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Crispr cas

In K Cho, Silun Wang, Hui Mao, Anthony Ws Chan
Recent advances in stem cell-based regenerative medicine, cell replacement therapy, and genome editing technologies (i.e. CRISPR-Cas 9) have sparked great interest in in vivo cell monitoring. Molecular imaging promises a unique approach to noninvasively monitor cellular and molecular phenomena, including cell survival, migration, proliferation, and even differentiation at the whole organismal level. Several imaging modalities and strategies have been explored for monitoring cell grafts in vivo. We begin this review with an introduction describing the progress in stem cell technology, with a perspective toward cell replacement therapy...
2016: American Journal of Nuclear Medicine and Molecular Imaging
Walter H Moos, Carl A Pinkert, Michael H Irwin, Douglas V Faller, Krishna Kodukula, Ioannis P Glavas, Kosta Steliou
Preclinical Research Approximately 2,500 years ago, Hippocrates used the word herpes as a medical term to describe lesions that appeared to creep or crawl on the skin, advocating heat as a possible treatment. During the last 50 years, pharmaceutical research has made great strides, and therapeutic options have expanded to include small molecule antiviral agents, protease inhibitors, preventive vaccines for a handful of the papillomaviruses, and even cures for hepatitis C virus infections. However, effective treatments for persistent and recurrent viral infections, particularly the highly prevalent herpesviruses, continue to represent a significant unmet medical need, affecting the majority of the world's population...
October 20, 2016: Drug Development Research
Liezhen Fu, Luan Wen, Nga Luu, Yun-Bo Shi
Genome editing with designer nucleases such as TALEN and CRISPR/Cas enzymes has broad applications. Delivery of these designer nucleases into organisms induces various genetic mutations including deletions, insertions and nucleotide substitutions. Characterizing those mutations is critical for evaluating the efficacy and specificity of targeted genome editing. While a number of methods have been developed to identify the mutations, none other than sequencing allows the identification of the most desired mutations, i...
October 17, 2016: Scientific Reports
Konstantin Kuznedelov, Vladimir Mekler, Sofia Lemak, Monika Tokmina-Lukaszewska, Kirill A Datsenko, Ishita Jain, Ekaterina Savitskaya, John Mallon, Sergey Shmakov, Brian Bothner, Scott Bailey, Alexander F Yakunin, Konstantin Severinov, Ekaterina Semenova
The Escherichia coli type I-E CRISPR-Cas system Cascade effector is a multisubunit complex that binds CRISPR RNA (crRNA). Through its 32-nucleotide spacer sequence, Cascade-bound crRNA recognizes protospacers in foreign DNA, causing its destruction during CRISPR interference or acquisition of additional spacers in CRISPR array during primed CRISPR adaptation. Within Cascade, the crRNA spacer interacts with a hexamer of Cas7 subunits. We show that crRNAs with a spacer length reduced to 14 nucleotides cause primed adaptation, while crRNAs with spacer lengths of more than 20 nucleotides cause both primed adaptation and target interference in vivo Shortened crRNAs assemble into altered-stoichiometry Cascade effector complexes containing less than the normal amount of Cas7 subunits...
October 13, 2016: Nucleic Acids Research
Knut J Egelie, Gregory D Graff, Sabina P Strand, Berit Johansen
No abstract text is available yet for this article.
October 11, 2016: Nature Biotechnology
Muhammad Abu Bakr Shabbir, Haihong Hao, Muhammad Zubair Shabbir, Hafiz Iftikhar Hussain, Zahid Iqbal, Saeed Ahmed, Adeel Sattar, Mujahid Iqbal, Jun Li, Zonghui Yuan
Prokaryotes have developed numerous innate immune mechanisms in order to fend off bacteriophage or plasmid attack. One of these immune systems is clustered regularly interspaced short palindromic repeats (CRISPR). CRISPR-associated proteins play a key role in survival of prokaryotes against invaders, as these systems cleave DNA of foreign genetic elements. Beyond providing immunity, these systems have significant impact in altering the bacterial physiology in term of its virulence and pathogenicity, as well as evolution...
2016: Frontiers in Immunology
Karen L Maxwell, Bianca Garcia, Joseph Bondy-Denomy, Diane Bona, Yurima Hidalgo-Reyes, Alan R Davidson
Bacterial CRISPR-Cas adaptive immune systems use small guide RNAs to protect against phage infection and invasion by foreign genetic elements. We previously demonstrated that a group of Pseudomonas aeruginosa phages encode anti-CRISPR proteins that inactivate the type I-F and I-E CRISPR-Cas systems using distinct mechanisms. Here, we present the three-dimensional structure of an anti-CRISPR protein and map a functional surface that is critical for its potent inhibitory activity. The interaction of the anti-CRISPR protein with the CRISPR-Cas complex through this functional surface is proposed to prevent the binding of target DNA...
October 11, 2016: Nature Communications
Rongfang Xu, Pengcheng Wei, Jianbo Yang
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) system is a newly emerging mutagenesis (gene-editing) tool in genetic engineering. Among the agriculturally important crops, several genes have been successfully mutated by the system, and some agronomic important traits have been rapidly generated, which indicates the potential applications in both scientific research and plant breeding. In this chapter, we describe a standard gene-editing procedure to effectively target rice genes and to make specific rice mutants using the CRISPR/Cas9 system mediated by Agrobacterium transformation...
2017: Methods in Molecular Biology
Forrest C Walker, Lucy Chou-Zheng, Jack A Dunkle, Asma Hatoum-Aslan
CRISPR-Cas (Clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) is a prokaryotic immune system that destroys foreign nucleic acids in a sequence-specific manner using Cas nucleases guided by short RNAs (crRNAs). Staphylococcus epidermidis harbours a Type III-A CRISPR-Cas system that encodes the Cas10-Csm interference complex and crRNAs that are subjected to multiple processing steps. The final step, called maturation, involves a concerted effort between Csm3, a ruler protein in Cas10-Csm that measures six-nucleotide increments, and the activity of a nuclease(s) that remains unknown...
October 3, 2016: Nucleic Acids Research
Magdalena Hryhorowicz, Daniel Lipiński, Joanna Zeyland, Ryszard Słomski
CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) adaptive immune systems constitute a bacterial defence against invading nucleic acids derived from bacteriophages or plasmids. This prokaryotic system was adapted in molecular biology and became one of the most powerful and versatile platforms for genome engineering. CRISPR/Cas9 is a simple and rapid tool which enables the efficient modification of endogenous genes in various species and cell types. Moreover, a modified version of the CRISPR/Cas9 system with transcriptional repressors or activators allows robust transcription repression or activation of target genes...
October 3, 2016: Archivum Immunologiae et Therapiae Experimentalis
Kazuo Nakajima, An-A Kazuno, John Kelsoe, Moe Nakanishi, Toru Takumi, Tadafumi Kato
Knockin (KI) mouse carrying a point mutation has been an invaluable tool for disease modeling and analysis. Genome editing technologies using the CRISPR/Cas system has emerged as an alternative way to create KI mice. However, if the mice carry nucleotide insertions and/or deletions (InDels) in other genes, which could have unintentionally occurred during the establishment of the KI mouse line and potentially have larger impact than a point mutation, it would confound phenotyping of the KI mice. In this study, we performed whole exome sequencing of multiple lines of F1 heterozygous Ntrk1 KI mice generated using the CRISPR/Cas system in comparison to that of a wild-type mouse used as a control...
October 4, 2016: Scientific Reports
Dacheng Ma, Shuguang Peng, Zhen Xie
Programmable and precise regulation of dCas9 functions in response to multiple molecular signals by using synthetic gene circuits will expand the application of the CRISPR-Cas technology. However, the application of CRISPR-Cas therapeutic circuits is still challenging due to the restrictive cargo size of existing viral delivery vehicles. Here, we construct logic AND circuits by integrating multiple split dCas9 domains, which is useful to reduce the size of synthetic circuits. In addition, we engineer sensory switches by exchanging split dCas9 domains, allowing differential regulations on one gene, or activating two different genes in response to cell-type specific microRNAs...
October 3, 2016: Nature Communications
Raymond H J Staals, Simon A Jackson, Ambarish Biswas, Stan J J Brouns, Chris M Brown, Peter C Fineran
CRISPR-Cas systems provide bacteria with adaptive immunity against foreign nucleic acids by acquiring short, invader-derived sequences called spacers. Here, we use high-throughput sequencing to analyse millions of spacer acquisition events in wild-type populations of Pectobacterium atrosepticum. Plasmids not previously encountered, or plasmids that had escaped CRISPR-Cas targeting via point mutation, are used to provoke naive or primed spacer acquisition, respectively. The origin, location and order of spacer acquisition show that spacer selection through priming initiates near the site of CRISPR-Cas recognition (the protospacer), but on the displaced strand, and is consistent with 3'-5' translocation of the Cas1:Cas2-3 acquisition machinery...
October 3, 2016: Nature Communications
Michael A Goodman, Donya Moradi Manesh, Punam Malik, Marc E Rothenberg
No abstract text is available yet for this article.
September 30, 2016: Expert Review of Clinical Immunology
Frank Hille, Emmanuelle Charpentier
Prokaryotes have evolved several defence mechanisms to protect themselves from viral predators. Clustered regularly interspaced short palindromic repeats (CRISPR) and their associated proteins (Cas) display a prokaryotic adaptive immune system that memorizes previous infections by integrating short sequences of invading genomes-termed spacers-into the CRISPR locus. The spacers interspaced with repeats are expressed as small guide CRISPR RNAs (crRNAs) that are employed by Cas proteins to target invaders sequence-specifically upon a reoccurring infection...
November 5, 2016: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Andrew McDowell, Emma Barnard, Jared Liu, Huiying Li, Sheila Patrick
Recently, strains of Propionibacterium acnes from the type III genetic division have been proposed as Propionibacterium acnes subsp. elongatum subsp. nov., with strains from the type I and II divisions collectively classified as Propionibacterium acnes subsp. acnes subsp. nov. Under such a taxonomic re-appraisal, we believe that types I and II should also have their own separate rank of subspecies. In support of this, we describe a polyphasic taxonomic study based on the analysis of publically available multilocus and whole genome sequence datasets, alongside a systematic review of previously published phylogenetic, genomic, phenotypic and clinical data...
September 25, 2016: International Journal of Systematic and Evolutionary Microbiology
Alexandra East-Seletsky, Mitchell R O'Connell, Spencer C Knight, David Burstein, Jamie H D Cate, Robert Tjian, Jennifer A Doudna
Bacterial adaptive immune systems use CRISPRs (clustered regularly interspaced short palindromic repeats) and CRISPR-associated (Cas) proteins for RNA-guided nucleic acid cleavage. Although most prokaryotic adaptive immune systems generally target DNA substrates, type III and VI CRISPR systems direct interference complexes against single-stranded RNA substrates. In type VI systems, the single-subunit C2c2 protein functions as an RNA-guided RNA endonuclease (RNase). How this enzyme acquires mature CRISPR RNAs (crRNAs) that are essential for immune surveillance and how it carries out crRNA-mediated RNA cleavage remain unclear...
September 26, 2016: Nature
Alexander Brown, Wendy S Woods, Pablo Perez-Pinera
The discovery of the prokaryotic CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) system and its adaptation for targeted manipulation of DNA in diverse species has revolutionized the field of genome engineering. In particular, the fusion of catalytically inactive Cas9 to any number of transcriptional activator domains has resulted in an array of easily customizable synthetic transcription factors that are capable of achieving robust, specific, and tunable activation of target gene expression within a wide variety of tissues and cells...
2017: Methods in Molecular Biology
A F Mentis
Down syndrome (DS; trisomy 21), the commonest genetic cause of mental disability, affects approximately 250,000 families in the United States alone. Despite milestones in understanding the specific genetic causes of the syndrome, the major symptoms of DS - not least those related to neurocognitive function - are incurable. DS phenotypes are highly variable, and gene expression patterns cannot be explained by trisomy alone, implicating epigenetics in DS pathophysiology. DNA and histone modifications appear to contribute to DS pathology and cognitive defects, and epigenomic, and genome editing research have very recently opened up novel therapeutic avenues for several diseases including DS...
September 16, 2016: Neuroscience and Biobehavioral Reviews
Sergey Lekomtsev, Sofia Aligianni, Ana Lapao, Tilmann Bürckstümmer
BACKGROUND: Chromosomal translocations are a hallmark of cancer cells and give rise to fusion oncogenes. To gain insight into the mechanisms governing tumorigenesis, adequate model cell lines are required. RESULTS: We employ the versatile CRISPR/Cas system to engineer cell lines in which chromosomal translocations are either generated de novo (CD74-ROS1) or existing translocations are reverted back to the original configuration (BCR-ABL1). To this end, we co-apply two guide RNAs to artificially generate two breakpoints and screen for spontaneous fusion events by PCR...
2016: BMC Genomics
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