Figure 2. R-roscovitine inhibition of rPomc promotor activity and corticotroph transcriptional factors.

A, Luciferase assay was performed using rat POMC gene proximal promoter constructs in AtT20 cells treated with or without R-roscovitine under indicated concentrations. B, Luciferase assay of rat Pomc gene promoter construct with Tpit and Pitx1 binding sites mutation in AtT20 cells treated with or without R-roscovitine under the indicated concentrations. Left panel, DNA sequence of the Tpit/Pitx1 binding site is shown. Tpit and Pitx1 sites are indicated in bold. Mutations are indicated by italic capital letters for Tpit and Pitx1 binding sites. C, Western blot of protein extract derived from AtT20 cells treated with vehicle or R-roscovitine. Data shown are representative results from at least two independent experiments.