Distribution of CRISPR spacer matches in viruses and plasmids of crenarchaeal acidothermophiles and implications for their inhibitory mechanism.
Transcripts from spacer sequences within chromosomal repeat clusters [CRISPRs (clusters of regularly interspaced palindromic repeats)] from archaea have been implicated in inhibiting or regulating the propagation of archaeal viruses and plasmids. For the crenarchaeal thermoacidophiles, the chromosomal spacers show a high level of matches ( approximately 30%) with viral or plasmid genomes. Moreover, their distribution along the virus/plasmid genomes, as well as their DNA strand specificity, appear to be random. This is consistent with the hypothesis that chromosomal spacers are taken up directly and randomly from virus and plasmid DNA and that the spacer transcripts target the genomic DNA of the extrachromosomal elements and not their transcripts.
Shah
Shiraz Ali
SA
Centre for Comparative Genomics, Department of Biology, Biocenter, Copenhagen University, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
Hansen
Niels R
NR
Garrett
Roger A
RA
D002875:Chromosomes / Q000235:genetics; D019615:Crenarchaeota / Q000235:genetics*; D021901:DNA, Intergenic / Q000235:genetics*; D020745:Genome, Archaeal; D055029:Inverted Repeat Sequences / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D014780:Viruses / Q000235:genetics*
D021901:DNA, Intergenic