Fig. 2

Constitutively active Stat5A and Stat5B promote expression of proadipogenic factors. a Ectopic expression of constitutively active Stat5s induces proadipogenic transcription factors. 3T3-L1 cells were infected with control retrovirus vector (pLNCX2), vector harboring constitutively active Stat5A (Stat5A*) or Stat5B (Stat5B*). After G418 selection, cells were grown to confluence and subjected to the adipogenic regimen as described in the “Materials and methods” section. Total RNA was extracted at the indicated time, and 2 μg of each sample was subjected to Northern blot analysis with the antisense riboprobes corresponding to the genes. Three independent experiments were performed, and essentially identical results were obtained. b Induction of adipogenic marker genes in cells transduced with constitutively active Stat5s. Total RNA was isolated at 10 days post differentiation induction and subjected to Northern blot analysis with DIG-labeled riboprobes. Lane 1 cells transduced with the empty vector, lane 2 cells harboring Stat5A*, lane 3 cells harboring Stat5B*. c Increase of C/EBPα and PPARγ proteins upon Stat5 transduction. Cells harboring empty vector, Stat5A* or Stat5B* were subjected to the adipogenic regimen. Ten days later, cells were harvested and cell lysates were prepared. After separation on SDS gel, the proteins were visualized by the indicated antibodies using an ECL system. For Stat5, position of Stat5A and Stat5B is depicted by arrow. Lane 1 cells transduced with the empty vector, lanes 2 and 3 cells harboring Stat5A* or Stat5B*, respectively