跨膜蛋白CMTM2在人睾丸和精子中的表达及定位

目的：通过研究跨膜蛋白CMTM2在睾丸和精子中的表达来探讨CMTM2蛋白在男性生殖系统中潜在的功能。方法：Western blot方法检测CMTM2在人睾丸及精子中的表达，免疫组织化学及组织免疫荧光方法检测CMTM2在人睾丸组织中的定位，TRITC-CMTM2及FITC-Hoechst免疫荧光双染法检测CMTM2在人精子顶体反应前后的定位。结果：CMTM2在人睾丸及精子中均有表达，在睾丸组织中CMTM2定位于各级生精细胞的细胞膜，睾丸组织冰冻切片免疫荧光检测的结果与免疫组织化学一致，进一步证实CMTM2存在于睾丸各级生精细胞的细胞膜，在精子中则定位于核后区附近。以TRITC-CMTM2及FITC-Hoechst免疫荧光双染法检测CMTM2在人精子顶体反应前后的定位，在顶体反应前后，CMTM2在人精子的定位及表达量未发生改变。结论：CMTM2在人睾丸和精子中均有表达，其表达定位具有细胞特异性和区域特异性，提示其可能在人睾丸精子发生和精卵融合过程中发挥作用，是男性不育研究的靶基因。CMTM2在男性生殖系统中的表达呈现细胞与生精区域的特异性，提示其高度参与生精功能，但目前针对CMTM2在男性生殖系统与精子生成过程中的作用仍未明确，今后可以采用体外受精 胚胎移植等技术进一步研究CMTM2的作用。

Expression and localization of transmembrane protein CMTM2 in human testis and sperm

Objective: To study the expression of transmembrane protein CMTM2 in the testis and sperm of adult males and to approach the potential function of the protein in the male reproductive system.Methods: The expression of CMTM2 in human testis and sperm was confirmed by Western blot.Immunohistochemical staining was used for detecting CMTM2 localization in the testis tissue, TRITC-CMTM2 and FITC-Hoechst double immunofluorescence staining was performed to examine the subcellular localization of CMTM2 in the human sperm before and after acrosome reaction, that is, immunofluorescent staining was used for detecting CMTM2 localization in both the testis and sperm before and after the acrosome reaction.Results: CMTM2 was presented in both human testis and sperm.In the testis, CMTM2 immunoreactive particles were observed mainly in the membrane of the different stages of spermatogenic cells.In the human sperm, its immunoreactivity was restrictively localized to the posterior head where sperm-egg fusion occurred, and the CMTM2 localization was not affected by sperm acrosome reaction.CMTM2 was widely expressed in seminiferous tubules of the human testis, mainly in the cell membranes of spermatogenic cells, which was consistent with the previous reports.The immunofluorescence performed on frozen human testis slides showed similar findings with immunohistochemistry, which gave weight to the localization of CMTM2 in the cell membranes of spermatogenic cells at different stages.TRITC-CMTM2 and FITC-Hoechst double immunofluorescence staining was performed to examine the subcellular localization of CMTM2 in the human sperm before and after acrosome reaction.CMTM2 was localized at the posterior head of sperm before and after acrosome reaction.The localization and expression of CMTM2 were not affected by sperm acrosome reaction.Conclusion: Expression of CMTM2 in the male reproductive system of the adult human exhibits cell-and region-specific patterns, which suggests that they may play an important role in spermatogenesis and sperm-egg fusion.The expression of CMTM2 in the male reproductive system of the adult human exhibits cell-and region-specific patterns, which suggests that they may play an important role in spermatogenesis and sperm-egg fusion.However, it still remains to be further elucidated about the definite role of CMTM2 in male reproductive system and the process of spermatogenesis.And in vitro fertilization experiments are needed to confirm the role of CMTM2 in fertilization in future.