The CRISPR arrays found in many bacteria and most archaea are transcribed into a long precursor RNA that is processed into small clustered regularly interspaced short palindromic repeats (CRISPR) RNAs (crRNAs). These RNA molecules can contain fragments of viral genomes and mediate, together with a set of CRISPR-associated (Cas) proteins, the prokaryotic immunity against viral attacks. CRISPR/Ca...

Amlinger, L. 2017. The type I-E CRISPR-Cas system. Biology and applications of an adaptive immune system in bacteria. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1466. 61 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9787-3. CRISPR-Cas systems are adaptive immune systems in bacteria and archaea, consisting of a clustered reg...

Seminal studies showed that CRISPR-Cas systems provide adaptive immunity in prokaryotes and promising gene-editing tools from bacteria to humans. Yet, reports diverged on whether some CRISPR systems naturally target DNA or RNA. Here, Samai and colleagues unify the studies, showing that a single type III CRISPR-Cas system cleaves both DNA and RNA targets, independently.

UNLABELLED Clustered regularly interspaced short palindromic repeat (CRISPR) loci encode an adaptive immune system of prokaryotes. Within these loci, sequences intercalated between repeats known as "spacers" specify the targets of CRISPR immunity. The majority of spacers match sequences present in phages and plasmids; however, it is not known whether there are differences in the immunity provid...

MOTIVATION The discovery of CRISPR-Cas systems almost 20 years ago rapidly changed our perception of the bacterial and archaeal immune systems. CRISPR loci consist of several repetitive DNA sequences called repeats, inter-spaced by stretches of variable length sequences called spacers. This CRISPR array is transcribed and processed into multiple mature RNA species (crRNAs). A single crRNA is in...

UNLABELLED Clostridium difficile is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape C. difficile genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associ...

We determined the genetic maps of the megaplasmids of six neutoroxigenic Clostridium butyricum type E strains from Italy using molecular and bioinformatics techniques. The megaplasmids are circular, not linear as we had previously proposed. The differently-sized megaplasmids share a genetic region that includes structural, metabolic and regulatory genes. In addition, we found that a 168 kb gene...

Prokaryotic organisms survive under constant pressure of viruses. CRISPR-Cas system provides its prokaryotic host with an adaptive immune defense against viruses that have been previously encountered. It consists of two components: Cas-proteins that cleave the foreign DNA and CRISPR array that suits as a virus recognition key. CRISPR array consists of a series of spacers, short pieces of DNA th...

Cas1 integrase is the key enzyme of the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas adaptation module that mediates acquisition of spacers derived from foreign DNA by CRISPR arrays. In diverse bacteria, the cas1 gene is fused (or adjacent) to a gene encoding a reverse transcriptase (RT) related to group II intron RTs. An RT-Cas1 fusion protein has been recently shown t...

The methods based on the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system have quickly gained popularity for genome editing and transcriptional regulation in many organisms, including yeast. This review aims to provide a comprehensive overview of CRISPR application for different yeast species: from basic principles and genetic design to applicati...