AUTHOR=Zhang Nan , Bewick Brittani , Xia Guangbin , Furling Denis , Ashizawa Tetsuo 

TITLE=A CRISPR-Cas13a Based Strategy That Tracks and Degrades Toxic RNA in Myotonic Dystrophy Type 1

JOURNAL=Frontiers in Genetics

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.594576

DOI=10.3389/fgene.2020.594576

ISSN=1664-8021

ABSTRACT=<p>Cas13a, an effector of type VI CRISPR-Cas systems, is an RNA guided RNase with multiplexing and therapeutic potential. This study employs the <italic>Leptotrichia shahii</italic> (<italic>Lsh</italic>) Cas13a and a repeat-based CRISPR RNA (crRNA) to track and eliminate toxic RNA aggregates in myotonic dystrophy type 1 (DM1) – a neuromuscular disease caused by CTG expansion in the <italic>DMPK</italic> gene. We demonstrate that <italic>Lsh</italic>Cas13a cleaves CUG repeat RNA in biochemical assays and reduces toxic RNA load in patient-derived myoblasts. As a result, <italic>Lsh</italic>Cas13a reverses the characteristic adult-to-embryonic missplicing events in several key genes that contribute to DM1 phenotype. The deactivated <italic>Lsh</italic>Cas13a can further be repurposed to track RNA-rich organelles within cells. Our data highlights the reprogrammability of <italic>Lsh</italic>Cas13a and the possible use of Cas13a to target expanded repeat sequences in microsatellite expansion diseases.</p>