NAT10-mediated mRNA N4-acetylation is essential for the translational regulation during oocyte meiotic maturation in mice.

The precise translational regulation of maternal messenger RNAs (mRNAs) drives mammalian oocyte maturation. However, the function and mechanism of posttranscriptional chemical modifications, especially the newly identified N4-acetylcytidine (ac4C) modification catalyzed by N-acetyltransferase 10 (NAT10), are unknown. In this study, we developed a low-input ac4C sequencing technology, ac4C LACE-seq, and mapped 8241 ac4C peaks at the whole-transcriptome level using 50 mouse oocytes at the germinal vesicle stage. Oocyte-specific Nat10 knockout wiped out ac4C signals in oocytes and caused severe defects in meiotic maturation and female infertility. Mechanically, Nat10 deletion led to a failure of ac4C deposition on mRNAs encoding key maternal factors, which regulate transcriptome stability and maternal-to-zygotic transition. Nat10-deleted oocytes showed decreased mRNA translation efficiency due to the direct inhibition of ac4C sites on specific transcripts during meiotic maturation. In summary, we developed a low-input, high-sensitivity mRNA ac4C profiling approach and highlighted the important physiological function of ac4C in the precise regulation of oocyte meiotic maturation by enhancing translation efficiency.