Decorating Chromatin for Precise Genome Editing Using CRISPR
Tech ID: 31814 / UC Case 2020-089-0
A novel fusion construct that fuses Cas9 to a truncated version of human PRDM9 with the purpose of improving precise genome editing via homologous direceted repair (HDR). PRDM9 is a protein that deposits histone marks H3K4me3 and H3K36me3 simultaneously during meiosis to mark recombination hot spots where crossover occurs and is resolved by homologous recombination. H3K36me3 has also been demonstrated to be required upstream of homologous recombination repair after double stranded breaks (DSBs) and during V(D)J recombination for adaptive immunity. Recent evidence suggests PRDM9 acts as a pioneer factor opening closed chromatin. The newly engineered PRDM9C-Cas9 fusion construct shows increased HDR and decreased non-homologous end joining mediated insertions and deletions (indels).
This newly engineered construct can be used to improve targeted insertions and substitutions mediated by CRISPR gene editing. Because of PRDM9’s function as a pioneer factor we expect this tool to allow increased HDR:indel ratios across different cell types and regardless of preexisting chromatin architecture. This is relevant to editing in mammalian cells, plants, yeast and any other organisms that organize their DNA into chromatin. We also expect this tool to lead to more precise genome editing in primary cell lines which would be relevant for medical applications.