Primary processing of CRISPR RNA by the endonuclease Cas6 in Staphylococcus epidermidis

FEBS Lett. 2015 Oct 7;589(20 Pt B):3197-204. doi: 10.1016/j.febslet.2015.09.005. Epub 2015 Sep 10.

Abstract

In many bacteria and archaea, an adaptive immune system (CRISPR-Cas) provides immunity against foreign genetic elements. This system uses CRISPR RNAs (crRNAs) derived from the CRISPR array, along with CRISPR-associated (Cas) proteins, to target foreign nucleic acids. In most CRISPR systems, endonucleolytic processing of crRNA precursors (pre-crRNAs) is essential for the pathway. Here we study the Cas6 endonuclease responsible for crRNA processing in the Type III-A CRISPR-Cas system from Staphylococcus epidermidis RP62a, a model for Type III-A CRISPR-Cas systems, and define substrate requirements for SeCas6 activity. We find that SeCas6 is necessary and sufficient for full-length crRNA biogenesis in vitro, and that it relies on both sequence and stem-loop structure in the 3' half of the CRISPR repeat for recognition and processing.

Keywords: CRISPR; CRISPR-associated; Cas6; Clustered regularly interspaced short palindromic repeats; RNA processing.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • CRISPR-Cas Systems / genetics*
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics*
  • Electrophoresis, Polyacrylamide Gel
  • Endonucleases / genetics*
  • Endonucleases / metabolism
  • Models, Genetic
  • Nucleic Acid Conformation
  • RNA / chemistry
  • RNA / genetics*
  • RNA / metabolism
  • RNA Precursors / genetics
  • RNA Precursors / metabolism
  • Staphylococcus epidermidis / genetics*
  • Staphylococcus epidermidis / metabolism
  • Substrate Specificity

Substances

  • Bacterial Proteins
  • RNA Precursors
  • RNA
  • Endonucleases