EXPRESSION OF HEAT SHOCK GENES IN MOUSE SPERMATOGENIC CELLS

热休克基因在小鼠生精细胞中的表达

• 批准号: 2574444
• 负责人: E M EDDY
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2574444
• 关键词: cell cycle proteins; developmental genetics; gene induction /repression; histones; laboratory mouse; male; meiosis; protein kinase; spermatogenesis; stress proteins

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.

许多蛋白质需要HSP 70家族分子的辅助。 用于多肽折叠、运输、组装和分解的伴侣蛋白 复合物在细胞中，并恢复从变性状态造成的 热和其他环境因素。 热休克蛋白70在肝硬化中的作用 生精细胞是特别感兴趣的，因为这些细胞必须是 维持在低于正常体温的温度下生存， 易受环境因素的损害。 这可能是因为 HSP 70蛋白通常由应激诱导表达，但在正常小鼠中表达较弱。 生精细胞 然而，另外两种独特的HSP 70蛋白是 在这些细胞中大量表达以响应发育线索。 HSP 70 -2蛋白在减数分裂期间合成，我们发现， HSP 70基因敲除小鼠的生精细胞在减数分裂中期停滞并 经历凋亡。 细胞周期蛋白B1激活的CDC 2激酶活性是一个关键 在减数分裂过程中触发G2/M期转换的作用， HSP 70 -2蛋白对细胞周期的进程有重要作用 在精母细胞中。 CDC 2与生殖细胞中的HSP 70 -2相关， 野生型小鼠，并显示组蛋白H1激酶活性，但在HSP 70 -2基因 在敲除小鼠中，CDC 2几乎没有可检测的激酶活性。 这可能 可能是由于CDC 2/细胞周期蛋白B1复合物形成缺陷。 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，以确定顺式作用元件， 其发育调控的表达。 HSP 70 t蛋白是一种 在生精细胞中表达的HSP 70家族的第二个成员， 只存在于减数分裂后期。 基因靶向具有 也被用于突变Hsc 70 t基因和杂合子小鼠， 进行交配以产生纯合子雄性后代。 通过与HSP 70 -2研究的类比，我们假设HSC 70 - 2表达水平与HSP 70 - 2表达水平无关。 蛋白是参与减数分裂后胚芽的独特蛋白的伴侣 细胞发育Hsc 70 t基因敲除的预测表型 抑制精子细胞形态发生、男性不育和生殖细胞 凋亡