CRISPR RNA

CRISPR RNA or crRNA is a RNA transcript from the CRISPR locus.[1] CRISPR-Cas (clustered, regularly interspaced short palindromic repeats - CRISPR associated systems) is an adaptive immune system found in bacteria and archaea to protect against mobile genetic elements, like viruses, plasmids, and transposons.[2] The CRISPR locus contains a series of repeats interspaced with unique spacers. These unique spacers can be acquired from MGEs.[2]

Transcripts of the CRISPR Genetic Locus and Maturation of pre-crRNA.

Pre-crRNA is formed after the transcription of the CRISPR locus and before being processed by Cas proteins. Mature crRNA transcripts contain a partial conserved section of repeat and a sequence of spacer that is complementary to the target DNA.[3] crRNA forms an effector complex with a single nuclease or multiple Cas proteins called a Cascade (CRISPR-associated complex for antiviral defense).[3][1] Once the effector complex is formed a Cas nuclease or single effector protein will cause interference guided by the crRNA match.[4]

  1. ^ a b Gasiunas, Giedrius; Barrangou, Rodolphe; Horvath, Philippe; Siksnys, Virginijus (2012-09-25). "Cas9–crRNA ribonucleoprotein complex mediates specific DNA cleavage for adaptive immunity in bacteria". Proceedings of the National Academy of Sciences. 109 (39): E2579-86. doi:10.1073/pnas.1208507109. ISSN 0027-8424. PMC 3465414. PMID 22949671.
  2. ^ a b Faure, Guilhem; Shmakov, Sergey A.; Yan, Winston X.; Cheng, David R.; Scott, David A.; Peters, Joseph E.; Makarova, Kira S.; Koonin, Eugene V. (August 2019). "CRISPR–Cas in mobile genetic elements: counter-defence and beyond". Nature Reviews Microbiology. 17 (8): 513–525. doi:10.1038/s41579-019-0204-7. ISSN 1740-1534. PMC 11165670. PMID 31165781. S2CID 174809341.
  3. ^ a b Karvelis, Tautvydas; Gasiunas, Giedrius; Miksys, Algirdas; Barrangou, Rodolphe; Horvath, Philippe; Siksnys, Virginijus (2013-05-01). "crRNA and tracrRNA guide Cas9-mediated DNA interference in Streptococcus thermophilus". RNA Biology. 10 (5): 841–851. doi:10.4161/rna.24203. ISSN 1547-6286. PMC 3737341. PMID 23535272.
  4. ^ Jinek, Martin; Chylinski, Krzysztof; Fonfara, Ines; Hauer, Michael; Doudna, Jennifer A.; Charpentier, Emmanuelle (2012-08-17). "A programmable dual RNA-guided DNA endonuclease in adaptive bacterial immunity". Science. 337 (6096): 816–821. Bibcode:2012Sci...337..816J. doi:10.1126/science.1225829. ISSN 0036-8075. PMC 6286148. PMID 22745249.