César Díez-Villaseñor

TL;DR: It is shown that the conservation of proto-spacer adjacent motifs (PAMs) is a common theme for the most diverse CRISPR systems, implying that there is aCRISPR-type-specific (motif-directed) choice of the spacers, which subsequently determines the interference target.

TL;DR: The SRSRs are widespread among the various physiological and phylogenetic groups, probably being present in all the Archaea and hyperthermophilic Bacteria, in at least some members of the cyanobacteria and proteobacteria lineages, as well as in the two subgroups of Gram-positive bacteria (the low and high GC content groups).

TL;DR: The data suggest that the degeneration of one CRISPR/CAS system in E. coli ancestors could have been brought about by self-interference, and substantiate different levels of activity between loci of both CRISpr types, as well as different target preferences andCRISPR relevances for particular groups of strains.

TL;DR: This work describes the development and application in Escherichia coli strains of an interference-independent assay based on engineered selectable CRISPR-spacer integration reporter plasmids and confirmed fundamental aspects of this process such as the critical requirement of Cas1 and Cas2 and the identity of the CTT protospacer motif for the E. coli K12 system.

TL;DR: It is shown that natural CRISPR-mediated immunity against invading DNA occurs in wild type Escherichia coli and it is demonstrated that positions next to the PAM in invading DNA influence their recognition and degradation by these prokaryotic immune systems.