【作者】 潘雪霞；

【导师】 邵健忠；

【作者基本信息】 浙江大学 ， 细胞生物学， 2004， 硕士

【摘要】 QM基因是从人维尔姆斯肿瘤杂合细胞中首次分离到的，最初认为与人维尔姆斯肿瘤抑制相关。在随后的研究中，人们发现QM基因产物还具有c-jun等原癌基因转录调节、Src家族信号转导、核糖体构型与功能维持等多种生物学活性，它参与细胞生长、分化、发育和凋亡等重要生命活动过程。QM同源基因广泛地存在于动物、植物以及真菌界。结构分析结果表明，QM同源基因在进化上是比较保守的。在小鼠和人中，QM基因是以多拷贝形式存在的，并且它在多种组织中都有表达。虽然已有的研究表明QM是一种多功能基因，但有关其具体的生物学功能与作用机制尚不很清楚。迄今，鱼类中尚未见QM基因的研究报道。本文应用生物信息学和分子克隆等技术，首次从鱼类中克隆出QM基因，为QM的分子进化以及生物学功能的深入研究打下基础。 我们首先通过电子克隆获得了斑马鱼QM基因序列信息，然后构建了草鱼头肾和脾脏λZAPII cDNA文库，利用QM基因的保守区域和载体序列，设计了系列特异性引物，通过套式和锚定PCR，克隆了草鱼QM同源基因，命名为GcQM。该cDNA基因全长751bp，开放阅读框编码215个氨基酸，预测的蛋白质大小为24.5kDa。GcQM编码的多肽与人QM多肽相比，相似性和同一性分别高达96％和92％；与果蝇相比，也分别有86％和76％。 我们对GcQM在草鱼主要组织细胞如脑、心肌、头肾、脾脏、肝脏、肠和肌肉中的表达进行了研究，同时对草鱼经出血病病毒(GCHV)、嗜水气单胞菌感染后各组织中QM的诱生型表达情况作了探讨。结果表明，GcQM在草鱼脑、心肌、脾脏中都有表达，其中脑和心肌中表达量很高，在肌肉、肠、头肾、肝脏中则没有表达。然而，在草鱼出血病病毒诱导组的头肾和肝脏中，GcQM表达上调；在嗜水气单胞菌诱导组的头肾中也出现相似情况。这一结果提示QM的表达是可诱导的，它与鱼类免疫功能的关系值得作深入研究。更多还原

【Abstract】 QM is a human cDNA originally isolated as a transcript elevated in a nontumori-genenic Wilms’ tumor microcell hybrid, relative to the tumorigenic parental cell line. It has been cloned from species encompassing members of the plant, animal, and fungal kingdoms. Sequence comparison indicates that QM has been highly conserved throughout eukaryotic evolution. QM is a member of a multigene family in both mouse and man, is expressed in a broad range of tissues, and is downregulated during adipocyte differentiation. Jif-1, a chicken homolog of QM, has been reported to interact with the protooncogene c-Jun, and to inhibit transactivation of AP-1 regulated promoters in vitro. Furthermore, disruption of the yeast QM homolog is lethal. Although these studies suggest that the QM gene product plays an important role within the normal cell, the precise role of QM has remained elusive.In the present work, a gene homologous to QM is isolated from a lambda ZAPII grass carp ( Ctenopharyngodon idellus ) spleen and head kidney cDNA libaray using primers to very conserved regions of the QM gene and to the sequence of the lambda ZAPII vector. It is designated GcQM. The GcQM cDNA measures 751 nucleotides in length and encodes a polypeptide of 215 residues with a corresponding Mr of 24.5 kDa. Analysis of the product of GcQM revealed 96%similarity and 92% identity with QM protein from Homo sapiens and 86% and 76%, respectively, with Drosophila melanogaster.Analysis of GcQM expression in various adult tissues, such as brain, cardiac muscle, head kidney, spleen, liver, muscle, intestines, and is differentially expressed throughout these tissues. In control column, GcQM is strongly expressed in cardiac muscle and brain. However, it is not detectable in other tissues. The GcQM protein can be detected in head kidney and liver when treated with GCHV. While treated with Aeromonas hydrophila, it also can be found in head kidney. This pattern of QM expression suggests that GcQM product may be involved in some immunity function.更多还原