Molecular characterization of a germ-cell-specific antigen, TEX101, from mouse testis
Molecular characterization of a germ-cell-specific antigen, TEX101, from mouse testis
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DOI：
10.1017/s0967199406003753
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发表时间：
2006-08-01
期刊：
影响因子：
1.7
通讯作者：
Araki, Yoshihiko
中科院分区：
文献类型：
--
作者：
Jin, Hong;Yoshitake, Hiroshi;Araki, Yoshihiko
TEX 101是我们最近鉴定的一种糖蛋白，主要特征是作为一种独特的生殖细胞特异性标记蛋白，在小鼠性腺发育过程中表现出性二态性表达。基于从分子生物学以及免疫形态学研究中获得的数据，我们认为该分子可能在生殖细胞形成的过程中发挥作用。然而，由于其分子特征和生理功能还远未完全了解，许多问题仍不清楚。为了阐明TEX 101的分子基础，我们在此报告了使用小鼠睾丸Triton X-100提取物对该分子的进一步生物化学表征。使用内切糖水解酶从分子中删除N-连接寡糖（OS）的去糖基化研究表明，TEX 101是高度（约47%）N-糖基化的。TEX 101内所有潜在的N-糖基化位点均被糖基化，并且这些位点中的大多数被糖苷内切酶F2敏感性双触角复合物型OS单元占据。此外，TEX 101中极低的群体仅具有糖苷内切酶H敏感的杂交型OS单位。在使用磷脂酰肌醇特异性磷脂酶C对抗天然睾丸细胞或TEX 101转染子的研究中，酶处理引起细胞上TEX 101表达的主要减少，表明TEX 101至少部分表达为糖基磷脂酰肌醇锚定蛋白。总之，这些发现将有助于阐明TEX 101的分子性质，TEX 101是配子发生过程中出现在生殖细胞上的标记分子。
TEX101, a glycoprotein we recently identified, is primarily characterized as a unique germ-cell-specific marker protein that shows sexually dimorphic expression during mouse gonad development. Based on data obtained from molecular biological as well as immuno-morphological studies, we believe this molecule may play a role in the process underlying germ cell formation. However, many points remain unclear as the molecular characteristics and its physiological functions are far from being completely understood. To clarify the molecular basis of TEX101, we herein report a further biochemical characterization of the molecule using testicular Triton X-100 extracts from mice. Deglycosylation studies using endoglycohydrolases that delete N-linked oligosaccharides (OS) from the molecule show that TEX101 is highly (approximately 47%) N-glycosylated. All potential N-glycosylation sites within TEX101 are glycosylated and most of these sites are occupied by endoglycosidase F2-sensitive biantennary complex type OS units. In addition, an extremely low population among TEX101 possesses only endoglycosidase H-sensitive hybrid type OS units. In studies using phosphatidylinositol-specific phospholipase C against native testicular cells or TEX101 transfectant, the enzyme treatment caused major reduction of the TEX101 expression on the cell, suggesting that TEX101, at least in part, is expressed as a glycosylphosphatidylinositol-anchored protein. Taken together, these findings will help elucidate the molecular nature of TEX101, a marker molecule that appeared on germ cells during gametogenesis.