EXPRESSION OF HEAT-SHOCK GENES IN MOUSE SPERMATOGENIC CELLS

环境胁迫后热休克蛋白（HSP）的合成 是一种高度保守的反应，显然可以保护细胞免受急性 不利条件的影响。 最丰富的蛋白质之一（P70） 生精细胞内的ATP含量与热休克蛋白70密切相关 亲和层析纯化，二维免疫印迹 蛋白质凝胶和肽图谱。 P70蛋白是在 精子发生的减数分裂阶段。 虽然几个成员的 hsp70基因家族已被测序，其mRNA表达 虽然这些基因的特征是，但对这些基因编码的蛋白质知之甚少。 我们研制了P70和hsp70的特异性抗血清， 这些蛋白质在雄性生殖细胞中的表达和作用。 抗血清 P70也被用于从小鼠精母细胞cDNA文库中选择克隆。 其中一个克隆与睾丸特异性的，发育性的 调节的3.0kb mRNA的表达不受热的影响。 序列 分析表明，该克隆与已报道的同源性较高 HSP70家族的基因 然而，生精细胞似乎 不产生热休克蛋白70的mRNA或蛋白。 这 提示P70基因表达与hsp70的抑制有关， 基因在生精细胞中的表达。 然而，精子发生的过程是 对温度升高和许多有毒物质异常敏感 P70可能在生殖细胞分化中起作用，而不是保护 对抗环境压力的影响。 虽然P70表达可能 有利于精子发生的过程，这个过程也可能 使雄性生殖细胞特别容易受到环境压力影响。 已经分离了P70基因的基因组克隆， 正在生产，以检查生精细胞特异性调节， 这个基因的表达。 一种构建体也正在准备中， P70基因在胚胎干细胞中的同源重组。 小鼠将被 在没有功能性P70基因的情况下产生，以测试P70蛋白的作用 在生精细胞功能和分化中的作用。

The synthesis of heat-shock proteins (hsp) following environmental stress is a highly conserved response and apparently protects cells against acute effects of detrimental conditions. One of the most abundant proteins (P70) in spermatogenic cells is related closely to hsp70, as shown by ATP affinity chromatography purification, immunoblots of two-dimensional protein gels, and peptide mapping. The P70 protein is synthesized during the meiotic phase of spermatogenesis. Although several members of the hsp70 gene family have been sequenced and their mRNA expression characterized, little is known about the proteins encoded by these genes. We developed antisera specific to P70 and hsp70 to investigate the expression and role of these proteins in male germ cells. The antiserum to P70 was also used to select clones from a mouse spermatocyte cDNA library. One of these clones hybridized to a testis-specific, developmentally regulated 3.0 kb mRNA whose expression was not affected by heat. Sequence analysis indicated that the clone has high homology to previously reported genes of the hsp70 family. However, it appears that spermatogenic cells do not produce hsp70 mRNA or protein in response to heat stress. This suggests that P70 gene expression is linked to suppression of the hsp70 gene in spermatogenic cells. However, the process of spermatogenesis is unusually sensitive to elevation of temperature and to many toxic agents and P70 may function in germ cell differentiation rather than to protect against the effects of environmental stress. Although P70 expression may be beneficial to the process of spermatogenesis, this process may also leave male germ cells particularly susceptible to environmental stress. Genomic clones have been isolated for the P70 gene and transgenic mice are being produced to examine the spermatogenic cell-specific regulation of expression of this gene. A construct is also being prepared to mutate the P70 gene by homologous recombination in embryonic stem cells. Mice will be produced without functional P70 genes to test the role of the P70 protein in spermatogenic cell function and differentiation.