Fig. 5.

NUR77 Is Recruited to the Proximal StAR Promoter

A, In vivo recruitment of NUR77 to the proximal mouse StAR promoter was determined by ChIP assays using MA-10 and rat primary Leydig cells. An aliquot (10%) of chromatin preparation before immunoprecipitation (input) was used as positive control. Chromatin was precipitated with a NUR77 antiserum (αNUR77, black bars) or a preimmune serum (IgG, white bars), which serves as negative control. A 258-bp fragment of the StAR promoter, encompassing the NBRE/SF-1 element, was amplified by real-time PCR. Results are presented as a ratio of StAR promoter-immunoprecipitated DNA to input DNA levels and are representative of three independent experiments. *, Statistically significant difference from the control. B, NUR77 phosphorylation is decreased in response to cAMP stimulation. MA-10 Leydig cells were treated with 0.5 mm (Bu)₂-cAMP as indicated. Nuclear extracts were prepared, separated by SDS-PAGE, transferred to PVDF membrane, and immunodetected using antisera specific for phosphorylated forms of NUR77 (Phospho S340 and Phospho S350) or total NUR77. All experiments were repeated three times and produced identical results.