SPAM 1 ALLELES, SPERM PHENOTYPE AND FUNCTION

描述：（从申请人的摘要扫描）的长期目标 我们的研究是为了确定a）PH-20或精子的表达是否 粘附分子1，SPAM 1（遗传命名法），揭示了一种机制， 透射比失真（TRD），B）如果保留Spam 1基因产物 以及控制其mRNA的调节机制 分布，以及c）SPAM 1的过表达如何影响精子功能。的 一项提案试图确定小鼠Spam 1基因产物，精子膜， 蛋白质（Spam 1），在连体精子细胞中共享， 杂合子或半合子在这方面是表型不同的。 抗原的该研究将利用罗伯逊易位（Rb（6.16）或 Rb}资源，其中杂合子显示TRD，并且其中Spam 1表达是 减少，以及过表达Spam 1转基因的半合子， 构建了Spam 1基因过表达对人肝癌细胞凋亡的影响 精子的能力也将通过利用 半合子以产生用于功能研究的转基因小鼠。因此 该提案涉及生殖生物学中的几个重要问题： 杂合子中精子的生化等效性， 睾丸生物学; mRNA的区室化及其调控 3' UTR中的共翻译组装和序列，以及 Spam 1在哺乳动物受精中的过表达。下列假设 将受到考验。1)有双峰分布的数量， Rb（6.16）/+小鼠精子细胞中Spam 1 mRNA和精子蛋白，与 在+/+和Rb/Rb小鼠中为单峰型，在Rb携带小鼠中RNA沉积较低 细胞后者可以通过转基因来拯救，以消除其减少的 Rb携带者的可移植性和TRD; Spam 1转基因的过表达将揭示Spam 1 mRNA和蛋白是否 在连体精子细胞中平均分配， 功能相同或不同的精子。纯合子将决定 过度表达对投资渗透率，药物结合率， 3）共翻译组装，序列介导 Spam 1的GPI-连锁和基因3' UTR中的序列介导其mRNA 导致TRD的区域化。这项工作有望影响目前 思考单倍体基因表达的关键原则， 阐明减数分裂驱动的机制，增加我们对 支持哺乳动物受精的分子机制， 人类生育力中精子-卵子相互作用改变的遗传基础。

DESCRIPTION: (Scanned from the applicant's abstract) The long-term objective of our studies are to determine a) if the expression of PH-20 or the Sperm Adhesion Molecule 1, SPAM1 (genetic nomenclature), reveals a mechanism for transmission ratio distortion (TRD), b) if the Spam1 gene product is retained in individual spermatids and the regulatory mechanism that controls its mRNA distribution, and c) how overexpression of SPAM1 affects sperm function. The proposal seeks to determine if the murine Spam1 gene product, a sperm membrane protein (Spam1), is shared among conjoined spermatids and whether the sperm of a heterozygote or hemizygote are phenotypically distinct with respect to this antigen. The study will make use of a Robertsonian translocation {Rb(6.16) or Rb} resource in which heterozygotes show a TRD and in which Spam1 expression is reduced, as well as hemizygotes for an overexpressed Spam1 transgene to be constructed. The effects of overexpression of Spam1 on the fertilizing competence of sperm will also be addressed by taking advantage of the hemizygotes to generate transgenic mice for functional studies. Thus the proposal addresses several important problems in reproductive biology: the biochemical equivalence of sperm in a heterozygote, a fundamental question in testicular biology; the compartmentalization of mRNA and its regulation by co-translational assembly and sequences in the 3' UTR, and the impact of overexpression of Spam1 on mammalian fertilization. The following hypotheses will thus be tested. 1) There is a bimodal distribution of the quantity of Spam1 mRNA in spermatids and protein in sperm from Rb(6.16)/+ mice, compared to a unimodal one in +/+ and Rb/Rb mice, with the lower RNA deposits in Rb-bearing cells. The latter can be rescued by transgenesis to eliminate their reduced fertilizing ability and TRD in Rb carriers; 2) Mice hemizygous for an overexpressed Spam1 transgene will reveal whether or not Spam1 mRNA and protein are equally shared among conjoined spermatids to produce biochemically and functionally equivalent or different sperm. Homozygotes will determine the effect of overexpression on the rates of investment penetration, zona binding, and fertilization, 3) Co-translational assembly, sequences mediating GPI-linkage of Spam 1, and sequences in the 3' UTR of the gene mediate its mRNA compartmentalization which leads to TRD. The work promises to impact current thinking about critical principles underlying haploid gene expression, elucidate a mechanism for meiotic drive, increase our understanding of the molecular mechanisms that underpin mammalian fertilization, and could identify a genetic basis for altered sperm-egg interactions involved in human fertility.