GERM CELL-SPECIFIC MOLECULES OF SPERMATOZOA

正在研究哺乳动物精子发生过程中的基因表达 界定调节发展的内在机制和外在机制 雄配子的功能。正在研究的基因独特地表达在 生精细胞和/或在其发育的特定阶段。 已知蛋白质生殖细胞特异性亚型的编码包括 参与细胞-细胞间糖酵解酶和蛋白质的基因 互动。例如，分离的cDNA与RNA杂交 3-磷酸甘油醛脱氢酶(GAPD-S)和己糖激酶的表达 只存在于生精细胞中。GAPD-S基因在水稻减数分裂后表达 单倍体精子细胞，而己糖激酶基因的表达开始于 粗线期精母细胞的减数分裂。葡萄糖对分离的人有毒性 精子细胞，但精子是体外受精所必需的， 这表明糖酵解发生了独特的调节过程 生精细胞。此外，甘露糖6-磷酸(M6P)受体 在生精细胞上被鉴定，并被证明与M6P结合 支持细胞产生的配体。阳离子的多重转录本- 生殖细胞依赖的M6P受体包括未发现的1.2kb和1.4kb的mRNAs 在体细胞中。它们可能是由交替的多聚腺苷引起的。 信号，一个用于粗线期精母细胞，另一个用于粗线期精母细胞 精子细胞。已经有转基因小鼠被用来检测M6P的作用 精子特异性丝氨酸蛋白酶--顶体酶的靶向受体 顶体。靶向突变也被用来敲除顶体酶 检测生殖细胞发育和精子功能的基因 这种基因的突变。这些研究也可以作为影响的模型。 由环境因素引起的人类基因突变 通过父亲传给下一代。

Gene expression during spermatogenesis in mammals is being examined to define intrinsic and extrinsic mechanisms regulating development and function of male gametes. Genes being studied are expressed uniquely in spermatogenic cells and/or during specific stages of their development. The code for germ cell-specific isoforms of known proteins and include genes for glycolytic enzymes and proteins involved in cell-cell interaction. For example, cDNAs isolated hybridize with RNAs for glyceraldehyde 3-phosphate dehydrogenase (Gapd-s) and hexokinase expressed only in spermatogenic cells. The Gapd-s gene is expressed after meiosis in haploid spermatids, while expression of the hexokinase gene begins during meiosis in pachytene spermatocytes. Glucose is toxic to isolated spermatids but is required by spermatozoa for in vitro fertilization, indicating that unique regulatory processes occur for glycolysis in spermatogenic cells. In addition, mannose 6-phosphate (M6P) receptors have been identified on spermatogenic cells and shown to bind M6P-bearing ligands produced by Sertoli cells. Multiple transcripts for the cation- dependent M6P receptor in germ cells include 1.2 and 1.4 kb mRNAs not found in somatic cells. They probably arise from alternate polyadenylation signals, one being used in pachytene spermatocytes and the other in spermatids. Transgenic mice have been produced to examine the role of M6P receptors in targeting of acrosin, a sperm-specific serine protease, to the acrosome. Targeted mutations are also being used to knock out the acrosin gene to examine germ cell development and sperm function when there is a mutation in this gene. These studies also serve as models for the effects of gene mutations in humans caused by environmental agents that can be transmitted through the father to the next generation.