<scp>NAT10</scp> regulates zygotic genome activation and the morula‐to‐blastocyst transition

As the first acetylated nucleoside to be discovered, N-acetyltransferase 10 (NAT10)-catalyzed RNA N4-acetylcytidine (ac⁴C) modification is involved in the occurrence of various diseases. However, the roles of RNA ac⁴C in preimplantation embryo development still need more detailed studies. Here, we analyzed the role of RNA ac⁴C in preimplanted embryonic development in mice through Nat10 siRNA microinjection and growing oocyte stage-specific Nat10 knockout (Zp3-Nat10^lox/lox). We found that NAT10 was indispensable for both the morula-to-blastocyst transition and zygotic genome activation (ZGA). Nat10 knockdown by Nat10 siRNA microinjection caused most embryos to arrest at the morula stage, and the expression levels of NANOG and CDX2 were significantly decreased. Moreover, the mRNA stability of Nanog was also significantly decreased in morulae after Nat10 knockdown. Zp3-Nat10^lox/lox female mice were completely sterile, and the embryos from Zp3-Nat10^lox/lox females were arrested at the 2-cell stage. Both the degradation of maternal mRNA and ZGA were deficient in 2-cell embryos from Zp3-Nat10^lox/lox females. In conclusion, our findings demonstrate that NAT10 is crucial for both ZGA and the morula-to-blastocyst transition processes during mouse preimplantation embryonic development.