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Crispr cas

Winston X Yan, Shaorong Chong, Huaibin Zhang, Kira S Makarova, Eugene V Koonin, David R Cheng, David A Scott
Bacterial class 2 CRISPR-Cas systems utilize a single RNA-guided protein effector to mitigate viral infection. We aggregated genomic data from multiple sources and constructed an expanded database of predicted class 2 CRISPR-Cas systems. A search for novel RNA-targeting systems identified subtype VI-D, encoding dual HEPN domain-containing Cas13d effectors and putative WYL-domain-containing accessory proteins (WYL1 and WYL-b1 through WYL-b5). The median size of Cas13d proteins is 190 to 300 aa smaller than that of Cas13a-Cas13c...
March 9, 2018: Molecular Cell
Silvana Konermann, Peter Lotfy, Nicholas J Brideau, Jennifer Oki, Maxim N Shokhirev, Patrick D Hsu
Class 2 CRISPR-Cas systems endow microbes with diverse mechanisms for adaptive immunity. Here, we analyzed prokaryotic genome and metagenome sequences to identify an uncharacterized family of RNA-guided, RNA-targeting CRISPR systems that we classify as type VI-D. Biochemical characterization and protein engineering of seven distinct orthologs generated a ribonuclease effector derived from Ruminococcus flavefaciens XPD3002 (CasRx) with robust activity in human cells. CasRx-mediated knockdown exhibits high efficiency and specificity relative to RNA interference across diverse endogenous transcripts...
March 8, 2018: Cell
Hamid Reza Mirzaei, Hossein Pourghadamyari, Majid Rahmati, Abbas Mohammadi, Javid Sadri Nahand, Abbas Rezaei, Hamed Mirzaei, Jamshid Hadjati
Recently clinical trials utilizing genetically engineered T cells expressing a chimeric antigen receptor (CAR) that is half monoclonal antibody and half T-cell receptor have demonstrated remarkable response in patients with advanced cancers like relapsed or refractory acute lymphoblastic leukemia (ALL) and lymphoma. Moreover, emerging chimeric genome editing tools such as zinc-finger nucleases (ZNFs), transcription activator-like effector nucleases (TALENs) and clustered regulatory interspaced short palindromic repeat (CRISPR)/Cas composed of sequence-specific DNA binding module(s) linked to a non-specific DNA cleavage domain have made possible to dramatically expand the ability to manipulate cells aim to treat and/or study a wide range of diseases including cancer...
March 12, 2018: Cancer Letters
Michael W Deem, Melia Elizabeth Bonomo
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) constitute a multi-functional, constantly evolving immune system in bacteria and archaea cells. A heritable, molecular memory is generated of phage, plasmids, or other mobile genetic elements that attempt to attack the cell. This memory is used to recognize and interfere with subsequent invasions from the same genetic elements. This versatile prokaryotic tool has also been used to advance applications in biotechnology...
March 15, 2018: Physical Biology
Katia Tarasava, Rongming Liu, Andrew Garst, Ryan T Gill
Optimization of metabolic flux is a difficult and time-consuming process that often involves changing the expression levels of multiple genes simultaneously. While some pathways have a known rate limiting step, more complex metabolic networks can require a trial-and-error approach of tuning the expression of multiple genes to achieve a desired distribution of metabolic resources. Here we present an efficient method for generating expression diversity on a combinatorial scale using CRISPR interference. We use a modified native Escherichia coli Type I-E CRISPR-Cas system and an iterative cloning strategy for construction of guide RNA arrays...
March 14, 2018: Biotechnology and Bioengineering
Jie Zhang, Wenming Zong, Wei Hong, Zhong-Tian Zhang, Yi Wang
Although CRISPR-Cas9/Cpf1 have been employed as powerful genome engineering tools, heterologous CRISPR-Cas9/Cpf1 are often difficult to introduce into bacteria and archaea due to their severe toxicity. Since most prokaryotes harbor native CRISPR-Cas systems, genome engineering can be achieved by harnessing these endogenous immune systems. Here, we report the exploitation of Type I-B CRISPR-Cas of Clostridium tyrobutyricum for genome engineering. In silico CRISPR array analysis and plasmid interference assay revealed that TCA or TCG at the 5'-end of the protospacer was the functional protospacer adjacent motif (PAM) for CRISPR targeting...
March 9, 2018: Metabolic Engineering
Anna Maikova, Johann Peltier, Pierre Boudry, Eliane Hajnsdorf, Nicolas Kint, Marc Monot, Isabelle Poquet, Isabelle Martin-Verstraete, Bruno Dupuy, Olga Soutourina
Clostridium difficile, a major human enteropathogen, must cope with foreign DNA invaders and multiple stress factors inside the host. We have recently provided an experimental evidence of defensive function of the C. difficile CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system important for its survival within phage-rich gut communities. Here, we describe the identification of type I toxin-antitoxin (TA) systems with the first functional antisense RNAs in this pathogen...
February 26, 2018: Nucleic Acids Research
Pavel Bashtrykov, Albert Jeltsch
The discovery and adaptation of the CRISPR/Cas system for epigenome editing has allowed for a straightforward design of targeting modules which can direct epigenetic editors to virtually any genomic site. This advancement in DNA-targeting technology brings allele-specific epigenome editing into reach, a "super-specific" variation of epigenome editing whose goal is an alteration of chromatin marks at only one selected allele of the target genomic locus. This technology would be useful for the treatment of diseases caused by a mutant allele with a dominant effect, because allele-specific epigenome editing allows the specific silencing of the mutated allele leaving the healthy counterpart expressed...
2018: Methods in Molecular Biology
Charlene Babra Waryah, Colette Moses, Mahira Arooj, Pilar Blancafort
The completion of genome, epigenome, and transcriptome mapping in multiple cell types has created a demand for precision biomolecular tools that allow researchers to functionally manipulate DNA, reconfigure chromatin structure, and ultimately reshape gene expression patterns. Epigenetic editing tools provide the ability to interrogate the relationship between epigenetic modifications and gene expression. Importantly, this information can be exploited to reprogram cell fate for both basic research and therapeutic applications...
2018: Methods in Molecular Biology
Marianne G Rots, Albert Jeltsch
The introduction of CRISPR/Cas has resulted in a strong impulse for the field of gene-targeted epigenome reprogramming. In this approach EpiEditors are applied in cells, which consist of a DNA-binding part for targeting and a functional part to induce chromatin modifications at targeted genome loci. The accumulating evidence of epigenetic reprogramming of a given genomic locus resulting in gene expression changes indicated causal relationships of epigenetic marks instructing gene expression and opened the field for mainstream applications...
2018: Methods in Molecular Biology
Haiyan Zeng, Jumei Zhang, Qingping Wu, Wenjing He, Haoming Wu, Yingwang Ye, Chengsi Li, Na Ling, Moutong Chen, Juan Wang, Shuzhen Cai, Tao Lei, Yu Ding, Liang Xue
Cronobacter strains harboring the CRISPR-Cas system are important foodborne pathogens causing serious neonatal infections. However, the specific role of the CRISPR-Cas system in bacterial evolution remains relatively unexplored. In this study, we investigated the impact of CRISPR-Cas in Cronobacter evolution and obtained 137 new whole-genome sequences of Cronobacter by next-generation sequencing technology. Among the strains examined (n=240), 90.6% (193/213) of prevalent species Cronobacter sakazakii , Cronobacter malonaticus , and Cronobacter dublinensis strains had intact CRISPR-Cas systems...
March 9, 2018: Applied and Environmental Microbiology
Gal Ofir, Rotem Sorek
Bacteriophages, discovered about a century ago, have been pivotal as models for understanding the fundamental principles of molecular biology. While interest in phage biology declined after the phage "golden era," key recent developments, including advances in phage genomics, microscopy, and the discovery of the CRISPR-Cas anti-phage defense system, have sparked a renaissance in phage research in the past decade. This review highlights recently discovered unexpected complexities in phage biology, describes a new arsenal of phage genes that help them overcome bacterial defenses, and discusses advances toward documentation of the phage biodiversity on a global scale...
March 8, 2018: Cell
Frank Hille, Hagen Richter, Shi Pey Wong, Majda Bratovič, Sarah Ressel, Emmanuelle Charpentier
In bacteria and archaea, clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins constitute an adaptive immune system against phages and other foreign genetic elements. Here, we review the biology of the diverse CRISPR-Cas systems and the major progress achieved in recent years in understanding the underlying mechanisms of the three stages of CRISPR-Cas immunity: adaptation, crRNA biogenesis, and interference. The ecology and regulation of CRISPR-Cas in the context of phage infection, the roles of these systems beyond immunity, and the open questions that propel the field forward are also discussed...
March 8, 2018: Cell
Navish Kumar Batchu, Shradha Khater, Sonal Patil, Vinod Nagle, Gautam Das, Bhaskar Bhadra, Ajit Sapre, Santanu Dasgupta
A filamentous cyanobacteria, Geitlerinema sp. FC II, was isolated from marine algae culture pond at Reliance Industries Limited (RIL), India. The 6.7 Mb draft genome of FC II encodes for 6697 protein coding genes. Analysis of the whole genome sequence revealed presence of nif gene cluster, supporting its capability to fix atmospheric nitrogen. FC II genome contains two variants of sulfide:quinone oxidoreductases (SQR), which is a crucial elector donor in cyanobacterial metabolic processes. FC II is characterized by the presence of multiple CRISPR- Cas (Clustered Regularly Interspaced Short Palindrome Repeats - CRISPR associated proteins) clusters, multiple variants of genes encoding photosystem reaction centres, biosynthetic gene clusters of alkane, polyketides and non-ribosomal peptides...
March 5, 2018: Genomics
Hannah G Hampton, Simon A Jackson, Robert D Fagerlund, Anne I M Vogel, Ron L Dy, Tim R Blower, Peter C Fineran
Bacteria resist phage infection using multiple strategies, including CRISPR-Cas and abortive infection (Abi) systems. Abi systems provide population-level protection from phage predation, via "altruistic" cell suicide. It has recently been shown that some Abi systems function via a toxin-antitoxin (TA) mechanism, such as the widespread AbiE family. The Streptococcus agalactiae AbiE system consists of a bicistronic operon encoding the AbiEi antitoxin and AbiEii toxin, which function as a Type IV TA system...
March 5, 2018: Journal of Molecular Biology
Rabea Jesser, Juliane Behler, Christian Benda, Viktoria Reimann, Wolfgang R Hess
Specialized RNA endonucleases are critical for efficient activity of the CRISPR-Cas defense mechanisms against invading DNA or RNA. Cas6-type enzymes are the RNA endonucleases in many type I and type III CRISPR-Cas systems. These enzymes are diverse and critical residues involved in the recognition and cleavage of RNA substrates are not universally conserved. Cas6 endonucleases associated with the CRISPR-Cas subtypes I-A, I-B, I-C, I-E and I-F, as well as III-B have been studied from four archaea and three bacteria thus far...
March 8, 2018: RNA Biology
Mengyuan Hao, Yanhua Cui, Xiaojun Qu
CRISPR-Cas (Clustered regularly interspaced short palindromic repeats-CRISPR associated proteins) loci, which provide a specific immunity against exogenous elements, are hypervariable among distinct prokaryotes. Based on previous researches, this review focuses on concluding systematical genome editing protocols in Streptococcus thermophilus. Firstly, its protocols and optimized conditions in gene editing are introduced. What's more, classification and diversity analyses of S. thermophilus CRISPR-Cas benefit the further understanding of evolution relationship among Streptococcus...
2018: Frontiers in Microbiology
Florian Noack, Federico Calegari
Epigenetic modifications of DNA and chromatin are long known to control stem cell differentiation and organ function but the role of similar modifications at the level or regulatory RNAs is just beginning to emerge. Over 160 RNA modifications have been identified but their abundance, distribution and functional significance are not known. The few available maps of RNA modifications indicated their dynamic regulation during somatic stem cell differentiation, brain development and function in adulthood suggesting a hitherto unsuspected layer of regulation both at the level of RNA metabolism and post-transcriptional control of gene expression...
2018: Frontiers in Neuroscience
Fei He, Yuvaraj Bhoobalan-Chitty, Lan B Van, Anders L Kjeldsen, Matteo Dedola, Kira S Makarova, Eugene V Koonin, Ditlev E Brodersen, Xu Peng
Viruses employ a range of strategies to counteract the prokaryotic adaptive immune system, clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas), including mutational escape and physical blocking of enzymatic function using anti-CRISPR proteins (Acrs). Acrs have been found in many bacteriophages but so far not in archaeal viruses, despite the near ubiquity of CRISPR-Cas systems in archaea. Here, we report the functional and structural characterization of two archaeal Acrs from the lytic rudiviruses, SIRV2 and SIRV3...
March 5, 2018: Nature Microbiology
Jianqiang Yang, Ning Yi, Junhui Zhang, Wen He, Di He, Wanwan Wu, Shuyang Xu, Feng Li, Guoping Fan, Xianmin Zhu, Zhigang Xue, Wensheng Zhou
Thyroid stimulating hormone receptor (TSHR), a G-protein-coupled receptor, is important for thyroid development and growth. In several cases, frameshift and/or nonsense mutations in TSHR were found in the patients with congenital hypothyroidism (CH), however they have not been functionally studied in an animal model. In the present work, we generated a unique TshrDf/Df rat model that recapitulates the phenotypes in TSHR Y444X patient by CRISPR/Cas genome editing technology. In this rat model, TSHR is truncated at the second transmembrane domain, leading to CH phenotypes as what was observed in the patients, including dwarf, thyroid aplasia, infertility, TSH resistant as well as low serum thyroid hormone levels...
March 5, 2018: Scientific Reports
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