Boule基因的生物信息学分析

发布时间：2018-09-19 12:20

【摘要】：现代社会的发展为人们的生活提供了丰富的物质保证，但同时人类的生殖健康却因环境改变、生活节奏加快和压力增大而面临着巨大的考验。我国不孕不育率已经占到育龄人群的10%，由于男性因素造成的不孕不育呈现明显的上升趋势。少精、弱精以及无精子症是男性不育的主要原因，这个特殊的健康缺陷，成为导致家庭破裂、影响社会和谐的主要因素之一。因此，有关精子发生机理成为当今生殖医学领域中研究的热点。精子发生是一个高度复杂而有序的过程，从精原细胞增殖分化到精子成熟，需要经历有丝分裂、减数分裂和精子形成三个连续的阶段。在这一过程中有许多基因对其进行调控，基因突变或表达异常均可导致不育。DAZ基因家族是导致男性不育的关键候选基因之一，也是近年来被广泛研究的一个热门基因家族。Boule基因是新发现的该基因家族成员，它可能调控减数分裂的发生，Boule基因的缺失、突变或者BOULE蛋白表达异常都可能导致精子发生过程阻滞，造成精子生成障碍，导致无精子症而不育。目前，，对Boule基因的生物学特征和作用机制缺乏深入全面的研究，本文利用生物信息学方法对人、倭黑猩猩、松鼠猴、牛、小鼠、虹鳟鱼、斑胸草雀、黑腹果蝇、曼氏裂体吸虫、拟南芥十个物种中Boule基因的核苷酸序列和蛋白序列进行比较分析，利用不同物种蛋白序列构建进化树，对其同源性和进化关系进行分析。利用生物信息学ExPASy软件对其理化性质、疏水性/亲水性、信号肽、跨膜结构、卷曲螺旋、细胞定位进行分析，通过基于GOR算法的在线分析工具GOR4与PredictProtein对BOULE蛋白二级结构、功能结构域进行预测和分析，根据Pfam数据库对Boule功能以及信号通路进行预测和分析。十个物种BOULE蛋白序列比较结果显示，BOULE蛋白序列在物种进化过程中变化较大，但是在哺乳动物种间序列相似度达到90%~99%之间，具有较高的同源性。BOULE蛋白进化树分析表明，BOULE蛋白被聚为两大类，拟南芥独自为一类；其它物种为一类。BOULE蛋白生物学特征分析显示：BOULE蛋白含有283个氨基酸，分子量为31.299KD，等电点为6.59，为酸性蛋白，属于非分泌型蛋白，属于非跨膜蛋白质；BOULE蛋白存在于精原细胞的细胞质，细胞核，线粒体中；二级结构主要有α-螺旋(9.19%)、延伸链（22.26%）、无规则卷曲（68.55%）；结构域分析结果表明BOULE蛋白含有RRM结构域。对其功能预测分析显示：BOULE蛋白与Pum2蛋白相互作用，调控细胞周期蛋白的转录；同时与减数分裂相关蛋白DAZ1、CDC25A、CDC25C相互作用，调控精原细胞的分化和减数分裂的发生，因此，Boule基因是精子细胞分化所必不可少的重要调控基因；本文通过生物信息学方法对BOULE蛋白进化过程中的序列同源性、理化性质及其在精子发生过程中的作用机理进行分析和预测，有利于我们系统了解Boule基因在精子发生中的作用，为诊断和治疗少精、弱精以及无精症提供理论依据，在人类精子发生的研究中具有非常重要的意义。
[Abstract]:The development of modern society has provided abundant material guarantee for people's life, but at the same time, human reproductive health is facing a huge test because of environmental changes, quickened pace of life and increased pressure. Oligospermia, asthenospermia and azoospermia are the main causes of male infertility. This special health defect has become one of the main factors leading to family breakdown and affecting social harmony.
Spermatogenesis is a highly complex and orderly process, from spermatogonial proliferation and differentiation to sperm maturation, which involves three consecutive stages: mitosis, meiosis and spermatogenesis. Boule gene is a newly discovered member of this gene family. It may regulate meiosis. Boule gene deletion, mutation or abnormal expression of BOULE protein may lead to spermatogenesis arrest and spermatogenesis disorder. Lead to azoospermia and infertility.
At present, there is no thorough and comprehensive study on the biological characteristics and mechanism of Boule gene. The nucleotide and protein sequences of Boule gene in ten species of human, bonobo chimpanzee, squirrel monkey, cattle, mouse, rainbow trout, zebra finch, Drosophila melanogaster, Schistosoma mansoni and Arabidopsis thaliana were comparatively analyzed by bioinformatics. The phylogenetic tree was constructed by using different protein sequences and their homology and evolutionary relationships were analyzed. The physiochemical properties, hydrophobicity/hydrophilicity, signal peptide, transmembrane structure, coiled helix and cell localization of BOULE protein were analyzed by using bioinformatics software ExPASy. Boule function and signaling pathway were predicted and analyzed according to Pfam database. Comparison of BOULE protein sequences of ten species showed that BOULE protein sequences varied greatly during the evolution of species, but the similarity between mammalian species was between 90% and 99%. BOULE protein phylogenetic tree analysis showed that BOULE proteins were grouped into two major groups, Arabidopsis alone was one; other species were one. Biological characteristics of BOULE protein showed that BOULE protein contained 283 amino acids, molecular weight was 31.299 KD, isoelectric point was 6.59, it was acidic protein, belonged to non-secretory protein, belonged to non-transmembrane protein. BOULE protein was found in the cytoplasm, nucleus and mitochondria of spermatogonia; the secondary structure was mainly alpha-helix (9.19%), elongated chain (22.26%) and irregular convolution (68.55%); domain analysis showed that BOULE protein contained RRM domain. Cyclin transcription; interacts with meiosis-related proteins DAZ1, CDC25A and CDC25C to regulate the differentiation and meiosis of spermatogonia. Therefore, Boule gene is an essential regulatory gene for sperm cell differentiation. The analysis and prediction of physical and chemical properties and their mechanism in spermatogenesis will help us to understand the role of Boule gene in spermatogenesis systematically and provide theoretical basis for the diagnosis and treatment of oligospermia, asthenospermia and azoospermia.
【学位授予单位】：内蒙古师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：Q811.4;R698.2

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