The Identification And Expression Of VEGF Gene In Different Organs And Different Altitude Of Eurasian Tree Sparrows (Passer Montanus)

In animals, vascular endothelial growth factor (VEGF) is an important growthfactor, which functions to stimulate physiological and pathological angiogenesis,maintain vascular fuction, induce endothelial cells growth, and regulate vascularpermeability. In this study, we cloned the VEGF gene in Eurasian tree sparrows(Passer montanus) and investigated the expression of the VEGF mRNA in differentorgans. Moreover, we compared the expression of VEGF mRNA between lowaltitude population and the Tibetan Plateau population of Eurasian tree sparrows. Ourresults showed:(1) In Eurasian tree sparrows, the nucleotide sequence of VEGF was651bp, thehomology was97%between Eurasian tree sparrows and Red Junglefowl (Gallusgallus), Quail (Coturnix sp.). The homology was69-94%between Eurasian treesparrows and different species in Squamata, reptiles. And no homology was foundbetween Eurasian tree sparrow and bony fish, amphibian, and mammal.(2) In Eurasian tree sparrows, the VEGF amino acid sequence contained216amino acids, which had Mw of30668.161Da, and pI of8.555. The VEGF amino acidsequence showed97%homology between Eurasian tree sparrows and Red Junglefowl,and showed98%homology between Eurasian tree sparrows and Rock Pigeon(Columba livia). The homology was55%between Eurasian tree sparrows and zebrafish (Danio rerio). The VEGF amino acid sequence showed67%homology betweenEurasian tree sparrows and Western clawed frog (Xenopus Silurana), and showed68%homology between Eurasian tree sparrows and African clawed frog(Xenopuslaevis). The homology was64-78%between Eurasian tree sparrows and differentspecies in Squamata, reptiles.And the VEGF amino acid sequence showed63-77%homology between Eurasian tree sparrow and mammals. Our results showed thehomology of amino acid sequence of the VEGF reached55-98%, which suggestedthat the gene with specific function remained highly conserved and convergent duringthe long-term evolution. (3) In Eurasian tree sparrows, the expression of VEGF mRNA in liver wassignificantly higher than those from kidney, brain and lung, and significantly higher inheart than those from brain and lung. The expression of VEGF mRNA in gonad issignificantly lower than those from liver, kidney, heart, brain and lung. Our resultsindicated that the expression of VEGF mRNA may be related to the strength andintensity of metabolism, and the state of growth.(4) The expression of VEGF mRNA in lowland Eurasian tree sparrows wassignificantly higher than those from highland (the Tibetan Plateau) population. Howthe birds from the Tibetan Plateau regulate their VEGF gene and protein to deal withthe hypoxia environments are interesting and remain to be further determined.