Progress on N⁴-acetylcytidine in animal reproductive development.

N⁴-acetylcytidine (ac⁴C) is an emerging RNA epigenetic modification that has attracted considerable attention in the field of epitranscriptomics in recent years. This modification is widely present in tRNA, rRNA, mRNA, and various non-coding RNAs. By precisely regulating RNA stability and translational efficiency, ac⁴C modulates the expression network of downstream genes, thereby playing a critical role in cellular function. In this review, we summarize recent advances in the distribution patterns, biological functions, and regulatory mechanisms of ac⁴C, highlight the associated writer enzymes, detection methodologies, and the involvement of ac⁴C in animal reproductive development. We aim to provide a solid theoretical foundation and valuable research insights for future investigations into the regulatory mechanisms of ac⁴C modification in animal and human reproduction.