FIGURE 8.

Three class II HDACs are expressed in preadipocytes and can specifically regulate GLUT4 promoter activity in vitro. A, 120 μg of nuclear extracts of 3T3-L1 preadipocytes or adipocytes 6 days after differentiation were analyzed by SDS-PAGE and immunoblotted (IB) for endogenous HDAC4, HDAC5, or HDAC9 as indicated. Both the full-length protein and the lower splice variant were detected for all HDACs, but as the cells differentiated, the nuclear HDAC levels severely diminished. B, 3T3-L1 adipocytes 6 days after differentiation were transiently transfected with luciferase reporter plasmids −895-hG4-luc (firefly luciferase, for promoter activity) and pRLTK (Renilla luciferase, for transfection efficiency), with and without plasmids encoding GEF, MEF2A, wild type human HDAC4 (hHDAC4), wild type human HDAC5 (hHDAC5), or wild type human HDAC9 (hHDAC9). +, inclusion in transfection. The means ± S.E. from three independent experiments are shown; the data were analyzed by a one-way analysis of co-variance, and statistically significant (p < 0.005) changes are indicated.