RNA-Independent DNA Cleavage Activities of Cas9 and Cas12a

Autor: Ramya Sundaresan, Hari Priya Parameshwaran, S.D. Yogesha, Mark Walter Keilbarth, Rakhi Rajan
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Cell Reports, Vol 21, Iss 13, Pp 3728-3739 (2017)
Druh dokumentu: article
ISSN: 2211-1247
DOI: 10.1016/j.celrep.2017.11.100
Popis: CRISPR-Cas systems provide bacteria and archaea with sequence-specific protection against invading mobile genetic elements. In the presence of divalent metal ions, Cas9 and Cas12a (formerly Cpf1) proteins target and cleave DNA that is complementary to a cognate guide RNA. The recognition of a protospacer adjacent motif (PAM) sequence in the target DNA by Cas9 and Cas12a is essential for cleavage. This RNA-guided DNA targeting is widely used for gene-editing methods. Here, we show that Francisella tularensis novicida (Fno) Cas12a, FnoCas9, and Streptococcus pyogenes Cas9 (SpyCas9) cleave DNA without a guide RNA in the presence of Mn2+ ions. Substrate requirements for the RNA-independent activity vary. FnoCas9 preferentially nicks double-stranded plasmid, SpyCas9 degrades single-stranded plasmid, and FnoCas12a cleaves both substrates. These observations suggest that the identities and levels of intracellular metals, along with the Cas9/Cas12a ortholog employed, could have significant impacts in genome editing applications.
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