Fig. 3.

NUR77 Activates the StAR Promoter

A, Activation of the StAR promoter by NUR77. MA-10 Leydig cells (left panel) and Y-1 adrenal cells (right panel) were cotransfected with a −902- to +17-bp mouse StAR reporter construct along with either an empty expression vector (CTL; white bars) or expression vectors (250 ng) for NUR77 family members (NUR77, NURR1, and NOR-1; black bars), SF-1 (hatched bars), and LRH-1 (stippled bars) as indicated. The positions of the previously characterized binding sites for SF-1 within the −902- to +17-bp StAR promoter fragment (−890, −135, −95, and −42 bp) are represented by triangles. The number of experiments, each performed in duplicate, is indicated. Results are shown as fold activation over control (±sem). Activations statistically different from control are indicated by an asterisk. B, Localization of the Nur77-responsive element in the StARpromoter. To locate the NUR77-responsive element, MA-10 Leydig (left panel) and Y-1 adrenal (right panel) cells were cotransfected with various 5′ deletion constructs of the mouse StAR promoter (the 5′-end point of each construct is indicated on the left of the graph) with 250 ng of either an empty expression vector (white bars) or an expression vector for NUR77 (black bars). The number of experiments, each performed in duplicate, is indicated. Results are shown as fold activation over control (±sem).