N-acetyltransferase 10-mediated mRNA N4-acetylation is Essential for the Translational Regulation During Oocyte Meiotic Maturation in Mice

Mammalian oocyte maturation is driven by the strict translational regulation of maternal mRNAs stored in the cytoplasm. However, the function and mechanism of post-transcriptional 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. We profiled the mRNA landscapes of NAT10-interactions and ac4C modifications. The NAT10-interacted and ac4C-modified transcripts are associated with high translation efficiency in oocytes. Oocyte-specific Nat10 knockout wiped out ac4C signals in oocytes and caused severe defects in meiotic maturation and female infertility. ac4C LACE-seq results indicated that Nat10 deletion led to a failure of ac4C deposition on mRNAs encoding key maternal factors, such as MSY2, ZAR1, BTG4, and cyclin B1, which regulate transcriptome stability and maternal-to-zygotic transition. Nat10-deleted oocytes showed decreased mRNA translation efficiency during meiotic maturation, partially due to the direct inhibition of ac4C sites on specific transcripts. 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.