Interaction of the locust FABP promoter with RXR

The expression of the fatty acid binding protein (FABP) in locust flight muscle is up-regulated by fatty acids via a fatty acid response element in the promoter of its gene that binds to unknown nuclear receptor proteins. In this study, the involvement of the retinoid-X receptor was studied. A cDNA library of Schistocerca gregaria flight muscle was constructed, and two RXR isoforms were cloned. Yeast one-hybrid interaction screens were used to assess the interaction between the FABP fatty acid response element and RXR. Vectors expressing RXR/GAL4-activation domain fusion proteins were constructed using yeast homologous recombination. RXR/GAL4 transcriptional activation was then tested using vectors containing the wild-type and altered fatty acid response element sequences. These experiments demonstrated that both RXR isoforms interact with the element, suggesting RXR involvement. Further research is needed to reveal the molecular mechanism of FABP gene regulation.