Vivian Nguyen Rose Hills
Engineering Novel Cas9 PAM Targeting Variants for Therapeutic Use
Over the past decade, CRISPR-Cas9 has emerged as an unparalleled tool for single-gene disease therapy. Yet, the vast majority of the genome is currently untargetable by Cas9 due to its strict requirement for a specific protospacer adjacent motif (PAM). While there have been attempts to engineer Cas9 with broader PAM recognition, these variants exhibit significantly lower on-target specificity and higher off-target activity compared to wild type Streptococcus pyogenes Cas9. To expand Cas9’s targetable genomic space without decreased on-target activity and increased off target editing, this research aims to engineer novel SpCas9 variants capable of specifically recognizing non-NGG PAMs through directed evolution in a yeast selection system. I will focus on engineering a SpCas9 variant that can specifically recognize the NAC PAM to treat retinitis pigmentosa, a dominant genetic disorder that causes blindness. Ultimately, this project will help expand and diversify the therapeutic potential of CRISPR-Cas9.