EXPRESSION OF HEAT SHOCK GENES IN MOUSE SPERMATOGENIC CELLS

许多蛋白质需要HSP70分子家族的帮助 多肽的折叠、运输、组装和拆解用的查帕酮 细胞中的复合体，并从变性状态中恢复 由热能和其他环境因素造成。热休克蛋白70蛋白在细胞周期调控中的作用 生精细胞特别令人感兴趣，因为这些细胞 维持在正常体温以下才能存活，并高度 易受环境因素破坏的。这可能是因为 通常由应激诱导的HSP70蛋白在 生精细胞。然而，另外两种独特的HSP70蛋白是 在这些细胞中大量表达，以响应发育提示。 HSP70-2蛋白是在减数分裂过程中合成的，我们发现 HSP70基因敲除小鼠生精细胞停滞于减数分裂中期和 经历细胞凋亡。Cyclin B1激活的CDC2激酶活性有一个关键 减数分裂中触发G2/M期转变的作用及其机制 HSP70-2蛋白似乎对细胞周期进程很重要 在精母细胞中。CDC2与HSP70-2在生殖细胞中的相关性 野生型小鼠并显示组蛋白H1激酶活性，但在HSP70-2基因中 基因敲除小鼠CDC2几乎没有可检测到的激酶活性。今年5月 这是由于CDC2/细胞周期蛋白B1复合体的形成缺陷所致。其他 研究正在使用转基因小鼠和体外方法来分析 该基因的启动子区域来识别顺式作用元件 它在发育过程中的表达。HSP70t蛋白是 HSP70家族的第二个成员，表达于生精细胞和 仅存在于减数分裂后阶段。基因打靶有 也被用来突变Hsc70t基因和杂合子小鼠 因为突变正在交配，以产生纯合的雄性后代。 通过与HSP70-2研究的类比，我们假设HSC70t 蛋白质是参与减数分裂后胚胎的独特蛋白质的一种查帕酮。 细胞发育。Hsc70t基因敲除的预测表型 是精子细胞形态发生、男性不育和生殖细胞的停滞 细胞凋亡。

Many proteins require assistance of the HSP70 family of molecular chaparones for folding,transport, assembly and disassembly of polypeptide complexes in the cell, and to recover from the denatured states caused by heat and other environmental agents. The roles of HSP70 proteins in spermatogenic cells is of special interest because these cells must be maintained below normal body temperature to survive and are highly susceptible to damage by environmental agents. This may be because the HSP70 proteins commonly induced by stress are weakly expressed in spermatogenic cells. However, two other unique HSP70 proteins are expressed abundantly in these cells in response to developmental cues. The HSP70-2 protein is synthesized during meiosis and we found that spermatogenic cells in HSP70 gene knockout mice arrest in mid-meiosis and undergo apoptosis. Cyclin B1-activated CDC2 kinase activity has a key role in triggering the G2/M-phase transition during meiosis and it appears that the HSP70-2 protein is important for cell-cycle progression in spermatocytes. CDC2 is associated with HSP70-2 in germ cells in wild-type mice and shows histone H1 kinase activity, but in HSP70-2 gene knockout mice the CDC2 has little detectable kinase activity. This may be due to a defect in formation of CDC2/cyclin B1 complexes. Other studies are using transgenic mice and in vitro methods to analyze the promoter region of this gene to identify cis-acting elements that direct its developmentally regulated expression. The HSP70t protein is the second member of the HSP70 family expressed in spermatogenic cells and is present exclusively during the postmeiotic phase. Gene targeting has also been used to mutate the Hsc70t gene and mice that are heterozygous for the mutation are being mated to produce homozygous male offspring. By analogy with the HSP70-2 studies, we hypothesize that the HSC70t protein is a chaparone for unique proteins involved in post-meiotic germ cell development. The predicted phenotype for the Hsc70t gene knockout is an arrest of spermatid morphogenesis, male infertility and germ cell apoptosis.