体细胞中核糖体基因活性对重编程的影响研究

项目名称： 体细胞中核糖体基因活性对重编程的影响研究

项目编号： No.31271590

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 生物科学

项目作者： 雷蕾

作者单位： 哈尔滨医科大学

项目金额： 78万元

中文摘要： 真核生物基因组中存在大量重复排列的核糖体基因（rDNA），rDNA转录成rRNA前体，再加工形成核糖体组装的成分。细胞的生长和增殖依赖足够的核糖体以维持蛋白质的合成。随着发育和分化rDNA逐渐发生沉默，在体细胞中仅50%的rDNA拷贝具有转录活性。目前无论是体细胞克隆还是诱导多潜能干细胞的重编程，效率都很低。这两种重编程过程都需要去除体细胞的分化修饰，使之转变为未分化的状态。重编程过程能否开启沉默的rDNA转录，从而产生充足的rRNA以保障核糖体和蛋白的合成，这可能和开启发育关键基因的转录同样重要。本次课题我们拟通过rRNA合成、加工、DNA甲基化、组蛋白乙酰化等多个层面比较不同细胞rDNA的转录活性，分析其对体细胞核移植及iPS建系过程中重编程的影响，探讨改变成纤维细胞rDNA活性状态对重编程效率的促进，解析重编程过程的表观调控，为克隆和iPS技术的更好应用奠定基础。

中文关键词： 核糖体基因；重编程；体细胞核移植；诱导多潜能干细胞；小鼠

英文摘要： Eukaryotic cells contain several hundred ribosomal RNA genes (rDNA), they transcript to pre-rRNA and then process to become the components of ribosome. Cell growth and proliferation requires enough ribosome to maintain protein synthesis. Only about 50% of the rDNA copies are actually expressed in somatic cells, other rDNA was gradully silenced during development and differentiation. Up to now, reprogramming of somatic cells, such as nuclear transfer cloning (SCNT) or induced pluripoential stem cells (iPS), is still an unefficient event. The reprogramming needs to eliminate the modification of somatic cells during their differentiation, and initiate the undifferentiated state. Reactivation of silenced rDNA may be as same important as reactivate the critial genes for early development, which ensure to synthesize reasonable amount of ribosome and proteins. In the present study, we are going to compare state of active rDNA in different types of cells, analyze their rRNA synthesis, processing, rDNA methylation and histone acetylation. Then we will correspond the effects of rDNA activity with the reprogramming process of SCNT and iPS. Finally we will overexpress or inhibit rDNA transcription, and try to explain whether epigenetic modification of rDNA plays key role in reprogramming of fibroblast cells. We believe our

英文关键词： ribosome gene；reprogramming；SCNT；iPS；mouse