Molecular Biological Studies of the Mechanisms in Amphibian Spermatogenesis.

1.FSH在蝾螈睾丸组织培养中从次级精原细胞分化为初级精母细胞。食蟹猴：单独用卵泡刺激素(FSH)培养富含次级精原细胞的睾丸碎片，2周时半数以上的囊内出现初级精母细胞。这些结果表明，FSH是精原细胞向初级精母细胞分化所必需的，也是充分的。II.成熟精子的鞭毛长度是如何确定的？非洲爪蛙和非洲爪鼠圆形精子细胞鞭毛生长的比较：非洲爪鼠精子鞭毛长度是非洲爪鼠精子的13倍。爪蛙精子细胞的鞭毛生长速度和生长周期是非洲爪蛙的2~3倍。鞭毛伸长时期与微管蛋白合成时期基本一致。爪猴和非洲爪鼠微管蛋白合成速度和周期的差异似乎是…非洲爪哇精子细胞中精子特异性碱性核蛋白(SPS)的合成和初级精母细胞中SP4mRNA的表达：在圆形精子细胞的同步培养中，SP1、3-5的合成从第3天开始。Northern杂交结果表明，SP4和5mRNAs存在于初级精母细胞和圆形精母细胞中。这一结果表明，SP4和SP5基因在初级精母细胞阶段转录，但在圆形精子细胞阶段转录。IV.套膜(微管束)在中华绒螯蟹精细胞核伸长中的作用：微管在精子细胞核形成中的作用尚未确定。我们发现，细长精细胞的套筒结构对钙离子和低温的处理具有抵抗性。从低温稳定的睾丸微管中提取的1M氯化钠溶液在37℃时促进微管蛋白的聚合，在0℃时抑制解聚，并呈剂量依赖关系。这些结果表明，1M的氯化钠Sup含有促进微管蛋白聚合和抵抗微管蛋白解聚的微管相关蛋白(MAPs)。较少

I. Differentiation from secondary spermatogonia to primary spermatocytes by FSH in organ culture of testes fragments from the newt. Cynops pyrrhogaster : When testes fragments rich in secondary spermatogonia were cultured in the presence of follicle-stimulating hormone (FSH) alone, primary spermatocytes appeared in more than half of the cysts by the second week. These results indicate that FSH is indispensable and sufficient for the differentiation from spermatogonia to primary spermatocytes.II. How is the flagellar length of mature sperm determined ? Comparison of flagellar growth in round spermatids between Cynops and Xenopus : The flagellar length of Cynops sperm is 13 times longer than that of Xenopus sperm. The rate and period of flagellar growth in Cynops spermatids were 2 to 3-fold those in Xenopus. The period of flagellar elongation almost coincided with that of tubulin synthesis. The differences in the rate and period of tubulin synthesis between Cynops and Xenopus seems to be … More due to the difference in the stability of tubulin mRNAs between the two species.III. Synthesis of sperm-specific basic nuclear proteins (SPs) in spermatids and expression of SP4 mRNA in primary spermatocytes from Xenopus laevis : In synchronous culture of round spermatids, the synthesis of SP1, 3-5 began by day 3. CDNA clones for SP4 and 5 were isolated from a cDNA library from round spermatids. The Northern blots showed that SP4 and 5 mRNAs were present in primary spermatocytes as well as in round spermatids. This result shows that SP4 and 5 genes are transcribed in the primary spermatocyte stage but are translated at the round spermatid stage.IV. Role of manchette (microtubule bundles) in nuclear elongation in spermatids from Cynops pyrrhogaster : The role of microtubules in nuclear shaping of spermatids has yet to be determined. We found that manchette structure in newt elongate spermatids is resistant to the treatment of Ca^<2+> and low temperature. 1M NaCl Sup extracted from low temp-stable microtubules in testes promoted polymerization of tubulin at 37 C and resisted depolymerization at 0 C in a dose-dependent manner. These results indicate that 1M NaCl Sup contains MAPs (microtubule associated proteins) which promote tubulin polymerization and confer the resistance against tubulin depolymerization. Less