Identification and characterization of a novel mouse peroxisome proliferator-activated receptor a-regulated and starvation-induced gene, Ppsig

The peroxisome proliferator-activated receptor alpha (PPARa) has been known to play a pivotal role in maintaining the energy balance during fasting; however, the battery of PPARa target genes involved in this metabolic response is still not fully characterized. Here, we report the identification and characterization of Ppsig (for PPARa-regulated and starvation-induced gene) with unknown biological function from mouse liver. Multiple Ppsig cDNAs which differed in the 3'-untranslated regions were identified. The open reading frame of Ppsig cDNA is 1830 bp which encodes a protein of 67.33 kDa. Ppsig contains 11 exons spanning at least 10 kb. Although the exact biological function of Ppsig is still not known, we found that Ppsig mRNA transcript was dramatically up-regulated during 72 h fasting and following treatment with a potent PPARa agonist, in a tissue-specific and PPARa-dependent manner. A functional peroxisome proliferator-response element was found in the intron 1 of Ppsig, thus confirming that Ppsig is a novel direct mouse PPARa target gene. This finding might help in elucidating the transcriptional regulatory mechanism of Ppsig in the cellular response to fasting.