Abstract:

【Objective】 Lactoferrin play a very important role in antibiosis, antivirus, antitumor and immunomodulation for mammal. The coding region of LF gene of Tian Zhu white yak was cloned, and it’s molecular characteristics were analyzed in the study. 【Method】 Using mammary tissue of Tian Zhu white yak as material, the cDNA sequence containing coding region of LF gene was cloned by RT-PCR. The cDNA of LF gene of Tian Zhu white yak obtained by cloning was compared to corresponding sequence of cow. Sequence alignment and evolutionary tree were analyzed on Tian Zhu white yak and other species. The structure and properties of LF gene of yak were predicted. 【Result】 The 2 344 bp length cDNA of LF gene of Tian Zhu white yak was cloned for the first time, and the length of coding region of LF gene is 2 124 bp, coding 708 amino acids. There are 15 mutations in the cDNA between yak and cow, 12 mutations being in coding region of LF gene, causing 4 amino acid mutations in LF protein. There is high homeology of LF protein among different species. Amino acid similarities of LF protein compared yak to cow, human, mouse, goat, sheep, pig, dog, horse, camel, chimpanzee and chicken are 99.4%, 69.5%, 63.5%, 92.4%, 91.5%, 72.9%, 69.1%, 72.6%, 75.3%, 69.5% and 50.9%, respectively. The evolutionary tree of all species complies with laws of evolution. Homogenous 3D model of LF obtained by predict shows that LF protein forms two similar and symmetrical leaves, namely N-leaf and C-leaf, connected by an Alpha helix impressionable to prolease, and LF protein presents “two-folium-ginkgo-shaped” structure. 【Conclusion】 The coding region of LF gene in Tian Zhu white yak was cloned for the first time, and its molecular characteristics were shown. This work has laid an important foundation for researches of genetic engineering and protein function of LF protein of yak.

Key words: yak, LF gene, clone, molecular characteristics