Protospacer adjacent motif

A protospacer adjacent motif (PAM) is a 2–6-base pair DNA sequence immediately following the DNA sequence targeted by the Cas9 nuclease in the CRISPR bacterial adaptive immune system.[1] The PAM is a component of the invading virus or plasmid, but is not found in the bacterial host genome and hence is not a component of the bacterial CRISPR locus. Cas9 will not successfully bind to or cleave the target DNA sequence if it is not followed by the PAM sequence.[2][3][4][5] PAM is an essential targeting component which distinguishes bacterial self from non-self DNA, thereby preventing the CRISPR locus from being targeted and destroyed by the CRISPR-associated nuclease.[6]

  1. ^ Shah SA, Erdmann S, Mojica FJ, Garrett RA (2013). "Protospacer recognition motifs: mixed identities and functional diversity". RNA Biology. 10 (5): 891–899. doi:10.4161/rna.23764. PMC 3737346. PMID 23403393.
  2. ^ Mojica FJ, Díez-Villaseñor C, García-Martínez J, Almendros C (2009). "Short motif sequences determine the targets of the prokaryotic CRISPR defence system". Microbiology. 155 (Pt 3): 733–740. doi:10.1099/mic.0.023960-0. PMID 19246744.
  3. ^ Shah SA, Erdmann S, Mojica FJ, Garrett RA (2013). "Protospacer recognition motifs: mixed identities and functional diversity". RNA Biology. 10 (5): 891–899. doi:10.4161/rna.23764. PMC 3737346. PMID 23403393. Archived from the original on 2014-09-04.
  4. ^ Jinek M, Chylinski K, Fonfara I, Hauer M, Doudna JA, Charpentier E (2012). "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. PMC 6286148. PMID 22745249.
  5. ^ Sternberg SH, Redding S, Jinek M, Greene EC, Doudna JA (2014). "DNA interrogation by the CRISPR RNA-guided endonuclease Cas9". Nature. 507 (7490): 62–67. Bibcode:2014Natur.507...62S. doi:10.1038/nature13011. PMC 4106473. PMID 24476820.
  6. ^ Mali P, Esvelt KM, Church GM (2013). "Cas9 as a versatile tool for engineering biology". Nature Methods. 10 (10): 957–963. doi:10.1038/nmeth.2649. PMC 4051438. PMID 24076990.