Characterization of MAGEG2 with testis-specific expression in mice

Abstract

Male germ cell development is a well-defined process occurring in numerous seminiferous tubules of the testis. Uncovering testicular novel genes related to intrinsic regulation of spermatogenesis is essential for the understanding of spermatogenesis. In the present study, we investigated mouse Mageg2, which belongs to a group of melanoma-associated antigens (MAGEs). Mageg2 is transcribed in the testis specifically, and its expression level is increased at the pachytene spermatocyte stage, indicating that Mageg2 is expressed predominantly in germ cells. We generated an antibody against mouse MAGEG2 for further characterization at the protein level. Immunoblot analysis suggested that MAGEG2 has specific testicular expression and the expression primarily occurred in pachytene spermatocytes. Proteomic analyses demonstrated that mouse MAGEG2 binded to testicular germ cell-specific serine/threonine-protein kinase 31 (STK31) and heat shock protein 9 (HSPA9). Direct binding with both interaction partners was confirmed by co-immunoprecipitation. We found that STK31 and HSPA9 bind MAGEG2 directly but not with each other. Interestingly, MAGEG2 reduced the kinase activity of STK31. Our study suggests that mouse MAGEG2 has at least two functions, including chaperone activity related to HSPA9 and regulation of pachytene spermatocyte-specific kinase, STK31. Altogether, our results provide the first information about MAGEG2 at the transcript and protein levels and suggest its potential molecular functions.

Comparative Analyses of Sperm DNA Methylomes Among Three Commercial Pig Breeds Reveal Vital Hypomethylated Regions Associated With Spermatogenesis and Embryonic Development

“…Consistently, a previous study reported that the loss of EXOSC10 in spermatogonia could lead to abnormal testicular development and a strongly decreased size (Jamin et al, 2017). HSPA9 has also shown low methylation levels at the promoter and is expressed at a high level in the testis, which plays an important role in prophase I of spermatogenesis by binding to testis-specific MAGEG2 (Melanoma Antigen Family G2) (Jeong et al, 2017). These results show that these conserved HMRs between the testis and sperm could be important candidate regions for the study of spermatogenesis and male infertility.…”

“…Several genes with hypomethylated promoter regions were highly expressed in the testis (Figure 4B). In particular, EXOSC10 (exosome component 10) and HSPA9 (heat shock protein family member 9) have been suggested to play important roles in male germ cell development (Jamin et al, 2017;Jeong et al, 2017).…”