Molecular characterization and expression analysis of fat mass and obesity-associated gene in rabbit

Fat mass and obesity-associated (FTO) gene codes for a nuclear protein of the AlkB related nonhaem iron and 2-oxoglutaratedependent oxygenase superfamily, and is involved in animal fat deposition and human obesity. In this work, the molecular characterization and expression features of rabbit (Oryctolagus cuniculus) FTO cDNA were analysed. The rabbit FTO cDNA with a size of 2158 bp was cloned, including 1515 bp of the open reading frame that encoded a basic protein of 504 amino acids. Homologous comparison indicated that the rabbit FTO shared 36.36-91.88% identity with those from other species and phylogenetic analysis showed that the rabbit FTO is closely related to human, but more distantly related to zebrafish. The New Zealand rabbit FTO mRNA was detected in all tissues examined, with the highest levels found in the spleen and the lowest found in the kidney. However, no significant differences were seen in cerebellum, corpora quadrigemina, medulla oblongata and cerebral cortex of commercial adult rabbits. Moreover, mRNA levels of FTO in liver tissues were significantly increased in lactating New Zealand rabbits compared with 70-day-old, 90-day-old and gestating rabbits (P < 0.05). In contrast, FTO mRNA levels were significantly lower in longissimus dorsi muscle of 90-day-old New Zealand rabbits than in 70-day-old rabbits (P <0.05). However, the expression levels of FTO in mammary gland and ovary of gestating and lactating rabbits were not significantly different (P > 0.05).