Adaptation Of ATGL In Hibernation Of Bats

Hibernators eat large amounts of food and store body fats in pre-hibernation season, they enter hibernation with reduced metabolic rate, and mainly rely on energy produced by lipolysis to survive hibernation period. Adipose triglyceride lipase (ATGL) encoded by the ATGL gene is identified as a major lipase with triacylglyceride hydrolysis activity. It is a rate-limiting enzyme in lipolysis. To determine whether ATGL experience adaptive changes to hibernation in bats, we investigated the mRNA expression in bats that are capable of hibernation and the expression level of ATGL protein were compared between torpid and active sates of bats. We sequenced part of the ATGL coding region from several bat species, including 13 species of hibernating bats and 5 species of non-hibernating bats for the evolutionary analysis. Results of quantitative real-time PCR showed that ATGL mRNA expressed mainly in adipose tissues, but its expression level is relatively lower in other tissues, such as heart, kidney, spleen, pancreas, stomach and intestines. We found that the expression level of ATGL was significantly higher in torpid than in active bats. Results of molecular evolutionary analysis demonstrated that ATGL gene was conserved. In addition, the selective pressure acting on ATGL gene is different between hibernating bats and non-hibernating bats. Taken together, these data imply that ATGL is adaptive to hibernation in bats.