Testis-specific gene C7orf61 is involved in mouse sperm–egg fusion

The present study aimed to investigate the expression of chromosome 7 open reading frame 61 (C7orf61) in the testis and determine its role in spermatogenesis. Reverse transcription–quantitative polymerase chain reaction, Western blot and immunofluorescence were performed to evaluate the expression characteristics of C7orf61 in mice and humans. In vitro fertilization assay was used to determine the role of the C7ORF61 protein in sperm-egg fusion. The results demonstrated that C7orf61 was a testis-specific gene; the C7ofr61 mRNA expression level sharply increased in the fourth postnatal week and gradually increased until the adult stage. The C7ORF61 protein was located throughout the subacrosomal area and close to the nucleus in both mouse and human sperm. The incubation with the C7ORF61 antibody significantly decreased the fertilization rate of mouse eggs. The present findings suggested that the C7ORF61 protein might be involved in sperm–egg fusion, and could serve as a useful target for contraceptives. However, further research is still needed to know the detailed molecular mechanism of its role.