Cloning and expression of PPAR-gamma and PGC-1alpha from the hibernating ground squirrel, Spermophilus tridecemlineatus.
The peroxisome proliferator-activated receptor (PPAR) family of transcription factors play a key role in lipid metabolism and have been implicated in a number of disease states, most notably of which is obesity. Controlled regulation of lipid metabolism is a key ingredient for successful hibernation. Partial cDNA sequences for one of the PPAR proteins, PPARgamma and the PPARgamma co-activator (PGC-1alpha) have been cloned from the hibernating ground squirrel, Spermophilus tridecemlineatus and show differential regulation during hibernation at the mRNA level using relative RT-PCR and at the protein level via immunoblotting in brown adipose tissue (BAT), heart, skeletal muscle and white adipose tissue (WAT). The cDNA sequence for PGC-1alpha revealed a number of amino acid substitutions and two were worthy of note, one resulting in the loss of a potential protein kinase C (PKC) site, while another resulted in the creation of a PKC site, suggesting that PKC may be important in regulating PGC-1alpha. RT-PCR revealed a near 2-fold up-regulation of PPARgamma in BAT and to a lesser extent (<1.5-fold) in heart and WAT, while PGC-1alpha displayed significantly higher levels of expression in skeletal muscle during hibernation (3.1-fold, p < 0.005). The protein levels of PPARy were significantly increased in BAT and WAT (1.5 and 1.8-fold, respectively) while PGC-1alpha displayed significant changes in expression in heart (3.5-fold) and skeletal muscle (1.8-fold). Our current findings indicate a role for increased expression of PPARy and PGC-1alpha in hibernating animals.
Eddy
Sean F
SF
Institute of Biochemistry and Department of Chemistry, Carleton University, Ottawa, Canada. eddy@biochem.bumc.bu.edu
Morin
Pier
P
Storey
Kenneth B
KB
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D015870:Gene Expression; D006605:Hibernation / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D047495:PPAR gamma / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D012589:Sciuridae / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
D047495:PPAR gamma; D012333:RNA, Messenger; D014157:Transcription Factors; C111264:peroxisome-proliferator-activated receptor-gamma coactivator-1