Correction of MECP2 Mutations with Engineered ScCas9 Base Editors
Joseph Jacobson, PhD
RSRT is funding various groups focused on fixing MECP2 mutations at the DNA level as well as the RNA level. In each of these scenarios we are pursuing “generic” options which would address 97% of all mutations, as well as “mutation-specific” options.
The mutation-specific programs currently have limitations as to the particular mutations that can be edited. For RNA we are limited to fixing mutations for which the editing enzyme is already known. To address this we are funding research to hopefully discover new editing enzymes to address additional mutations. Our DNA base editing programs use CRISPR-Cas systems. However, the range of mutations that can be fixed by CRISPR-Cas is currently limited by the requirement of a specific DNA sequence called the PAM (protospacer adjacent motif) that must reside at a specific distance from the mutation.
Using a big data computer science approach, the lab of Joe Jacobson has discovered a CRISPR-Cas enzyme that requires a minimalistic PAM sequence of just one base. This means that 50% of all DNA sequences can be targeted for correction. The next goal is the development of a CRISPR-Cas molecule that does not require a PAM sequence at all.
The objective of this pilot study is to engineer a CRISPR-Cas system to efficiently target C to T mutations within the MECP2 gene. C to T mutations account for the majority of MECP2 mutations including the top 8 most common mutations that account for almost 50% of all cases.