N4-acetylcytidine (ac4C), an emerging posttranscriptional RNA modification, plays a pivotal role in epigenetic regulation. Ac4C is detected not only in tRNA, rRNA, and mRNA, but also in miRNA, lncRNA, viral RNA, and even DNA. Functionally, ac4C stabilizes mRNA, enhances protein translation fidelity, and impacts various biological processes and diseases such as cancer, inflammation, immune regulation, neural diseases, osteogenic differentiation, cardiovascular diseases, viral infections, and replication. Current research primarily focuses on ac4C's roles in cancer progression and immunity, with emerging findings in gynecological diseases and reproduction. However, a comprehensive understanding of ac4C's implications in reproductive health is lacking. This review provides a historical perspective on ac4C's discovery and detection methods, elucidates its functions in reproductive development and gynecological disorders, and offers insights for further research in reproductive health. This review aims to pave the way for innovative therapeutic approaches and precise diagnostic tools tailored to this field.
Humans ; Reproductive Health ; Cytidine/genetics* ; Animals ; Female ; RNA Processing, Post-Transcriptional ; Epigenesis, Genetic ; RNA/genetics*

Originating but free from chromosomal DNA, extrachromosomal circular DNAs (eccDNAs) are organized in circular form and have long been found in unicellular and multicellular eukaryotes. Their biogenesis and function are poorly understood as they are characterized by sequence homology with linear DNA, for which few detection methods are available. Recent advances in high-throughput sequencing technologies have revealed that eccDNAs play crucial roles in tumor formation, evolution, and drug resistance as well as aging, genomic diversity, and other biological processes, bringing it back to the research hotspot. Several mechanisms of eccDNA formation have been proposed, including the breakage-fusion-bridge (BFB) and translocation-deletion-amplification models. Gynecologic tumors and disorders of embryonic and fetal development are major threats to human reproductive health. The roles of eccDNAs in these pathological processes have been partially elucidated since the first discovery of eccDNA in pig sperm and the double minutes in ovarian cancer ascites. The present review summarized the research history, biogenesis, and currently available detection and analytical methods for eccDNAs and clarified their functions in gynecologic tumors and reproduction. We also proposed the application of eccDNAs as drug targets and liquid biopsy markers for prenatal diagnosis and the early detection, prognosis, and treatment of gynecologic tumors. This review lays theoretical foundations for future investigations into the complex regulatory networks of eccDNAs in vital physiological and pathological processes.
Male ; Female ; Animals ; Humans ; Swine ; DNA, Circular/genetics* ; Genital Neoplasms, Female ; Semen ; DNA ; Reproduction