Circular RNA regulates male spermatogenesis: a narrative review

Spermatogenesis was crucial for adult male animals to achieve reproductive function, and this complex physiological process required timely and moderate expression of related genes. A large number of epigenetic regulatory factors were involved, including cyclic RNA. Circular RNA had various characteristics such as rich expression, evolutionary conservation, cell or tissue specificity, and higher resistance to exonuclease or ribonuclease degradation. It can regulate the expression of parental genes and function as mRNA traps, miRNAs, or proteins in the corpus cavernous; it can also participate in the process of spermatogenesis through RNA-binding proteins, including the formation of reproductive stem cells, sperm formation, seminal plasma composition, and testicular tissue formation.