Csy4 is responsible for CRISPR RNA processing in Pectobacterium atrosepticum
Abstract
Bacteria have various mechanisms to defend themselves against phage attack including restriction enzymes and abortive infection (1,2). The recently discovered CRISPR (clustered, regularly interspaced short palindromic repeat)/Cas (CRISPR-associated) represents a new defense mechanism that acts via small ncRNAs and equips bacteria with a heritable "acquired immune system" against infection by extrachromosomal agents (3,4). This system operates in at least two stages with (1) an adaption stage, at which spacers from foreign genetic material are incorporated into the CRISPR locus and (2) an interference stage, where the CRISPR/Cas system acts on the invading nucleic acid. The interference stage involves the generation of small guide RNAs (crRNAs) (5,6) that, in combination with Cas proteins, recognize and inhibit foreign nucleic acids in a sequence specific manner. Here we have characterized the Ypest subtype CRISPR/Cas system in the plant pathogen Pectobacterium atrosepticum. We present our results on the transcriptional activity of this CRISPR/Cas locus and furthermore on the processing of the CRISPR RNAs by Csy4.
References
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