The Basis for Male Infertility: Molecular Models

男性不育的基础：分子模型

• 批准号: 7198234
• 负责人: STEPHEN H PILDER
• 金额: $ 37.5万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-15 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7198234
• 关键词: Acids; Adaptor Signaling Protein; Alleles; Amino Acids; Animals; Automobile Driving; Calcium; Candidate Disease Gene; Cell Fractionation; Cell Line; Chronic; Cilia; Complex; Condition; Cyclic AMP; Decompression Sickness; Development; Diagnosis; Drops; Dynein ATPase; Dyskinetic syndrome; Elements; Epididymis; Event; Exons; Fertilization; Fertilization in Vitro; Flagella; Frequencies; Functional disorder; Genes; Goals; Haplotypes; Immunofluorescence Immunologic; Individual; Infertility; Knock-out; Link; Localized; Location; Male Infertility; Male Sterility; Mammals; Mass Spectrum Analysis; Microscopic; Molecular; Molecular Genetics; Molecular Target; Movement; Mutation; N-terminal; Pathway interactions; Phenotype; Process; Protein Isoforms; Protein phosphatase; Proteins; Proteome; Proteomics; Research Personnel; Role; Second Messenger Systems; Signal Transduction; Site; Sperm Motility; Sperm Tail; Stem cells; Sterility; Techniques; Testing; Testis; Time; To specify; Transgenes; Transmission Electron Microscopy; Variant; base; cell motility; comparative; human male; improved; light microscopy; mRNA Differential Displays; male; molecular modeling; mutant; novel therapeutics; protein expression; protein protein interaction; second messenger; sperm cell; therapeutic target

DESCRIPTION (provided by applicant): For mammalian sperm to fertilize, they must gain the ability to move progressively, and then switch to a form of vigorous, non-progressive movement, or hyperactivation, as they near the site of fertilization. Our long-term goal is to understand the molecular basis for the different flagellar waveforms that typify these two types of motility. The driving premise of this proposal is that the mutant activity of the protein products of three tightly-linked t complex genes in sperm from t haplotype (t) homozygous males leads to expression of the abnormal flagellar waveform phenotype, "curlicue". In this phenotype, sperm briefly hyperactivate immediately upon release from the epididymides into a medium that supports fertilization, then suffer a sharp drop in curvilinear velocity accompanied by the chronic negative bending of the entire flagellum. As a result, t/t males are sterile. The three candidate proteins are: DNAHC8, a principal piece-restricted, axonemal dynein heavy chain with a unique N-terminus; TCTEX5, an inhibitory subunit of the sperm-restricted protein phosphatase, PP1gamma2, localizing primarily to the flagellar midpiece; and TSGA2, a testis/sperm-limited protein whose two major isoforms are differentially distributed in the cytoskeletal elements of both the principal piece and midpiece, and which may function as calcium-sensitive adaptor proteins. Thus, the t alleles of these three genes appear to specify defective components of pathways controlling flagellar waveform dynamics in mammalian sperm. We therefore propose three specific aims in which we will employ molecular/genetic, microscopic, and proteomic approaches to verify the efficacy and determine the role of each candidate gene product in the elaboration of "curlicue", based on comparative expression, localization, and protein-protein interaction studies of wild-type and t haplotype isoforms. These studies will improve our understanding of the complex molecular mechanisms that underlie abnormal movement of the mammalian sperm flagellum and other cilia in the body. In so doing, they will impact positively on our ability to identify novel therapeutic targets for diagnosing and treating human male infertility as well as other pathological conditions related to ciliary dysfunction.

描述（由申请人提供）：哺乳动物精子要受精，它们必须获得渐进式运动的能力，然后在接近受精部位时转换为一种有力的、非渐进式运动或过度激活的形式。我们的长期目标是了解代表这两种运动类型的鞭毛波形的分子基础。该建议的驱动前提是，t单倍型(t)纯合雄性精子中三个紧密相连的t复合体基因的蛋白产物的突变活性导致异常鞭毛波形表型“curlicue”的表达。在这种表型中，精子从附睾释放到支持受精的培养基中后，立即短暂地过度激活，然后经历曲线速度的急剧下降，伴随着整个鞭毛的慢性负弯曲。因此，雌雄同体的雄性是不育的。这三种候选蛋白是：DNAHC8，一种主要的轴突动力蛋白重链，具有独特的n端；TCTEX5是精子限制性蛋白磷酸酶PP1gamma2的抑制亚基，主要定位于鞭毛中部；TSGA2是一种睾丸/精子限制蛋白，其两个主要亚型在主片段和中间片段的细胞骨架元件中分布不同，可能具有钙敏感适配蛋白的功能。因此，这三个基因的t等位基因似乎指定了哺乳动物精子中控制鞭毛波形动态的途径的缺陷成分。因此，我们提出了三个具体目标，我们将采用分子/遗传学，显微镜和蛋白质组学方法来验证功效，并确定每个候选基因产物在“curlicue”的阐述中的作用，基于野生型和t单倍型同种型的比较表达，定位和蛋白质-蛋白质相互作用研究。这些研究将提高我们对哺乳动物精子、鞭毛和其他纤毛异常运动的复杂分子机制的理解。在这样做的过程中，它们将对我们识别诊断和治疗人类男性不育以及与纤毛功能障碍相关的其他病理状况的新治疗靶点的能力产生积极影响。