Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 288, Issue 39, Pages 27888-27897Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M113.499244
Keywords
-
Categories
Funding
- Helmsley Postdoctoral Fellowship for Basic and Translational Research on Disorders of the Digestive System at The Rockefeller University
- Searle Scholars Program
- Rita Allen Scholars Program
- Irma T. Hirschl Award
- National Institutes of Health Director's New Innovator Award [1DP2AI104556-01]
Ask authors/readers for more resources
Small RNAs undergo maturation events that precisely determine the length and structure required for their function. CRISPRs (clustered regularly interspaced short palindromic repeats) encode small RNAs (crRNAs) that together with CRISPR-associated (cas) genes constitute a sequence-specific prokaryotic immune system for anti-viral and anti-plasmid defense. crRNAs are subject to multiple processing events during their biogenesis, and little is known about the mechanism of the final maturation step. We show that in the Staphylococcus epidermidis type III CRISPR-Cas system, mature crRNAs are measured in a Cas10.Csm ribonucleoprotein complex to yield discrete lengths that differ by 6-nucleotide increments. We looked for mutants that impact this crRNA size pattern and found that an alanine substitution of a conserved aspartate residue of Csm3 eliminates the 6-nucleotide increments in the length of crRNAs. In vitro, recombinant Csm3 binds RNA molecules at multiple sites, producing gel-shift patterns that suggest that each protein binds 6 nucleotides of substrate. In vivo, changes in the levels of Csm3 modulate the crRNA size distribution without disrupting the 6-nucleotide periodicity. Our data support a model in which multiple Csm3 molecules within the Cas10.Csm complex bind the crRNA with a 6-nucleotide periodicity to function as a ruler that measures the extent of crRNA maturation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available