A Novel Gene Required for Sertoli-Spermatids Adhesion

描述（由申请人提供）：每年，在美国有超过100万例因意外怀孕而进行的堕胎。因此，意外怀孕对个人和社会都有重大的负面影响。避孕是减少意外怀孕的有效方法。进一步降低意外怀孕率的一种方法是开发安全有效的可逆男性避孕方法。以激素为基础的方法已被开发用于男性。然而，这些可能有明显的副作用，包括避孕和逆转所需的时间。理论上，一种特定的精子生成抑制剂可能是一种强有力的避孕方法，因为它应该相对迅速地起作用和逆转。因此，基础研究面临的挑战是提高我们对精子发生所需的基因产物和途径的理解，以便将其中的一些发现转化为男性避孕的新方法。为了实现这一目标，我们在小鼠中使用随机插入突变来鉴定哺乳动物精子发生所需的特定基因。纯合子共塑精子（sys）雄性小鼠是不育的，因为在精子延伸之前，精子与支持细胞的粘附存在缺陷。该突变涉及小鼠14号染色体上1.2 Mb的缺失，似乎只包含一个新基因。该基因编码一种富含脯氨酸的n端膜锚定结构蛋白。我们假设这个新基因的缺陷是导致雄性纯合子不育的原因，该基因在Sertoli细胞中起作用，介导精子与Sertoli的粘附，并且在可育的成年雄性小鼠中抑制该基因的功能可以阻断精子的发育。提出了五个具体目标来验证这一假设。首先，我们将产生具有新基因特定突变的雄性小鼠，并验证它们是不育的。其次，我们将利用生殖细胞移植来研究在睾丸内的生殖细胞或体细胞中是否需要新基因的功能。第三，我们将利用RNA原位杂交、免疫组织化学和生化方法分析该基因产物在睾丸中的表达模式和亚细胞分布。第四，我们将通过鉴定睾丸中与其相互作用的蛋白质来研究基因产物的功能。最后，我们将研究该基因在成年可育雄性小鼠中的失活是否会阻碍精子发生。这一基础研究的结果将为精子-黏附所需的新基因产物提供信息。他们还将对这种新基因产物的适用性进行评估，以作为开发新的男性避孕方法的潜在目标。

DESCRIPTION (provided by applicant): Each year, over 1 million abortions are performed in the US as a consequence of unintended pregnancy. Unintended pregnancies therefore have a significant negative impact on both the individual and society. Contraception is an effective method of reducing unintended pregnancies. One way to further reduce the rate of unintended pregnancies is to develop safe and effective methods for reversible male contraception. Hormone based approaches have been developed for use in men. However, these can have significant side effects including the length of time required for both contraception and its reversal. In theory, a specific inhibitor of spermiogenesis could be a powerful contraceptive method, as it should take effect, and be reversed, relatively quickly. Thus, a challenge for basic research is to improve our understanding of the gene products and pathways required for spermiogenesis so that some of these discoveries may be translated into novel approaches for male contraception. Towards this goal, we have used random insertional mutagenesis in mice to identify genes required specifically for mammalian spermatogenesis. Homozygous symplastic spermatids (sys) male mice are sterile due to a defect in spermatid-Sertoli cell adhesion just prior to spermatid elongation. The sys mutation involves a deletion of 1.2 Mb of mouse chromosome 14 that appears to contain only one, novel gene. This gene is predicted to encode a membrane-anchored structural protein with a proline rich N-terminus. We hypothesize that a defect in this novel gene is responsible for the sterility in sys homozygote males, that this gene functions in the Sertoli cell to mediate spermatid-Sertoli adhesion, and that inhibition of the genes function in fertile adult male mice could block spermatid development. Five specific aims are proposed to test this hypothesis. First, we shall generate male mice with a specific mutation of the novel gene and verify that they are sterile. Second, we shall use germ cell transplantation to investigate whether the function of the novel gene is required in germ cells or somatic cells within the testes. Third, we shall analyze the expression pattern and subcellular distribution of the gene product in testes using RNA in situ hybridization, immunohistochemistry and biochemical methods. Fourth, we shall investigate how the gene product functions by identifying proteins that interact with it in the testes. Finally, we shall investigate whether inactivation of this gene in adult fertile male mice can block spermiogenesis. The results of this basic research will provide information about a new gene product whose function is required for spermatid-Sertoli adhesion. They will also provide an assessment of the suitability of this novel gene product as a potential target for development of new methods of male contraception.