REPRODUCTIVE BIOCHEMISTRY OF TESTES-SPECIFIC LDH-X

本研究的目的是阐明功能作用， 描述调节一个人的发育外观的因素。 与哺乳动物精子发生有关的独特蛋白质。 期间 在第一次减数分裂的前期， 表达的是阶段和/或细胞特异性的。 其中一个是 乳酸脱氢酶（LDH）同工酶可能发挥重要作用 在精子发生过程中的代谢作用。 LDH-C4已经很好 其特征在于其结构、生物化学和遗传学。 一个 对ldh-c基因调控的理解影响到以下问题： 从发育过程的角度来看， 不孕症以及生育控制。 小鼠和人ldh-c基因 在表达上显示出组织和时间特异性， 转录速率和mRNA稳定性的差异。 这些属性 将被用来识别对基因调控重要的DNA序列 以及DNA结合蛋白和转录因子参与 精子发生过程中的基因表达。 有三个具体目标： (1)为了鉴定调节ldh-c表达的DNA序列， 生精细胞 一种生殖细胞培养系统，其中该基因可以 已经建立，转基因小鼠将用于 确认睾丸特异性表达。 甲基化模式将是 在表达和非表达组织中进行比较;缺失分析将 用于建立调节所需的序列范围 转染试验中的活性;鉴定的精确调控序列 蛋白质-DNA相互作用的探针将被用来筛选睾丸 表达文库以克隆DNA结合因子;（2） 研究ldh-c mRNA稳定性和3'非翻译的作用， （3）干扰内源性LDH-C 通过与编码可选择的 新霉素抗性标记，从而消除LDH-C4蛋白 在这些靶向转基因小鼠中生产。 这将允许我们问 LDH-C4是否是精子发生和/或 精子 这些目标对于理解 精子发生过程中特定基因的表达。 他们还提供 对其他系统中类似发育过程的潜在洞察力， 例如造血、肿瘤发生和器官发生。

The goal of this research is to elucidate the functional role and describe the factors that regulate the developmental appearance of a unique protein associated with mammalian spermatogenesis. during the prophase of the first meiotic division a number of gene products are expressed that are stage and/or cell specific. One of these is an isozyme of lactate dehydrogenase (LDH) that may play an important metabolic role during spermatogenesis. LDH-C4 has been well characterized in terms of its structure, biochemistry and genetics. An understanding of ldh-c gene regulation impinges on questions concerning sperm production from the standpoint of developmental processes and infertility as well as fertility control. Mouse and human ldh-c genes show tissue and temporal specificity in expression but species differences in transcription rates and mRNA stability. These properties will be exploited to identify DNA sequences important for gene regulation as well as DNA binding proteins and transcription factors involved in gene expression during spermatogenesis. there are three specific aims: (1) to identify DNA sequences that regulate ldh-c expression in spermatogenic cells. A germ cell culture system in which this gene can be expressed, has been established and transgenic mice will be used to confirm testis-specific expression. Methylation patterns will be compared in expressing and non-expressing tissues; deletion analysis will be used to establish the extent of sequence necessary for regulatory activity in transfection assays; precise regulatory sequences identified by protein-DNA interactions will be used as probes to screen testis expression libraries in order to clone DNA binding factors; (2) to examine the role of ldh-c mRNA stability and of the 3' untranslated region in regulating translation; (3) to disrupt the endogenous ldh-c gene locus by homologous recombination with DNA encoding a selectable neomycin resistance marker and thereby eliminate LDH-C4 protein production in these targeted transgenic mice. This will permit us to ask whether LDH-C4 is absolutely required during spermatogenesis and/or in the spermatozoan. These goals are important to obtain an understanding of specific gene expression during spermatogenesis. They also provide potential insights into similar developmental processes in other systems, e.g. haematopoiesis, oncogenesis and organogenesis.