas12a and Cas12f, can be used to edit the DNA of eukaryotic cells, and then successively found that Cas13a, Cas13b and Cas13d are targeted to the RNA merons. Through various modifications, scientists also developed a new type of the CRISPR-Cas system. With higher DNA-cutting activity, greater specificity, and smaller size than the natural CRISPR system, these engineered gene-editing systems form a powerful tool set for DNA sequence knockout, replacement, epigenetic editing, and even the activation and suppression of gene expression. Despite the potential problems in the practical application of CRISPR technology to be solved, it is believed that with further improvement, the CRISPR treatment technology will play a more important role in the prevention and treatment of human diseases, more perfectly and precisely. This review introduces the structure, functional mechanism and application of CRISPR/Cas system in human genetic diseases, and the current status and development of CRISPR/Cas system are summarized and prospected.

The CRISPRs (clustered regularly interspaced short palindromic repeats) and their associated Cas (CRISPR-associated) proteins are a prokaryotic adaptive defence system against foreign nucleic acids. The CRISPR array comprises short repeats flanking short segments, called ‘spacers’, which are derived from foreign nucleic acids. The process of spacer insertion into the CRISPR array is termed ‘adaptation’. Adaptation allows the system to rapidly evolve against emerging threats. In the present article, we review the most recent studies on the adaptation process, and focus primarily on the subtype I-E CRISPR–Cas system of Escherichia coli.

ABSTRACTCRISPR (clustered regularly interspaced short palindromic repeat)-Cas (CRISPR-associated protein) systems are diverse and found in many archaea and bacteria. These systems have mainly been characterized as adaptive immune systems able to protect against invading mobile genetic elements, including viruses. The first step in this protection is acquisition of spacer sequences from the invader DNA and incorporation of those sequences into the CRISPR array, termed CRISPR adaptation. Progress in understanding the mechanisms and requirements of CRISPR adaptation has largely been accomplished using overexpression ofcasgenes or plasmid loss assays; little work has focused on endogenous CRISPR-acquired immunity from viral predation. Here, we developed a new biofilm-based assay system to enrich forPseudomonas aeruginosastrains with new spacer acquisition. We used this assay to demonstrate thatP. aeruginosarapidly acquires spacers protective against DMS3vir, an engineered lytic variant of the Mu-like bacteriophage DMS3, through primed CRISPR adaptation from spacers present in the native CRISPR2 array. We found that for theP. aeruginosatype I-F system, thecas1gene is required for CRISPR adaptation,recGcontributes to (but is not required for) primed CRISPR adaptation,recDis dispensable for primed CRISPR adaptation, and finally, the ability of a putative priming spacer to prime can vary considerably depending on the specific sequences of the spacer.IMPORTANCEOur understanding of CRISPR adaptation has expanded largely through experiments in type I CRISPR systems using plasmid loss assays, mutants ofEscherichia coli, orcas1-cas2overexpression systems, but there has been little focus on studying the adaptation of endogenous systems protecting against a lytic bacteriophage. Here we describe a biofilm system that allowsP. aeruginosato rapidly gain spacers protective against a lytic bacteriophage. This approach has allowed us to probe the requirements for CRISPR adaptation in the endogenous type I-F system ofP. aeruginosa. Our data suggest that CRISPR-acquired immunity in a biofilm may be one reason that manyP. aeruginosastrains maintain a CRISPR-Cas system.

Borna disease virus (BoDV-1) is a bornavirus that infects the central nervous systems of various animal species, including humans, and causes fatal encephalitis. BoDV-1 also establishes persistent infection in neuronal cells and causes neurobehavioral abnormalities. Once neuronal cells or normal neural networks are lost by BoDV-1 infection, it is difficult to regenerate damaged neural networks. Therefore, the development of efficient anti-BoDV-1 treatments is important to improve the outcomes of the infection. Recently, one of the clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) systems, CRISPR/Cas13, has been utilized as antiviral tools. However, it is still unrevealed whether the CRISPR/Cas13 system can suppress RNA viruses in persistently infected cells. In this study, we addressed this question using persistently BoDV-1-infected cells. The CRISPR/Cas13 system targeting viral mRNAs efficiently decreased the levels of target viral mRNAs and genomic RNA (gRNA) in persistently infected cells. Furthermore, the CRISPR/Cas13 system targeting viral mRNAs also suppressed BoDV-1 infection if the system was introduced prior to the infection. Collectively, we demonstrated that the CRISPR/Cas13 system can suppress BoDV-1 in both acute and persistent infections. Our findings will open the avenue to treat prolonged infection with RNA viruses using the CRISPR/Cas13 system.