Major and minor crRNA annealing sites facilitate low stringency DNA protospacer binding prior to Type I-A CRISPR-Cas interference in Sulfolobus.

ABSTRACT: The stringency of crRNA-protospacer DNA base pair matching required for effective CRISPR-Cas interference is relatively low in crenarchaeal Sulfolobus species in contrast to that required in some bacteria. To understand its biological significance we studied crRNA-protospacer interactions in Sulfolobus islandicus REY15A which carries multiple, and functionally diverse, interference complexes. A range of mismatches were introduced into a vector-borne protospacer that was identical to spacer 1 of CRISPR locus 2, with a cognate CCN PAM sequence. Two important crRNA annealing regions were identified on the 39 bp protospacer, a strong primary site centered on nucleotides 3 - 7 and a weaker secondary site at nucleotides 21 - 25. Multiple mismatches introduced into remaining protospacer regions d

SUBMITTER: Mousaei M 

PROVIDER: S-EPMC5100340 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature