Do we need Y chromosome for successful reproduction?

我们需要Y染色体才能成功繁殖吗？

• 批准号: 8399356
• 负责人: Monika A Ward
• 金额: $ 27.6万
• 依托单位: UNIVERSITY OF HAWAII AT MANOA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-25 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8399356
• 关键词: Abnormal Cell; Activities of Daily Living; Affect; Assisted Reproductive Technology; Bypass; Chromatin; Chromosomes; Chromosomes, Human, Y; Complement; DNA; DNA Packaging; Data; Defect; Development; Fathers; Fertility; Fertilization; Gene Delivery; Gene Transfer; Gene Transfer Techniques; Genes; Genetic; Germ; Germ Cells; Goals; Gonadal structure; Haploidy; Homologous Gene; Human; Infertility; Injection of therapeutic agent; Learning; Life; Link; Maintenance; Male Infertility; Mediating; Meiosis; Modeling; Mus; Oocytes; Personal Satisfaction; Play; Ploidies; Population; Process; Production; Regulation; Relative (related person); Reproduction; Role; Severities; Sex Chromosomes; Spermatids; Spermatogenesis; Testing; Testis; Transgenes; Transgenic Mice; Transgenic Organisms; Translating; Ultrasonography; Y Chromosome; Y chromosome deletion; arm; assisted reproduction; gene function; gene replacement; in vivo; male; men; mouse model; novel; offspring; overexpression; promoter; sex determination; sperm cell; sperm function; spermatogonial arrest; sry Genes; testis determining factor

DESCRIPTION (provided by applicant): Male infertility affects 5-10% of the population. A major factor associated with male infertility is Y chromosome deletions, yet our understanding of the requirement for specific genes on the Y chromosome and of their roles in sperm production/function is still poor. Y chromosome genes may provide essential spermatogenic functions or just potentiate the spermatogenic process. Our long-term goal is to define the function of Y chromosome encoded genes in mice in a context of assisted reproduction technologies (ART) as a way to model human Y- linked infertility cases. We have established that only two Y chromosome genes, testis determinant gene Sry and spermatogonial proliferation factor Eif2s3y are required for production of male gametes capable of participating in assisted fertilization. In Preliminary Data we show that males with a Y complement limited to Sry and Eif2s3y have spermatogenesis arrest and do not produce mature sperm. The precursor haploid germ cells (spermatids) are rare and often abnormal. Nevertheless, with round spermatid injection (ROSI) we succeeded in producing viable, healthy, and fertile progeny. This offers a promise to men with extensive Y gene loss and resulting azoospermia. Here, our specific goal is to define whether ART can be achieved even without this minimum Y gene contribution. We will test the hypothesis that the Y chromosome complement can be eliminated entirely while retaining production of functional male gametes. In Aim 1 we wil test if transgenic activation of Sox9, a downstream effector of Sry, will effectively replace Sry function and whether Sry-to-Sox9 replacement affects spermatogenesis and fertility, testing directly for the as yet unknown function of these genes in mature gonads. We will also establish if Eif2s3x, an X encoded homologue of Eif2s3y, can replace Eif2s3y function in spermatogonial proliferation. We will generate and characterize mice transgenic for Eif2s3x, and assess whether overexpression of Eif2s3x can rescue spermatogonial proliferation arrest in XOSry mice. In Aim 2, we will produce males without any Y genes but with overexpression of Eif2s3x and with transgenic activation of Sox9, as well as males with one Y gene retained and the other replaced. We will investigate how the presence of these genes affects spermatogenesis progression. We will also test if spermatogenesis in these males enables development of germ cells functional in ART, and whether such produced offspring are normal. In Aim 3, we will attempt to rescue spermatogonial arrest in testes of mature males with in vivo Eif2s3y gene transfer using novel 'active transgenesis' approach and ultrasound mediated gene delivery. Our studies will advance the understanding of (1) the roles that key players of sex determination (Sry and Sox9) play in mature gonads; (2) the roles of sex chromosome genes (Eif2s3y and Eif2s3x) in the initiation of spermatogenesis; and (3) the compatibility of extensive Y gene loss with successful ART. Our results should translate to enhance treatment of human infertility associated with Y chromosome deletions. ! PUBLIC HEALTH RELEVANCE: The project will test, in a mouse model, whether males lacking the entire Y chromosome can generate functional gametes and father healthy offspring with assisted reproduction, in spite of their obvious infertility in normal fertilization. This wil be of importance for infertile men with extensive Y chromosome deletions, which are a target group of human ART. The project will also advance the understanding of the roles of Y chromosome encoded genes in spermatogenesis.

描述（由申请人提供）：男性不育症影响 5-10% 的人口。与男性不育相关的一个主要因素是 Y 染色体缺失，但我们对 Y 染色体上特定基因的需求及其在精子产生/功能中的作用的了解仍然很少。 Y染色体基因可能提供必要的生精功能或只是增强生精过程。我们的长期目标是在辅助生殖技术 (ART) 的背景下定义小鼠 Y 染色体编码基因的功能，作为模拟人类 Y 连锁不孕病例的方法。我们已经确定，产生能够参与辅助受精的雄配子只需要两个Y染色体基因，即睾丸决定基因Sry和精原细胞增殖因子Eif2s3y。在初步数据中，我们表明，Y 补体仅限于 Sry 和 Eif2s3y 的男性精子发生停滞，并且不产生成熟精子。前体单倍体生殖细胞（精子细胞）很少见，而且通常是异常的。尽管如此，通过圆形精子细胞注射（ROSI），我们成功地产生了可存活、健康和可育的后代。这为 Y 基因大量缺失并导致无精症的男性带来了希望。在这里，我们的具体目标是确定即使没有这个最小 Y 基因贡献，是否也可以实现 ART。我们将检验这样的假设：Y 染色体互补体可以被完全消除，同时保留功能性雄性配子的产生。在目标 1 中，我们将测试 Sry 下游效应子 Sox9 的转基因激活是否将有效替代 Sry 功能，以及 Sry 到 Sox9 的替代是否会影响精子发生和生育能力，直接测试这些基因在成熟性腺中的未知功能。我们还将确定 Eif2s3x（Eif2s3y 的 X 编码同源物）是否可以替代 Eif2s3y 在精原细胞增殖中的功能。我们将生成并表征 Eif2s3x 转基因小鼠，并评估 Eif2s3x 的过度表达是否可以挽救 XOSry 小鼠的精原细胞增殖停滞。在目标 2 中，我们将产生没有任何 Y 基因但过度表达 Eif2s3x 并转基因激活 Sox9 的雄性，以及保留一个 Y 基因而替换另一个 Y 基因的雄性。我们将研究这些基因的存在如何影响精子发生进程。我们还将测试这些雄性的精子发生是否能够促进在 ART 中发挥功能的生殖细胞的发育，以及所产生的后代是否正常。在目标 3 中，我们将尝试使用新型“主动转基因”方法和超声介导的基因传递，通过体内 Eif2s3y 基因转移来挽救成熟男性睾丸中的精原细胞停滞。我们的研究将增进对以下方面的理解：(1) 性别决定的关键参与者（Sry 和 Sox9）在成熟性腺中所扮演的角色； (2)性染色体基因(Eif2s3y和Eif2s3x)在精子发生启动中的作用； (3) Y 基因广泛缺失与成功的 ART 相容。我们的结果应该能够转化为加强对与 Y 染色体缺失相关的人类不孕症的治疗。 ！ 公共健康相关性：该项目将在小鼠模型中测试缺乏完整 Y 染色体的雄性是否能够产生功能性配子并通过辅助生殖产生健康的后代，尽管它们在正常受精中明显不育。这对于 Y 染色体广泛缺失的不育男性非常重要，他们是人类 ART 的目标群体。该项目还将促进对 Y 染色体编码基因在精子发生中作用的理解。