Department of Biochemistry and Molecular Biology, Medical School, Soochow University, Suzhou, China.
DNA Cell Biol. 2011 Jan;30(1):9-16. doi: 10.1089/dna.2010.1048. Epub 2010 Oct 27.
Testis is the one and only location of spermatogenesis and sexual hormone production. Spermatogenesis is a complicated physiological process regulated by many genes specifically and differentially expressed in the testis. In this study, Transmembrane Protein 225 (TMEM225), which is specifically expressed in rat testis, has been identified. TMEM225 was cloned from the testis cDNA library and was mapped to chromosome 8q22 by browsing the University of California Santa Cruz genomic database. It contains an open reading frame with a length of 696 bp, encoding a protein with four putative transmembrane helices. TMEM225 mRNA expression was evaluated by reverse transcription-polymerase chain reaction and in situ hybridization. In addition, the subcellular location of TMEM225 was evaluated. The results obtained highlighted age related specific expression of TMEM225 in testis, specifically during the adult period after age of 13 months. In situ hybridization analysis indicated that TMEM225 mRNA was mainly expressed in spermatocyte cells and round spermatids. Green fluorescence protein localization analysis showed that rat TMEM225 mainly surrounded the nuclear membrane, with a minority distribution in the cytoplasm, and the distribution of TMEM225 was affected by the deletion of N-terminal transmembrane domain. As the expression phase is not related to the first wave of spermatozoon development, our data presented here suggest that TMEM225 may play an important role in sperm degeneration but not in spermatogenesis.
睾丸是精子发生和性激素产生的唯一场所。精子发生是一个复杂的生理过程，受许多基因调控，这些基因在睾丸中特异性和差异表达。在这项研究中，鉴定了一种特异性表达于大鼠睾丸的跨膜蛋白 225（TMEM225）。TMEM225 从睾丸 cDNA 文库中克隆，并通过浏览加利福尼亚大学圣克鲁斯基因组数据库将其定位到 8q22 染色体上。它包含一个 696bp 的开放阅读框，编码一个具有四个假定跨膜螺旋的蛋白质。通过逆转录-聚合酶链反应和原位杂交评估 TMEM225 的 mRNA 表达。此外，还评估了 TMEM225 的亚细胞定位。结果表明，TMEM225 在睾丸中具有年龄相关的特异性表达，特别是在 13 个月后成年期。原位杂交分析表明，TMEM225 mRNA 主要在精母细胞和圆形精子中表达。绿色荧光蛋白定位分析表明，大鼠 TMEM225 主要环绕核膜，少数分布在细胞质中，TMEM225 的分布受 N 端跨膜结构域缺失的影响。由于表达阶段与第一波精子发生无关，我们这里的数据表明，TMEM225 可能在精子退化中发挥重要作用，但不在精子发生中发挥作用。
