[Molecular cloning and analysing of porcine obese cDNA]

Obese gene (ob) is a novel gene cloned recently. The product of ob gene Leptin is an important signal reflecting body fat mass and controlling body weight. In this study the complete nucleotide sequences of porcine ob cDNA were identified, and the homology with ob genes from other species was also compared. The porcine fat cDNA was constructed based on lambda Uni-ZAP system. The primers designed on the consensus region of human and mouse ob gene were employed to perform PCR-screening of the cDNA library, and a 366 bp DNA fragment amplified from total RNA of pig fat cells was used to confirm positives as a hybridization probe. The complete ob cDNA with 3277 bp in length was cloned and sequenced. The nucleotide sequences of ob genes between different species were very conservative. The overall identity of ob nucleotide sequences was 88.5% between pig and human, 84.7% between pig and mouse. The homology of ob amino acid sequences was 86.0% between pig and human. 83.4% between pig and mouse. The result of RT-PCR for transcripts detection of pig ob gene indicate that ob gene was expressed not only mainly in adipose tissue but also slightly in other tissues such as kidney, liver, spleen, heart and muscle, which imply that expression nature of pig ob gene is different from that of human and mouse ob gene.