Characterization and Functional Assessment of Mouse PPARγ1 Promoter

Background: peroxisome proliferator activated receptor gamma (pparγ), a member of nuclear receptor superfamily, comprises two isoforms in mouse. these two isoforms are encoded by different mrnas, which are arisen by al- ternative promoter usage. there are two promoter regions upstream of pparγ gene. a 3 kb fragment, containing several transcription factor binding sites, acts as pparã1 promoter region. thus, expression pattern of pparγ1 iso- form is due to the potential transcription factors that could influence its pro- moter activity. pparγ, retinoid x receptor (rxr) and vitamin d receptor (vdr), as nuclear receptors could influence pparã gene expression pattern during several differentiation processes. during neural differentiation, pparã1 isoform expression reaches to maximal level at neural precursor cell formation. methods: a vast computational analysis was carried out to reveal the pparγ1 promoter region. the putative promoter region was then subcloned upstream of an egfp reporter gene. then the functionality of pparγ1 promoter was as- sessed in different cell lines. results: results indicated that rosiglitazone increased pparã1 promoter regu- lated egfp expression of neural precursor cells during embryoid body (eb) formation. furthermore vitamin d reduced pparγ1 promoter regulated egfp expression of neural precursor cells during eb formation through bind- ing to its receptor. conclusion: this study suggests that there are potential response elements for ppar/rxr and vdr/rxr heterodimers in pparã1 isoform promoter. also vdr/rxr heterodimers may decrease pparγ expression through binding to its promoter.