灵长类RHOXF2 基因拷贝数差异和分子进化分析及垂体腺苷酸环化酶激活肽相关新肽的功能研究
文献类型：学位论文
| 作者 | 牛傲蕾 |
| 学位类别 | 博士 |
| 答辩日期 | 2011-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 宿兵 |
| 关键词 | 分子进化 RHOXF2 拷贝数差异 人类特有的垂体腺苷酸环化酶激活肽相关新肽人类演化 认知能力 |
| 其他题名 | Copy number variation and evolutionary analysis of RHOXF2 gene in primates and function study of PACAP-related novel peptide |
| 学位专业 | 遗传学 |
| 中文摘要 | 人类与非人灵长类在表型上存在很多差异，比如裸露的皮肤、直立行走和语言能力等。其中最大的差别在于人类的大容量大脑以及高级认知能力。人类与其近缘物种黑猩猩的基因组平均序列差异很小，那么，什么导致了我们如此不同，人类是如何起源的呢？本论文从基因组和遗传的角度探讨灵长类物种间的分子差异；从两个不同的方面着手，即RHOXF2基因的分子进化分析和人类特有的垂体腺苷酸环化酶激活肽相关新肽的功能研究。RHOXF2基因的进化历程涉及到达尔文正选择、内共生逆转录病毒重复元件、基因片段重复、拷贝数差异、基因丢失和mRNA 表达模式改变。而人类特有的垂体腺苷酸环化酶激活肽相关新肽的产生是蛋白编码序列差异的一个典型例子，同时还涉及到正选择以及一个全新的人类特有多肽的起源。 X-linked reproduction homeobox family gene, member 2 (RHOXF2) 是一个同源异型框基因，在大脑和睾丸组织中优势表达。作为X染色体上生殖相关的同源异型框基因，它调控与神经发育相关的三个基因Unc5c、Pltp和Gdap1的表达，暗示该基因可能不只与精子发生相关，还在脑发育过程中发挥重要作用。在灵长类中，RHOXF2基因快速进化；在灵长类的多个支系上存在达尔文正选择作用，特别是在人和黑猩猩共同祖先的进化分支上。在人群中的所有8个多态位点均是改变氨基酸的突变，暗示现代人群中正选择作用还在继续。在灵长类中，该基因存在快速的拷贝数变异，特别是在黑猩猩基因组中大约有6个拷贝的基因簇产生。研究表明，灵长类中RHOXF2拷贝数的变化可能是由于内共生逆转录病毒介导的重组而导致的。在黑猩猩起源过程中，甚至同源异型框结构域也受到了强烈的正选择。 垂体腺苷酸环化酶激活肽（PACAP）前体基因ADCYAP1，在人类起源过程中快速进化，推测可能通过获得一个α酰胺化位点和17个人类特有的氨基酸突变而导致了一个人类特有的41个氨基酸的多肽产生。我们将它命名为人类特有垂体腺苷酸环化酶激活肽相关新肽（human-specific PACAP-related novel peptide 41，hPRNP41），简称NP41。我们实验证明了hPRNP41在人类中确实存在，在睾丸、下丘脑和血液中均有分布。人血浆中，hPRNP41的浓度为10-13-10-14 mol/μl (0.05-0.5ng/ml)，与PACAP38的浓度相当。在健康志愿者的血浆中，它的表达量相对比较稳定，与性别和年龄无关。质谱结果表明该多肽除了生物活性必需的α酰胺化之外没有任何其它修饰。初步的功能实验表明，化学合成的NP41不能改变PACAP38和PACAP27的腺苷酸环化酶活性，表明它的功能可能与PACAP有所不同。 |
| 英文摘要 | Human being has many phenotypic differences from other non-human primates, such as bare skin, bipedal walking and language ability. However, the most significant difference is the enlarged brain and highly-developed cognitive abilities in human. It has been shown that the average genomic sequence divergence between human and chimpanzee (the closest relative of human) is very small. Hence, genetically, what makes us human has become a critical question in understanding human evolution. In this study, by utilizing the approaches in genetics and genomics, we aim to answer the question by conducting two studies, the molecular evolutionary analyses of RHOXF2 gene and functional study of human-specific PACAP-related novel peptide. The evolution process of RHOXF2 gene involves Darwinian positive selection, endogenous retroviruses repeat elements, gene segmental duplication, copy-number variation, gene deletion and mRNA expression change. The human-specific PACAP-related novel peptide is an example of protein-coding sequence change, and also involves positive selection and origin of a novel human-specific protein. RHOXF2 gene is a homeobox gene highly expressed in the brain and testis. As a reproductive homeobox X-linked family gene, it has the ability to regulate of the expression of Unc5c, Pltp and Gdap1, suggesting that it not only takes part in spermatogenesis, but also may play an important role in brain development. RHOXF2 gene evolved rapidly in primates. Multi-lineages positive selections were detected during the evolution of primates, especially during the origin of human and chimpanzee. The observed sequence polymorphisms are all non-synonymous in human populations, implying that there is on-going positive selection in contemporary human populations. Surprisingly, our study demonstrated that RHOXF2 has experienced rapid copy number changes in primates, especially in chimpanzee, in which about 6 copies were identified. The frequent copy number changes of RHOXF2 in primates are likley caused by the endogenous-retrovirus-mediated recombinations. During the origin of chimpanzee, even the homeodomain was under a strong positive selection. ThePACAP precursor gene, ADCYAP1, evolved rapidly in the human lineage, and a putative novel human-specific 41-AA peptide was originated by gaining an alpha-amidation site and 17 human specific amino acid changes. We named it as human-specific PACAP-related novel peptide 41(hPRNP41). In this study, our data suggested that hPRNP41 does exist in human. It is distributed in human testis, hypothalamus and plasma. In human plasma, the hPRNP41 concentration is about 10-13-10-14 mol/μl (0.05-0.5ng/ml), comparable to the PACAP concentration. Its concentration is relatively stable in the plasma of healthy human individuals and no variation with gender and age was observed. Mass spectrometry analysis proved that it is alpha-amidated without any other modification. The chemical synthetic hPRNP41 can not change the adenylate cyclase activity of PACAP38 and PACAP27, implying that its function is different from PACAP. |
| 语种 | 中文 |
| 公开日期 | 2011-09-21 |
| 源URL | [http://159.226.149.42:8088/handle/353002/6802]  |
| 专题 | 昆明动物研究所_比较基因组学 |
| 推荐引用方式 GB/T 7714 | 牛傲蕾. 灵长类RHOXF2 基因拷贝数差异和分子进化分析及垂体腺苷酸环化酶激活肽相关新肽的功能研究[D]. 北京. 中国科学院研究生院. 2011. |
入库方式： OAI收割
来源：昆明动物研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。