SPAM 1 ALLELES, SPERM PHENOTYPE AND FUNCTION

描述：(摘自申请者摘要)长期目标 我们的研究是为了确定a)PH-20或精子的表达 黏附分子1，SPAM1(遗传命名)，揭示了一种 传输比失真(TRD)，b)如果Spam1基因产物被保留 在单个精子细胞中的表达及其控制其mRNA的调控机制 以及c)SPAM1的过表达如何影响精子功能。这个 一项旨在确定小鼠Spam1基因产物精子膜 蛋白质(Spam1)，在连接的精子细胞之间共享，而精子是否 杂合子或半合子在这方面是不同的表型。 抗原。这项研究将利用罗伯逊易位(Rb(6.16)或 Rb}杂合子显示TRD且Spam1表达为 减少，以及过表达Spam1转基因的半合子 建造的。Spam1基因过表达对受精的影响 精子的能力也将通过利用 半合子产生转基因小鼠用于功能研究。因此， 该提案解决了生殖生物学中的几个重要问题： 杂合子中精子的生物化学等价性 睾丸生物学；信使核糖核酸的区划及其调控 3‘非编码区中的共翻译组装和序列及其影响 Spam1基因在哺乳动物受精过程中的过表达以下假设 将会因此受到考验。1)有一个双峰分布的数量 Rb(6.16)/+小鼠精子细胞Spam1 mRNA和精子蛋白质的比较 在+/+和Rb/Rb小鼠中为单峰型，携带Rb的小鼠中RNA沉积较少 细胞。后者可以通过转基因来拯救，以消除它们减少的 Rb携带者的受精能力和TRD；2)小鼠半合子 过表达的Spam1转基因将揭示Spam1的mRNA和蛋白是否 在连接的精子细胞中平均分配，以生物化学和 功能相同或不同的精子。纯合子将决定 过度表达对包被渗透率、小带结合、 和受精，3)共翻译组装，序列介导 Spam 1的GPI连锁，以及该基因3‘端非编码区的序列介导其mRNA 导致TRD的分隔化。这项工作有望对当前的 思考单倍体基因表达的关键原则， 阐明减数分裂驱动机制，加深对减数分裂的认识 支持哺乳动物受精的分子机制，并可以识别 与人类生育有关的精子-卵子相互作用改变的遗传学基础。

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.