CRISPR-Cas9 recognition of enzymatically synthesized base-modified nucleic acids

Hui Yang, Elena Eremeeva, Mikhail Abramov, Maarten Jacquemyn, Elisabetta Groaz, Dirk Daelemans, Piet Herdewijn

Nucleic Acids Research, gkac1147,

With the advent of CRISPR-Cas9 gene editing, we now have to hand a simple two-component system amendable to silencing and knock-in editing effectively any gene. Yet we must not forget that the implications of immunotoxicity along with the poor stability and specificity of canonical nucleic acids hold enormous challenges for in vivo applications, especially in gene therapy. Our study endorses the feasibility of the enzymatic approach to incorporate nucleobase modifications into the CRISPR-Cas9 system unveiling the tolerance of Cas9 to N1-methylpseudouridine (m1Ψ)- and emissive thienoguanosine (thG)-modified sgRNA as well as thus far uncharted structural requirements for ensuring proper PAM recognition.

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