大鼠精子细胞变态期核蛋白转换的研究

STUDIES ON RAT SPERMATID NUCLEAR PROTEIN TRANSITION

用细胞分离、免疫组织化学及同位素标记方法研究大鼠精子细胞变态期核蛋白转换（ＨＰＲＲ）所取得的结果。用速度沉降法（ｓｔａｐｕｔｍｅｔｈｏｄ）及超声法得到高纯度的睾丸圆形、长形精子细胞核及附睾精子核，提取其总碱性核蛋白（ＴＮＢＰ），电泳分析，发现睾丸圆形精子细胞核内为组蛋白；长形精子细胞核内主要为精核蛋白、少量过渡形蛋白（ＴＰｓ）及组蛋白；附睾精子核中主要为精核蛋白。免疫组织化学研究表明，只有长形精子细胞核内检测到精核蛋白，而圆形精子细胞、精母细胞及精原细胞核均为免疫组织化学阴性反应。用１４Ｃ－精氨酸注入大鼠睾丸后，分离睾丸圆形及长形精子细胞核，提取碱性核蛋白电泳后，测定各蛋白条带的放射量。在长形精子细胞检测到大量放射性精核蛋白存在，表明精核蛋白的生物合成及积聚是在此细胞阶段。上述研究结果表明，在大鼠精子形成中，其核蛋白经历了由组蛋白到精核蛋白的转换过程，精核蛋白是成熟精子的主要核蛋白。本文还对ＨＰＲＲ是精子发生中的薄弱环节和借此进行生育调控的可能性予以讨论。

uring spermiogenesis the somatic histones are stepwisely replaced by the transition proteins and protamines in spermatid nuclei, this process is termed histone to protamine replacement reaction (HPRR).Concomitantly with HPRR, the morphology of spermatid nuclei changed from round to elongating, and become highly condensed. In this report the HPRR was studied using cell separation, immunohistochemistry and isotope labelling techniques. Highly purified rat testis round spermatid(Rs), elongating spermatid(Es) nuclei and epididymal sperm nuclei were obtained by staput and sonication methods. Electrophoresis of total nuclear basic proteins (TNBP) from these nuclei revealed that the Rs possess the somatic histones. Basic proteins of Es consists of protamine and less histones as well as transition proteins. In epididymal sperm, the main basic proteins is protamine. Immunohistochemical studies of protamine indicate that the Es presents strongly stained nuclei, no staining is shown in the Rs as well as in other cell types. Testes are labelled by intratesticular injection of 14C arginine, the nuclei of Rs and Es were isolated, the TNBP were extracted and used for electrophoretic separation. Analysis of labelling paterns for TNBP from Rs and Es revealed that protamine is synthesized and accumulated in Es.These results demonstrate that dramatic transition occurrs in the nuclear proteins during spermiogenesis in rat, somatic histones are stepwisely replaced by transition proteins and protamine. Protamine is the main nuclear protein in mature spermatozoa. Concerning the HPRR is the weak link during spermatogenesis, the possibility for fertility control by HPRR is discussed.