A CRISPR/RfxCas13d-mediated strategy for efficient RNA knockdown in mouse embryonic development.

The growing variety of RNA classes, such as mRNAs, lncRNAs, and circRNAs, plays pivotal roles in both developmental processes and various pathophysiological conditions. Nonetheless, our comprehension of RNA functions in live organisms remains limited due to the absence of durable and effective strategies for directly influencing RNA levels. In this study, we combined the CRISPR-RfxCas13d system with sperm-like stem cell-mediated semi-cloning techniques, which enabled the suppressed expression of different RNA species. This approach was employed to interfere with the expression of three types of RNA molecules: Sfmbt2 mRNA, Fendrr lncRNA, and circMan1a2(2,3,4,5,6). The results confirmed the critical roles of these RNAs in embryonic development, as their loss led to observable phenotypes, including embryonic lethality, delayed embryonic development, and embryo resorption. In summary, our methodology offers a potent toolkit for silencing specific RNA targets in living organisms without introducing genetic alterations.