LOCALIZATION OF SULFATED GLYCOPROTEIN-2 (CLUSTERIN) ON SPERMATOZOA AND IN THE REPRODUCTIVE-TRACT OF THE MALE-RAT
LOCALIZATION OF SULFATED GLYCOPROTEIN-2 (CLUSTERIN) ON SPERMATOZOA AND IN THE REPRODUCTIVE-TRACT OF THE MALE-RAT
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DOI：
10.1095/biolreprod45.1.195
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发表时间：
1991-07-01
影响因子：
3.6
通讯作者：
GRISWOLD, MD
中科院分区：
文献类型：
--
作者：
SYLVESTER, SR;MORALES, C;GRISWOLD, MD
硫酸糖蛋白-2 （SGP-2）是培养大鼠支持细胞和附睾细胞分泌的主要蛋白之一。由支持细胞分泌并在精小管液中发现的二硫连接二聚体蛋白由M(r) 47000和34000单体组成，而附睾蛋白则由M(r) 40000和29000单体组成。当这两种形式被化学或酶去糖基化时，它们产生了相似分子量的蛋白质。在培养培养基中未发现附睾细胞或液体对高分子量睾丸形态的改变。原位杂交法检测附睾上皮组织中SGP-2 mRNA的表达。Northern blot分析显示睾丸和附睾mrna的大小相似。这些发现表明，这两种形式的蛋白质是由于组织特异性翻译后修饰而发生的。从洗涤后的睾丸精子中提取的洗涤剂蛋白具有较高的分子量形式，而附睾精子具有较低的分子量形式。免疫组化证据显示睾丸形式在附睾初始段之前被移除，附睾形式在附睾头近端被应用。SGP-2在超微结构水平上免疫定位于精子膜，与外致密纤维蛋白和纤维鞘蛋白的免疫定位明显不同。
Sulfated glycoprotein-2 (SGP-2) is one of the major proteins secreted by rat Sertoli cells and epididymal cells in culture. The disulfide-linked dimeric protein secreted by Sertoli cells and found in seminiferous tubule fluid is composed of monomers of M(r) 47 000 and 34 000 whereas the epididymal protein exhibits monomers of M(r) 40 000 and 29 000. When both forms were chemically or enzymatically deglycosylated, they yielded proteins of similar molecular weight. No modification of the higher molecular weight testicular form by epididymal cells or fluids could be detected in incubation media. SGP-2 mRNA was localized in epididymal epithelium by in situ hybridization. Northern blot analysis indicated the testicular and epididymal mRNAs were of similar size. These findings suggest that the two forms of the protein occur because of tissue-specific post-translational modifications. The detergent-extracted protein from washed testicular spermatozoa is of the higher molecular weight form while epididymal sperm carry the lower molecular weight form. Immunohistochemical evidence suggests that the testicular form is removed prior to the initial segment of the epididymis and the epididymal form is applied in the proximal caput epididymidis. SGP-2 was immunolocalized to the sperm membrane at the ultrastructural level and was distinctly different from the immunolocalization of outer dense fiber proteins and fibrous sheath proteins.