The Role of Bcl-x in Murine Spermatogenesis

Bcl-x 在小鼠精子发生中的作用

• 批准号: 6732119
• 负责人: EDMUND B RUCKER
• 金额: $ 7.25万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-02 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6732119
• 关键词: Bax gene /protein; RNase protection assay; apoptosis; cell growth regulation; cell proliferation; fertility; gene expression; gene interaction; gene targeting; genetic regulation; genetically modified animals; genotype; immunocytochemistry; laboratory mouse; protooncogene; spermatogenesis; testis

DESCRIPTION (provided by applicant): Apoptosis, or programmed cell death, is a biochemical process that is mediated by a concert of cellular proteins including receptor "initiators" (e.g., TNFR tumor necrosis factor receptor superfamily), the mitochondrial-associating Bcl-2 family "mediators" (e.g., Bcl-2, Bax, Bcl-XL), and the protease "executioners" (e.g., caspases). Spermatogenesis can be blocked by the overexpression or deletion of these apoptosis-related genes, leading to male infertility or sterility. For example, ectopic expression of Bcl-2 and Bcl-x in transgenic mice inhibits apoptosis of spermatogonia and causes infertility. In addition, Bcl-x is expressed in the mouse and human testis within spermatogonia and spermatocytes. Due to the embryonic lethality associated with the bcl-x null mutation, it has not been possible to ascertain the role of Bcl-x in gamete development. Preliminary data support the hypothesis that Bcl-x is required to maintain the survival of spermatogonia and spermatocytes during murine spermatogenesis. To address this hypothesis the following specific aims are proposed. Specific Aim 1: Determine whether Bcl-x maintains the survival of spermatogonial cell populations in the mouse testes. To do this, we ablate the bcl-x gene in murine spermatocytes using the Cre-lox system. This approach will reveal the role of Bcl-x in spermatocyte survival in the mouse testis. Specific Aim 2: Determine whether Bcl-x and Bax are antagonists in the fate determination of the spermatogonial cell populations in the mouse testes. To do this, we will generate double mouse mutants that lack both the bcl-x and bax genes derived from Cre-lox (bcl-x) and conventional (bax) gene knockout strategies. Resultant mutants will demonstrate whether Bcl-x and Bax compete in determining the apoptotic fate of spermatocytes during murine spermatogenesis.

描述(申请人提供)：细胞凋亡，或程序性细胞死亡，是一种由一系列细胞蛋白介导的生化过程，包括受体“启动子”(例如，TNFR肿瘤坏死因子受体超家族)、线粒体相关的Bcl-2家族“介体”(例如，Bcl2、Bax、Bclxl)和蛋白水解酶“执行者”(例如，caspase)。这些凋亡相关基因的过度表达或缺失可阻止精子发生，导致男性不育或不育。例如，在转基因小鼠中异位表达Bcl2和Bclx可抑制精原细胞的凋亡，导致不育。此外，在小鼠和人的睾丸中，精原细胞和精母细胞中也有表达。由于与bclx零突变相关的胚胎致死性，目前还不可能确定bclx在配子发育中的作用。初步数据支持这样一种假设，即在小鼠精子发生过程中，精原细胞和精母细胞的存活需要Bcl-x来维持。为了解决这一假设，提出了以下具体目标。具体目的1：确定Bcl-x是否维持小鼠睾丸中精原细胞群体的存活。为了做到这一点，我们使用Cre-lox系统去除了小鼠精母细胞中的bclx基因。这一方法将揭示Bcl-x在小鼠睾丸精母细胞存活中的作用。特定目的2：确定Bclx和Bax是否是决定小鼠睾丸生精细胞群命运的拮抗剂。为了做到这一点，我们将产生双重小鼠突变体，它们既缺乏源于Cre-lox(Bclx)的bclx和bax基因，也缺乏传统的(Bax)基因敲除策略。由此产生的突变将证明在小鼠精子发生过程中，Bclx和Bax是否竞争决定精母细胞的凋亡命运。