BASIS FOR MALE INFERTILITY--MOLECULAR MODELS

男性生育能力的一个重要方面是精子活跃的能力 穿过女性生殖道的某些区域，并穿透 鸡蛋投资。正常的鞭毛是这些功能所必需的。 然而，人们对控制精子鞭毛组装的基因知之甚少。 或者哺乳动物的能动性。私家侦探已经定位了一个基因，杂交性不育-6 (HST-6)，到等于或小于1厘米的区域 小鼠17号染色体的近三分之一。某些特定的组合 该基因座的等位基因导致严重的男性不育。实验室的小鼠 是来自另一只小鼠的HST-6(HST-6S/HST-6S)等位基因的纯合子 种，斯普雷特斯(S)，是不育的。他们的精子是静止的，因为 没有可辨认的轴丝。杂合子的实验室小鼠 HST-6S的一份拷贝和近三分之一的变异形式 被称为t单倍型(HST-6S/t)的17号染色体也是不育的。他们的 精子是能动的，但这些精子的鞭毛曲线异常，在 与携带两个T细胞的不育雄性精子的鞭毛相同 单倍型(t/t)。因此，很明显，HST-6具有两个遗传变异 一个等位基因影响轴丝分化，另一个等位基因 活动精子的鞭毛弯曲。 因为在哺乳动物中调节这些功能的基因还没有 分离的HST-6基因座为识别这类基因提供了一种新的方法。 因此，P.I.将首先克隆所有睾丸表达的基因 HST-6基因座(目标I)。确定哪些候选基因是 最有可能是HST-6，私家侦探将分析 大鼠睾丸mRNA和蛋白表达的基因序列和模式 根据我们目前的知识，每个候选基因的每个等位基因 HST-6突变表型(AIM II)。根据已知的功能， HST-6(轴丝组装和鞭毛曲率)，很可能是 HST-6蛋白特异性地定位于或非常接近轴丝。 附睾尾部精子。私家侦探将通过使用 用免疫细胞化学方法检测附睾尾精子的特异性 候选蛋白质的亚细胞定位 定位于发育中的精子细胞和/或成熟的尾部 睾丸精子(目标III)。这些实验将对 有助于我们理解精子鞭毛的遗传控制 集合和运动。此外，他们的成功将产生一个范例， 哺乳动物精子发育和功能的未来研究 在生化水平上的鞭毛。

An essential aspect of male fertility is the ability of sperm to actively move through certain regions of the female genital tract and penetrate the egg investments. Indispensable to these functions is a normal flagellum. Yet little is known about the genes which control sperm flagellar assembly or motility in mammals. The P.I. has mapped a locus, Hybrid Sterility-6 (Hst-6), to a region of equal to or less than 1 centimorgan (cM) in the proximal one third of mouse chromosome 17. The combination of certain alleles of this locus causes profound male sterility. Laboratory mice who are homozygous for an allele of Hst-6 (Hst-6S/Hst-6S) from another mouse species, Mus spretus (S), are sterile. Their sperm are immotile, due to the absence of a recognizable axoneme. Laboratory mice heterozygous for one copy of Hst-6S and a variant form of the proximal one third of chromosome 17 called a t haplotype (Hst-6S/t) are also sterile. Their sperm are motile, but the flagella of these sperm curve abnormally, in the same way as the flagella of sperm from sterile males carrying two t haplotypes (t/t). Thus, it is clear that Hst-6 has two genetically variant alleles, one affecting axonemal differentiation and the other, the curvature of the flagella of motile sperm. Because genes regulating these functions in mammals have not been isolated, the Hst-6 locus offers a novel approach to identify such genes. Therefore, the P.I. will first clone all testis-expressed genes that map to the Hst-6 locus (Aim I). To determine which of the candidate genes is most likely to be Hst-6, the P.I. will analyze the differences between the gene sequences and patterns of testicular mRNA and protein expression of each allele of each candidate gene with reference to our present knowledge of the Hst-6 mutant phenotypes (Aim II). Based upon the known functions of Hst-6 (axonemal assembly and flagellar curvature), it is likely that the Hst-6 protein specifically localizes in or very close to the axoneme of cauda epididymal sperm. The P.I. will test this hypothesis by using immunocytochemistry to examine cauda epididymal sperm for the specific subcellular location of candidate proteins that have already been localized to the tail region of developing spermatids and/or mature testicular sperm (Aim III). These experiments will contribute critical information to our understanding of the genetic control of sperm flagellar assembly and movement. Moreover, their success will produce a paradigm for the future study of the development and function of the mammalian sperm flagellum at the biochemical level.