Abstract：Abstract Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated nuclear transcriptional factor, which plays an important role in regulating lipid metabolism. This study was carried out to clone the full-length cDNA of pigeon (Columba livia) PPARγ gene, analyze the protein structures, physical, chemical properties and their functional domain structures which encoded by PPARγ gene, and reveal its tissue expression pattern. In our experiment, rapid-amplification cDNA ends (RACE) was used to obtain pigeon PPARγ cDNA. The structure and function of PPARγ gene was analyzed by bioinformatics methods. Real-time PCR was performed to detect PPARγ mRNA expression levels in various tissues. The results showed that the full-length of pigeon PPARγ (GenBank No. KU166859.2) cDNA was of 1 846 bp including a 1 428 bp ORF, 63 bp 5'UTR and 355 bp 3'UTR. The ORF encoded a polypeptide of 475 amino acids, with a calculated relative molecular mass of 54.438 79 kD, pI of 6.19 and an average of hydropathicity -0.287. The predicted protein of pigeon PPARγ was composed of 7 661 atoms with the formula of C2436H3840N644O714S27. Structure prediction showed that there were 2 zinc finger structures and a ligand binding domain in the pigeon PPARγ protein. The deduced amino acid sequence of pigeon PPARγ shared 97%, 97%, 96%, 96%, 96%, 96%, 96%, 92%, 91%, 90% and 64% identities with those of Cuculus canorus, Anas platyrhynchos, Melopsittacus undulates, Taeniopygia guttata, Meleagris gallopavo, Gallus gallus, Coturnix japonica, Sus scrofa, Homo sapien, Mus musculus and Danio rerio, repectively. Phylogenetic relationship analysis indicated that all birds and mammals each formed a large branch, and zebrafish formed another independent branch. Columba livia was closely related with Cuculus canorus and Anas platyrhynchos, which was similar to the results of the biological classification. Real-time PCR analysis revealed that the mRNA level of pigeon PPARγ was highest in lung and abundant in kidney, liver, spleen and heart, while relatively low in muscle. The results showed the full-length cDNA sequence, molecular characteristics and tissue-specific distribution of pigeon PPARγ, which suggested that the PPARγ gene might have various effects on different tissues of pigeion, and also provide theoretical foundation for the further study of the structure and function of PPARγ.
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