Molecular variation and evolution of the tyrosine kinase domains of insulin receptor IRa and IRb genes in Cyprinidae  

作　　者：KONG XiangHui WANG XuZhen HE ShunPing 

机构地区：[1]College of Life Science, Henan Normal University, Xinxiang 453007, China [2]Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China

出　　处：《Science China(Life Sciences)》2011年第7期626-633,共8页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 30770299 and 30530120);the Development Plan of the State Key Fundamental Research of China (Grant No. 2004CB117402)

摘　　要：The insulin receptor （IR） gene plays an important role in regulating cell growth, differentiation and development. In the present study, DNA sequences of insulin receptor genes, IRa and IRb, were amplified and sequenced from 37 representative species of the Cyprinidae and from five outgroup species from non-cyprinid Cypriniformes. Based on coding sequences （CDS） of tyro- sine kinase regions of IRa and IRb, molecular evolution and phylogenetic relationships were analyzed to better understand the characteristics of IR gene divergence in the family Cyprinidae. 1Ra and IRb were clustered into one lineage in the gene tree of the IR gene family, reconstructed using the unweighted pair group method with arithmetic mean （UPGMA）. IRa and IRb have evolved into distinct genes after IR gene duplication in Cyprinidae. For each gene, molecular evolution analyses showed that there was no significant difference among different groups in the reconstructed maximum parsimony （MP） tree of Cyprinidae; IRa and 1Rb have been subjected to similar evolutionary pressure among different lineages. Although the amino acid sequences of IRa and IRb tyrosine kinase regions were highly conserved, our analyses showed that there were clear sequence variations between the tyrosine kinase regions of IRa and IRb proteins. This indicates that IRa and IRb proteins might play different roles in the insulin signaling pathway.The insulin receptor (IR) gene plays an important role in regulating cell growth,differentiation and development.In the present study,DNA sequences of insulin receptor genes,IRa and IRb,were amplified and sequenced from 37 representative species of the Cyprinidae and from five outgroup species from non-cyprinid Cypriniformes.Based on coding sequences (CDS) of tyrosine kinase regions of IRa and IRb,molecular evolution and phylogenetic relationships were analyzed to better understand the characteristics of IR gene divergence in the family Cyprinidae.IRa and IRb were clustered into one lineage in the gene tree of the IR gene family,reconstructed using the unweighted pair group method with arithmetic mean (UPGMA).IRa and IRb have evolved into distinct genes after IR gene duplication in Cyprinidae.For each gene,molecular evolution analyses showed that there was no significant difference among different groups in the reconstructed maximum parsimony (MP) tree of Cyprinidae;IRa and IRb have been subjected to similar evolutionary pressure among different lineages.Although the amino acid sequences of IRa and IRb tyrosine kinase regions were highly conserved,our analyses showed that there were clear sequence variations between the tyrosine kinase regions of IRa and IRb proteins.This indicates that IRa and IRb proteins might play different roles in the insulin signaling pathway.

关 键 词：insulin receptor gene tyrosine kinase domain CYPRINIDAE 

分 类 号：Q51[生物学—生物化学] Q578