FIG. 3.

(A) Inhibition of adipocytic differentiation induced by blockage of HMGI(Y) synthesis. Adipogenic differentiation of normal and pCMVneo- or pCMV-HMGI(Y)as-transfected 3T3-L1 cells is shown. Cell clones were cultured in the presence of standard differentiation induction medium containing 0.5 mM 1-methyl-3-isobutylxanthine, 1 mM dexamethasone, 5 μg of insulin/ml, and 10% fetal bovine serum. After 8 days of differentiation, cells were observed by light microscopy. Magnification, ×400. This experiment is representative of five independent assays. (B) mRNA levels of aP2 and leptin were determined by RT-PCR, gel electrophoresis, and Southern blot hybridization. For details, see Materials and Methods. The cDNAs were coamplified with GAPDH, as an internal control. No bands are seen in non-reverse-transcribed RNAs, thus excluding DNA contamination (data not shown). RNAs were extracted from these cells at days 0, 4, and 7 of differentiation, as indicated.