Abstract: The complete cDNA encoding yak insulin like growth factor 1 receptor (IGF-IR) gene was cloned with RT-PCR and homologous cloning methods. Sequence analysis showed that the entire coding region was 4 104 bp in length encoding 1 367 amino acids with a putative mass of 154.95 ku and pI of 5.71. Compared to IGF-IR gene sequence from cattle, there were 20 base changes in yak IGF-IR gene, including 2 substitutions for G-T, 2 transitions for G-A, 7 transitions for C-T, 3 transitions for A-G and 6 transitions for T-C, respectively. In addition, amino acid changed at 3 sites (G6R, T29I and S30I). The phylogenetic analysis revealed that yak IGF-IR gene had high homology (> 92%)with that of cattle, pig, human, dog, mouse and chimpamzee, which were classified into the same branch. The secondary structure predication indicated that yak IGF-IR protein might have the typical domains of the IGF-IR family, containing the furin-like cysteine rich region (FU), fibronectin type Ⅲ domain (FN3), transmembrane domain (TM), and tyrosine kinase domain (TyrKc), respectively. 3D model showed the mature fragment in yak IGF-IR had 98.68% homology with human IGF-IR. The present results provided the valuable foundation for further studies on yak IGF-IR functions.

Key words: Yak, IGF-IR gene, Cloning, Sequence analysis

CLC Number: 

• Q78

• S823