促葡萄糖转运蛋白基因家族的分子进化研究

Studies on the Molecular Evolution of Glucose Transporter Gene Family

葡萄糖转运蛋白是一个在结构上相似功能上不同的多基因家族（ＧＬＵＴ１－ＧＬＵＴ５）。由于这一组蛋白和体内的葡萄糖利用有关，因此被认为是糖尿病胰岛素抵抗（抗性）的一个候选基因。本文比较了不同种生物这一基因家族的氨基酸和核苷酸顺序；推测了亲水性和疏水性分布；计算了蛋白质和核苷酸的进化距离，并在此基础上构建了分子进化树。研究表明：这一基因家族具有高度的同源性、极为相似的亲水性和疏水性分布以及结构的对称性。提示这一基因家族起源于一个共同的祖先并可能通过基因的重复而形成。这一进化机制可能有利于氨基酸结构的稳定及抵抗突变的作用。由于邻元法构建的进化树其分支长度存在差异，提示在这一基因家族的进化过程中，各分支上的进化速率并不相同。蛋白质进化距离和核苷酸进化距离所构建进化树的差异提示了在基因组中可能存在隐匿替换。两种方法构建的进化树都提示了ＧＬＵＴ１、３、４在结构和功能上要更为保守。

Glucose transporter gene family which was involved in the glucose metabolism in the body has been considered as a candidate gene in the development of diabetes mellitus.We compared the nucleotide and amino acid sequences of the family in different species;deduced the hydrophilicity and hydrophobicity distribution of the amino acid; calculated the genetic distance and constructed the phylogenetic trees by UPGMA and N-J method.The results showed that the members of glucose transporter gene family are homologous;all the members of this family have a similar topology;It is suggested that the family may derived from a remote commom ancester in which the gene duplication events of different origins took place;this evolutionary process is advantageous to the stability of the structure.The different branch length in the phylogenetic trees constructed by the N-J method indicated difference of evolutionary rates in the process of evolution.Also,the difference between the trees at protein and nucleotide level may result from the hidden substitution in the genome.