title: Adaptation of peroxisome proliferator-activated receptor alpha to hibernation in bats.
abstract: BACKGROUND
  Hibernation is a survival mechanism in the winter for some animals. Fat preserved instead of glucose produced is the primary fuel during winter hibernation of mammals. Many genes involved in lipid metabolism are regulated by the peroxisome proliferator-activated receptor alpha (PPARα). The role of PPARα in hibernation of mammals remains largely unknown. Using a multidisciplinary approach, we investigated whether PPARα is adapted to hibernation in bats.
  
  
  RESULTS
  Evolutionary analyses revealed that the ω value of Pparα of the ancestral lineage of hibernating bats in both Yinpterochiroptera and Yangochiroptera was lower than that of non-hibernating bats in Yinpterochiroptera, suggesting that a higher selective pressure acts on Pparα in hibernating bats. PPARα expression was found to be increased at both mRNA and protein levels in distantly related bats (Rhinolophus ferrumequinum and Hipposideros armiger in Yinpterochiroptera and Myotis ricketti in Yangochiroptera) during their torpid episodes. Transcription factors such as FOXL1, NFYA, NFYB, SP1, TBP, and ERG were bioinformatically determined to have a higher binding affinity to the potential regulatory regions of Pparα in hibernating than in non-hibernating mammals. Genome-wide bioinformatic analyses of 64 mammalian species showed that PPARα has more potential target genes and higher binding affinity to these genes in hibernating than in non-hibernating mammals.
  
  
  CONCLUSIONS
  We conclude that PPARα is adapted to hibernation in bats based on the observations that Pparα has a more stringent functional constraint in the ancestral lineage of hibernating bats and a higher level of expression in hibernating than in non-hibernating bats. We also conclude that PPARα plays a very important role in hibernation as hibernators have more PPARα target genes than non-hibernators, and PPARα in hibernators has a higher binding affinity for its target genes than in non-hibernators.
authors.affiliation: Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, 200062, China. yijiehan@gmail.com.
authors.forename: Yijie
authors.initials: Y
authors.lastname: Han
authors.affiliation: Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, 200062, China. guantao.zheng@gmail.com.
authors.forename: Guantao
authors.initials: G
authors.lastname: Zheng
authors.affiliation: Laboratory of Molecular Ecology and Evolution, Institute for Advanced Studies in Multidisciplinary Science and Technology, East China Normal University, Shanghai, 200062, China. ytxiao1226@hotmail.com.
authors.forename: Tianxiao
authors.initials: T
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China. syzhang@bio.ecnu.edu.cn.
authors.forename: Shuyi
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Laboratory of Molecular Ecology and Evolution, Institute of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China. ddong.ecnu@gmail.com.
authors.forename: Dong
authors.initials: D
authors.lastname: Dong
authors.affiliation: Laboratory of Molecular Ecology and Evolution, Institute of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China. yihsuanp@gmail.com.
authors.forename: Yi-Hsuan
authors.initials: YH
authors.lastname: Pan
mesh_terms: D000064:Acclimatization; D000222:Adaptation, Physiological; D000818:Animals; D002685:Chiroptera / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D006605:Hibernation; D047493:PPAR alpha / Q000737:chemistry / Q000235:genetics*; D012621:Seasons; D012641:Selection, Genetic
chemical_list: D047493:PPAR alpha