What are the effects of chromatin configuration on HDR efficiency?
What are the effects of chromatin configuration on HDR efficiency?
It has been demonstrated that nucleosomes inhibit target cleavage by SpCas9 in vivo, suggesting that Cas9 activity is influenced by chromatin structure in addition to the inherent activity of a given sgRNA (Yarrington et al. 2018). Although DNA sequence is a significant determinant of site-specific indel profiles, it has been shown that packaging of DNA into chromatin may influence editing efficiency and the relative frequency of indels at a given locus (Chakrabarti et al. 2018). On the other hand, using imprinted genes as a test case, outcomes of gene editing events (i.e., the balance between HDR vs. NHEJ) were shown to be independent of chromatin state (Kallimasioti-Pazi et al. 2018).
References
Chakrabarti, A. M. et al. Target-Specific Precision of CRISPR-Mediated Genome Editing. Mol. Cell 73, 1–15 (2018).
Kallimasioti-Pazi, E. M. et al. Heterochromatin delays CRISPR-Cas9 mutagenesis but does not influence the outcome of mutagenic DNA repair. PLOS Biol. 16, e2005595 (2018).
Yarrington, R. M., Verma, S., Schwartz, S., Trautman, J. K. & Carroll, D. Nucleosomes inhibit target cleavage by CRISPR-Cas9 in vivo. Proc. Natl. Acad. Sci. 115, 9351–9358 (2018).