Conclusion
Our results demonstrate the efficacy and versatility of the AAV9-mediated CRISPR-CasRx system as a flexible knockdown platform for studying gene function during spermatogenesis in vivo. This approach may advance the development of RNA-targeting therapies for conditions affecting reproductive health.
Methods
We used an adeno-associated virus serotype nine (AAV9)-mediated CRISPR-CasRx system to knock down the expression of exogenous and endogenous RNA transcripts in the testis. Virus particles were injected into the seminiferous tubules via the efferent duct. Using an autophagy inhibitor, 3-methyladenine (3-MA), we optimized the AAV9 transduction efficiency in germ cells in vivo.
Results
AAV9-mediated delivery of CRISPR-CasRx effectively and specifically induces RNA transcripts (both coding and noncoding) knockdown in the testis in vivo. In addition, we showed that the co-microinjection of AAV9 and 3-MA into the seminiferous tubules enabled long-term transgene expression in the testis. Finally, we found that a promoter of Sycp1 gene induced CRISPR-CasRx-mediated RNA transcript knockdown in a germ-cell-type-specific manner.