非洲爪蟾Brunol1 基因的功能以及文昌鱼肌动蛋白基因家族扩增的研究
文献类型：学位论文
| 作者 | 魏云虎 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009-06 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 毛炳宇 |
| 关键词 | BRUNOL 非洲爪蟾 Morpholino 文昌鱼 肌动蛋白 进化 |
| 其他题名 | The study on Brunol1’ s function in Xenopus laevis and expansion of the actin gene family in amphioxus |
| 中文摘要 | BRUNOL 蛋白又称CELF（CUG-BP and ETR3 like factor）是一种典型的RNA 结合蛋白，它的N 端含有两个连续的RNA 识别结构域（RNA recognition motif，RRM)， C 端有一个RRM 结构域。主要参与对可变剪切、翻译、降解和编辑等基因表达转录后水平的调节。迄今在人类中已发现6 个Brunol 基因家族成员，即Brunol1-6；在非洲爪蟾中已发现了5 个：Brunol1-5。近期，我们克隆了爪蟾的Brunol1-5 并研究了它们在非洲爪蟾早期胚胎发育过程中的时空表达图式。结果显示，与以往研究结果一致， Brunol1 基因高量、特异地在神经管中表达，提示Brunol1 基因可能对于爪蟾的神经系统的发生和发育发挥着重要的作用。本实验利用Morpholino 和过表达等手段研究了爪蟾Brunol1 基因对于爪蟾早期胚胎发育的影响。结果显示，在下调和过表达Brunol 1 基因的情况下都会导致胚胎出现体轴弯曲，眼睛和头部发育不全等表型。而将 Brunol1 基因特异的Morpholino 与它的mRNA 共注射时可以明显挽救这一表型。我们通过原位杂交实验，检测了一些爪蟾神经系统的标记基因在Brunol1 过表达胚胎中的表达情况，结果发现过表达Brunol1 基因能显著地下调Krox-20, N-tubulin, Lhx2, Pax6 等的表达，而Sox2 和Otx2 的表达却未受影响。这说明Brunol1 的异常表达确实影响到了神经系统发育过程的信号调控网络，导致胚胎发育的畸形。该结果将有助于阐述Brunol1 基因对于脊椎动物神经系统发生的意义。肌动蛋白是一种分布广泛而且在进化上十分保守的蛋白，它是构成细胞骨架的关键组分。通常人们将肌动蛋白分成肌肉型和胞质型两种类型，它们各自行使着不同的功能。在此，我们通过对古老的脊索动物文昌鱼的肌动蛋白基因家族进行系统的分析发现，文昌鱼中该基因家族成员多达30 多个，而且它们中很多都有连锁现象；进化分析的结果显示，文昌鱼的肌动蛋白基因家族通过串联重复序列的复制发生扩增；从结构上看，它们的基因结构多样化, 包含2-7 个外显子；同时，我们还克隆了两个不同的文昌鱼肌肉型的肌动蛋白基因，并进一步比较了它们在文昌鱼早期胚胎中的表达图式。结果显示，这两个基因在表达上有着细微的差别，这提示文昌鱼肌动蛋白基因家族成员在功能上的分化。该结论将有助于阐述肌动蛋白基因家族的进化以及它们在脊索动物发育的中所扮演的功能。 |
| 英文摘要 | BRUNOL(Bruno-like protein), also named CELF(CUG-BP and ETR3 like factor), is a typical RNA binding protein with two consecutive RNA recognition motifs(RRM) in the N terminal and one in the C terminal. It has many functions in the post-transcriptional regulation of gene expression, such as alternative splicing, translation, degradation and editing. Until now, 6 members of Brunol family have been found in human, namely, Brunol 1-6 and 5 in Xenopus laevis:Brunol1-5 . Recently, we cloned all the 5 members of Brunol family in Xenopus laevis and found that Brunol1 is robustly and specifically expressed in the neural tube. To study the role of Brunol1 in neural development, we did loss-of-function and overexpression experiments in Xenopus embryos. Blocking of Brunol1 by specific morpholino leads to severe embryonic defects with curved bodies and defected eyes. These phenotypes can be rescued by co-injected Brunol1 mRNA. Interestingly, overexpression of Brunol1 can give rise to abnormal embryos with curved bodies. When injected in the head region, the head development was severely blocked. Through in situ hybridization, we checked the expression of several neural specific markers in Brunol1 injected embryos. We found that overexpression of Brunol1 clearly inhibited the expression of Krox-20, N-tubulin, Lhx2, Pax6, but not that of Sox2 and Otx2, suggesting a specific role of Brunol1 in neural differentiation. These results are instructive for elucidating Brunol1’s role in neurogenesis in vertebrate. Actins are a small family of ubiquitous proteins that are essential cytoskeletal components and are highly conserved during evolution. Actins are usually divided into two classes, the cytoplasmic and muscle actins, which have different functional roles. Here we systematically analyzed the actin genes in the genome of the primitive chordate amphioxus (Branchiostoma floridae). We found that amphioxus contains more that 30 actin genes, many of which are linked. Phylogenetic analysis suggest the amphioxus actin genes have clearly undergone expansion through tandem and clusteral duplications. The actin genes’ structure also varies a lot, containing 2 to 7 exons. We also cloned two muscle types of actin genes from the amphioxus and compared their expression patterns during early development. The slight difference in their expression suggests functional diversification of these actin genes. Our results shed light on the evolution both of actin genes themselves and of their functional roles in chordate development. |
| 语种 | 中文 |
| 公开日期 | 2010-10-22 |
| 源URL | [http://159.226.149.42:8088/handle/152453/6291]  |
| 专题 | 昆明动物研究所_发育生物学 |
| 推荐引用方式 GB/T 7714 | 魏云虎. 非洲爪蟾Brunol1 基因的功能以及文昌鱼肌动蛋白基因家族扩增的研究[D]. 北京. 中国科学院研究生院. 2009. |
入库方式： OAI收割
来源：昆明动物研究所
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