Figure 7.

Id2 regulates the expression and activity of Hes1. A, Total RNA was collected from WT and Id2^−/− neural progenitor cells, reverse transcribed, and analyzed for Hes1 mRNA using RT-PCR. B, Western blot indicating that transient expression of Id2 using adenovirus results in increased expression of Hes1 protein. C, Luciferase reporter assays were conducted using firefly luciferase driven by the Hes1 promoter. Hes1 reporter activity was induced by cotransfection with constitutively activated Notch1. Addition of Id2 adenovirus resulted in increased activity of the reporter compared with the LacZ control virus. D, A representative experiment of real-time PCR analysis of Hes1 and Mash1 mRNA levels in cultured neural progenitor cells, from WT and Id2^−/− mice. E, Stable cell lines were created by infections with retroviral vectors expressing shRNA directed against the Hes1 or a control virus expressing shRNA directed against eGFP in cultured neural progenitor cells. Western blot indicates that Hes1 knock-down results in increased expression of Mash1.