Related Experiment Video
Updated: Sep 20, 2026

Prediction and Validation of Gene Regulatory Elements Activated During Retinoic Acid Induced Embryonic Stem Cell Differentiation
Published on: June 21, 2016
Peroxisome proliferator-activated receptor alpha induces rat sterol carrier protein x promoter activity through two
Dayami Lopez1, Rosalyn B Irby, Mark P McLean
1Department of Obstetrics and Gynecology, University of South Florida, College of Medicine, Tampa, FL 33606, USA.
Abstract:
Sterol carrier protein x (SCPx) plays a critical role in the peroxisomal oxidation of fatty acids. It has been previously demonstrated in streptozotocin-induced diabetic rats that SCPx expression is induced in association with an elevation in serum fatty acid and triglyceride levels. To elucidate the mechanisms underlying the expression of this gene during diabetes, the rat SCPx promoter was cloned and analyzed for regulatory motifs. Sequence analysis of this TATA-less promoter revealed two putative peroxisomal-proliferator-response element (PPRE) binding motifs at positions -134 and -869 relative to the translation start site. To examine peroxisomal-proliferator-activated receptor alpha (PPARalpha) effects on this gene, 935 bp of the SCPx promoter containing both PPRE motifs was cloned in front of the chloramphenicol acetyl-transferase gene or the luciferase gene and co-transfected into HTB-9 cells with vectors that encoded for PPARalpha and retinoid X receptor (RXR). The results indicate that PPARalpha was able to induce SCPx promoter activity in both cases, an effect that was enhanced by RXR and clofibrate. In addition, mutational analysis studies demonstrated that both PPREs contributed to the PPARalpha/RXRalpha-dependent activation of the SCPx promoter. Mobility shift assays and supershift analysis showed that nuclear extracts containing PPARalpha bound to the two PPRE motifs. This investigation indicates that similar to other genes involved in beta-oxidation, SCPx transcription may be controlled by fatty acid levels via PPARalpha.
Related Concept Videos
Transducer Mechanism: Nuclear Receptors
About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes:
Protein Import into the Peroxisomes
Peroxisomal Protein Import:
Peroxisomes lack the genetic machinery required to code for their own proteins. Hence, most peroxisomal membrane, lumenal and transmembrane proteins are synthesized in the cytoplasm or ER and transported to the peroxisome...
Regulation of Nuclear Protein Sorting
Peroxisomes
Regulation of the Unfolded Protein Response
TGF - β Signaling Pathway