#PekingUniversity researchers discovered PmCas12m—a naturally nuclease-dead miniature Cas nuclease—and engineered #xCas12m (581 aa), enabling #single-AAV packaging of xCas12m-CRISPRoff for durable in vivo HBV epigenetic silencing in mice. 🧬🤖 #Epigenetics #CRISPRoff #GeneTherapy #HBV