【作者】 姚婕；

【导师】 王继文；

【作者基本信息】 四川农业大学 ， 动物遗传育种与繁殖， 2007， 硕士

【摘要】 极低密度脂蛋白受体(Very low-density lipoprotein receptor，VLDLR)是低密度脂蛋白受体(Low-density lipoprotein receptor，LDLR)家族的一员，主要功能是结合富含载脂蛋白E的脂蛋白参与甘油三酯的代谢。本试验以朗德鹅和天府肉鹅为研究对象，用生物信息学的方法对鹅VLDLR亚型的序列特点、结构和功能进行分析和预测。使用RT-PCR方法研究鹅VLDLR基因的表达特性，以及填饲对VLDLR基因表达的影响和可能机理。研究结果表明：1．鹅VLDLR基因存在两个亚型，Ⅰ型VLDLR核苷酸序列与兔、大鼠、小鼠、人同源性分别为82％、81％、81％、80％，氨基酸同源性分别为80％、77％、77％、78％；Ⅱ型VLDLR核苷酸序列与鸡、兔、大鼠、小鼠、人同源性分别为90％、82％、81％、81％、80％，氨基酸序列同源性分别为92％、70％、70％、80％、79％。2．鹅Ⅱ型VLDLR比Ⅰ型VLDLR缺少30个氨基酸残基，人、大鼠、小鼠、兔、牛缺少28个氨基酸残基。Ⅱ型VLDLR缺失区域为O-linked糖链域，该区域的缺失可能对VLDLR的结构和功能产生影响。3．鹅VLDLR跨膜域与鸡相比有2个氨基酸变异位点，与哺乳动物相比存在6个氨基酸变异位点，多为同极性的氨基酸变异。鹅VLDLRO-linked糖链域与鸡比有1个氨基酸变异位点，与哺乳动物相比存在9～13个氨基酸变异，其中包含丝氨酸、苏氨酸的变异，这种变异可能会影响O-linked糖链域的O糖基化。4．VLDLR两亚型在鹅腹脂、皮脂、腿肌中均有表达，且腿肌的表达量高于脂肪组织。在腿肌中，Ⅰ型VLDLR为主要表达受体；在脂肪组织中，两亚型的表达无显著差异。5．Ⅰ型VLDLR在肌肉、脂肪等脂肪代谢活跃的组织高表达，而且Ⅰ型VLDLR与VLDL、β—VLDL的结合和摄取能力高于Ⅱ型VLDLR，提示Ⅰ型VLDLR与组织的脂质代谢水平相关联。Ⅱ型VLDLR，根据相关资料推测可能在组织分化和生长发育过程中起重要作用。6．填饲后，鹅机体可根据体内脂质代谢的变化对VLDLR亚型的表达量进行调节。更多还原

【Abstract】 The very low-density lipoprotein receptor (VLDLR) is a member of LDLR family, the main function is participating in triglyceride metabolism by bounding with the triacylglycerol-rich lipoprotein. In this study, with the experiment objects of Landes goose and Tianfu meat goose, A series of bioinformatics analyses were performed to analysis and predict the sequence characteristic, the structure and function of goose VLDLR two isoforms. The expression characteristic of VLDLR two isoforms in geese were investigated by RT-PCR method. The influence of force-feeding on the expression of VLDLR gene in geese and its possible mechanism were analyzed. The results were as following:1. The goose VLDLR gene had two isoforms. TypeⅠVLDLR had a similarity of 82%, 81%, 81% and 80% at nucleic acid level, 80%, 77%, 77% and 80% at the amino acid level with rabbit, rat, mouse and human. TypeⅡVLDLR had a similarity of 90%, 82%, 81%, 81% and 80% at nucleic acid level, 92%, 70%, 70%, 80% and 79% at the amino acid level with chicken, rabbit, rat, mouse and human.2. The goose typeⅡVLDLR lacks 30 amino acid, but human, rat, mouse, rabbit, bovine lacks 28 amino acid. The absent domain of typeⅡVLDLR was O-linked sugar domain, the absent of which could affect the structure and function of VLDLR.3.There were two variation sites of amino acid between goose and chicken, six variation sites between goose and mammalian in transmembrane domain of goose VLDLR, which were the same polarity amino acid variation. In O-linked sugar domain of goose VLDLR, there were one variation sites of amino acid between goose and chicken, 9～13 variation sites of amino acid between goose and mammalian, which included serine and threonine and influenced the O- glycosylation of O-linked sugar domain.4.TypeⅠVLDLR and typeⅡVLDLR were both expressed in abdomen adipose tissue, subcutanceous adipose tissue and skeletal muscles. The expression abundance of VLDLR in skeletal muscles was higher than in adipose tissue. The expression of typeⅠVLDLR was predominant in skeletal muscles. There was no significant difference of expression abundance between typeⅠVLDLR and typeⅡVLDLR in adipose tissue.5.TypeⅠVLDLR was mainly expressed in muscles and adipose tissue where lipid metabolism was more activity. TypeⅠVLDLR bound with relative higher affinity to VLDL andβ-VLDL, and internalizes much more lipoprotein into cells than typeⅡVLDLR. It indicated that typeⅠVLDLR was correlated with the level of lipid metabolism. It was presumed that TypeⅡVLDLR played an important role in growth and development of tissues, cell differentiation.6. After overfeeding, the expression abundance of geese VLDLR isoforms could be regulated according to the change of lipid metabolism in vivo.更多还原