Abstract
The CRISPR (clustered regularly interspaced short palindromic repeat) system is an RNA-guided immune system that protects prokaryotes from invading genetic elements. This system represents an inheritable and adaptable immune system that is mediated by multisubunit effector complexes. In the Type III-B system, the Cmr effector complex has been found to cleave ssRNA in vitro. However, in vivo, it has been implicated in transcription-dependent DNA targeting. We show here that the Cmr complex from Thermotoga maritimacan cleave an ssRNA target that is complementary to the CRISPR RNA. We also show that binding of a complementary ssRNA target activates an ssDNA-specific nuclease activity in the histidine–aspartate (HD) domain of the Cmr2 subunit of the complex. These data suggest a mechanism for transcription-coupled DNA targeting by the Cmr complex and provide a unifying mechanism for all Type III systems.
Original language | English (US) |
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Pages (from-to) | 460-470 |
Number of pages | 11 |
Journal | Genes and Development |
Volume | 30 |
Issue number | 4 |
DOIs | |
State | Published - Feb 15 2016 |
Keywords
- CMR
- CRISPR–Cas
- Nuclease
- RAMP
- RNA
ASJC Scopus subject areas
- Genetics
- Developmental Biology