2014-11-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/710466摘要：非整倍體，指染色體數目異常，估計至少發生在20%以上的人類受精卵母細胞，因此它是導致流產，胎兒先天缺陷和智力遲鈍的主要原因。這些核型異常主要是由於卵母細胞減數分裂過程中染色體分離異常而產生，然而其分子機制仍是未知。 Ikbkap基因編碼IKAP/Elp1蛋白質，最初認為是RNA聚合&#37238;II相關轉錄延伸因子之一。從其在小鼠的發育表達模式，我們推測Ikbkap基因參與生殖細胞發育過程。在Ikbkap基因剔除小鼠模式中，我們發現剔除Ikbkap基因會影響公鼠生殖細胞減數分裂過程，進而導致不孕。此外Ikbkap基因缺陷睾丸在tRNA分子wobble位置上尿嘧啶修飾減少，我們推測進而影響轉譯效果而導致減數分裂相關基因的下調。不同於公鼠，我們的初步研究結果發現Ikbkap基因缺陷母鼠仍有生育能力但生育力下降，並高頻率地在卵母細胞發現非整倍體。 此計畫中，我們提出Ikbkap基因可能經由tRNA分子wobble位置上尿嘧啶修飾調控轉譯過程，並進而調控卵子發育及其後減數分裂的假設。我們預計達到三項具體目標：(一)分析Ikbkap基因在卵母細胞發育過程中的表達模式，(二) 剖析Ikbkap基因在小鼠卵母細胞減數分裂過程中的角色，(三) 探討Ikbkap基因導致非整倍體產生的分子機制。我們將綜合各種分子生物學、細胞生物學、小鼠遺傳學、生物化學等技術，以驗證我們的理論。 我們預期將找出Ikbkap基因如何影響哺乳動物的卵子發育，並揭露一種新的分子機制調控卵母細胞減數分裂。此研究成果將會對生殖醫學，tRNA生物學和腫瘤生物學等研究領域有顯著的貢獻及影響。<br> Abstract: Aneuploidy, an aberrant number of chromosomes, has been estimated to occur in up to 20% of fertilized human oocytes; thus, it is the leading cause of pregnancy loss, congenital defects and mental retardation. These karyotypic aberrations are largely due to chromosome segregation abnormalities arising during female meiosis. However, the molecular mechanisms underlying proper and aberrant chromosome segregation in mammalian oocytes remain largely unknown. Ikbkap gene encodes IKAP/Elp1, a subunit of the Elongator complex that was initially described as an RNA polymerase II-associated transcription elongation factor. Based on its developmental expression patterns, we hypothesized that Ikbkap participates in germ cell development. Indeed, we have recently discovered its function in male reproduction. Male mice with targeting deletion of Ikbkap in germ cells display defects in meiotic progression which leads to infertility. In addition, Ikbkap-mutant testes exhibit defects in wobble uridine tRNA modification, which might contribute to the down-regulation of meiosis-specific genes. Unlike male mutants, our preliminary results show that Ikbkap female mutant mice are subfertile and exhibit high rates of aneuploidy in oocytes. In this study, we hypothesize that Ikbkap play critical roles in female germline and propose three specific aims to delineate how it controls gene expression and cellular functions during oogenesis. Three specific aims are proposed: (Aim 1) Analyze the expression pattern of Ikbkap during oocyte development, (Aim 2) Determine the role of Ikbkap during meiosis in mouse oocytes, and (Aim 3) Characterize the molecular mechanism underlying the aneuploidy exhibited by Ikbkap female mutants. A wide array of approaches including genetics, genomics, biochemistry and advanced imaging will be employed to test the hypothesis. With the completion of this proposed study, we anticipate providing new insights on how Ikbkap impacts mammalian oogenesis and uncover a novel regulation mechanism controlling female meiosis. The finding of this study will have significant impacts on multiple research fields, including reproductive medicine, tRNA biology and cancer biology.Ikbkap/Elp1減數分裂小鼠卵母細胞非整倍體Ikbkap/Elp1meiosisoocytemouseaneuploidy