Regulation of chromatin remodeling during spermiogenesis

精子发生过程中染色质重塑的调节

• 批准号: 8815702
• 负责人: PRABHAKARA P REDDI
• 金额: $ 7.86万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8815702
• 关键词: Accounting; Acrosome; Adult; Affect; Applications Grants; Archives; Assisted Reproductive Technology; Binding; Biological Models; Birth; Breeding; Bypass; CCCTC-binding factor; Cell Nucleus; Cells; ChIP-seq; Chromatin; Complex; Conceptions; Congenital Abnormality; Couples; DNA-Binding Proteins; Defect; Developed Countries; Development; Disease; Embryonic Development; Epigenetic Process; European; Event; Feasibility Studies; Fertility; Fertilization; Fetal Growth Retardation; Flagella; Genes; Genetic; Genetic Transcription; Genome; Germ Cells; Germ Lines; Histones; Human; Immunohistochemistry; Infertility; Injection of therapeutic agent; Intercistronic Region; Knock-out; Knockout Mice; Lead; Life; Male Infertility; Malignant Childhood Neoplasm; Methods; Modeling; Molecular; Mus; Mutant Strains Mice; Natural Selections; Nuclear; Nuclear Proteins; Phase; Physical condensation; Physical shape; Pilot Projects; Play; Preparation; Process; Protamines; Proteins; Regulation; Reproductive Health; Risk; Role; Sperm Maturation; Spermatids; Spermatogenesis; Spermiogenesis; Spontaneous abortion; Staging; Technology; Testing; Testis; Time; Treatment Factor; United States; Ursidae Family; Validation; Work; Zinc Fingers; age group; base; chromatin remodeling; egg; embryonic stem cell; gene repression; genome-wide; imprint; improved; insight; knockout gene; male; mouse model; novel; promoter; public health relevance; reproductive; research study; screening; sperm cell; technology development; transcription factor

 DESCRIPTION (provided by applicant): The differentiation of round spermatids into spermatozoa, known as spermiogenesis, is a complex process involving the formation of the acrosome, the flagellum, and condensation of the nucleus. In preparation for condensation, the spermatid nucleus undergoes dramatic chromatin remodeling including genome-wide cessation of transcription, dismantling of the nucleosomal organization, and histone to protamine transition. This process is unique to the male germ line. Mouse models have shown that defects in nuclear condensation lead to male infertility; however, the mechanisms regulating this complex genome-wide process are not well understood. Our working hypothesis is that the genome organizer protein CTCF coordinates the chromatin remodeling events accompanying spermatid differentiation. The evolutionarily conserved eleven zinc finger protein CCCTC-binding factor (CTCF) is exclusively expressed within the round and early elongating spermatids in mice, coinciding with transcriptional shutdown and the onset of histone replacement. In this pilot, feasibility grant proposal we will test the hypotheses that: 1) CTCF functions as a transcription factor as well as an organizer of spermatid genome to facilitate chromatin remodeling and 2) CTCF is essential for the completion of spermatogenesis and male fertility. We will perform ChIP-seq to determine genome-wide occupancy of CTCF in round spermatids and generate CTCF conditional knockout mice using the Cre-loxP technology to test the requirement of CTCF for spermatogenesis and male fertility. CTCF is an ideal candidate for this role because it is a multifunctional DNA binding protein with diverse roles including that of a chromatin organizer. Floxed CTCF mice as well as the male germ cell-specific cre-deleter strain (Stra8-iCre) are readily available. This proposal will explore the role of CTCF in male fertility fr the first time. Infertility affects 1 in 6 couples in the reproductive age group, with the male facor accounting for 50% of those cases. If depletion of CTCF causes sperm maturation arrest, this study will provide a novel mouse model for male infertility. Given the role that CTCF plays in establishing and / or maintaining epigenetic marks, the proposed knockout mouse may be a useful model to understand the risks involved in Assisted Reproductive Technology using incompletely developed spermatids or sperm. Thus, the studies are highly significant from the point of view of male reproductive health.

 描述（由申请人提供）：圆形精子细胞分化为精子，称为精子发生，是一个复杂的过程，涉及顶体、鞭毛和细胞核凝聚的形成。在浓缩的准备过程中，精子细胞核经历了剧烈的染色质重塑，包括全基因组转录的停止，核小体组织的解体，以及组蛋白向鱼精蛋白的转变。这个过程是男性生殖细胞所独有的。小鼠模型表明，核凝聚缺陷导致男性不育;然而，调节这一复杂的全基因组过程的机制还不清楚。我们的工作假设是，基因组组织蛋白CTCF协调伴随精子细胞分化的染色质重塑事件。进化上保守的11个锌指蛋白CCCTC结合因子（CTCF）仅在小鼠圆形和早期伸长精子细胞内表达，与转录关闭和组蛋白替换的发生相一致。在这个试点项目中，我们将测试以下假设：1）CTCF作为转录因子以及精子细胞基因组的组织者，以促进染色质重塑; 2）CTCF对精子发生和男性生育力的完成至关重要。我们将进行ChIP-seq以确定圆形精子细胞中CTCF的全基因组占有率，并使用Cre-loxP技术产生CTCF条件性敲除小鼠以测试CTCF对精子发生和雄性生育力的需求。CTCF是一个理想的候选人，因为它是一个多功能的DNA结合蛋白，具有不同的作用，包括染色质组织者。Floxed CTCF小鼠以及雄性生殖细胞特异性cre-deleter品系（Stra 8-iCre）可随时获得。本研究将首次探讨CTCF在男性生育中的作用。在育龄组中，每6对夫妇中就有1对患有不孕症，其中男性因素占50%。如果CTCF的缺失导致精子成熟停滞，本研究将为男性不育提供一种新的小鼠模型。鉴于CTCF在建立和/或维持表观遗传标记方面所发挥的作用，拟议的基因敲除小鼠可能是了解使用不完全发育的精子细胞或精子的辅助生殖技术所涉及的风险的有用模型。因此，从男性生殖健康的角度来看，这些研究非常重要。