FIG. 1.

(A) HMGI(Y) induction during NIH 3T3-L1 preadipocyte differentiation. Total RNA (20 μg/lane) extracted from proliferating and differentiated 3T3-L1 cells was hybridized with the HMGI(Y) cDNA and then with a rat GAPDH probe as a control for RNA loading. RNA was extracted from undifferentiated proliferating cells (P) at time zero and at 6 h, 1 day, and 4 days of differentiation, as indicated. (B) Nuclear proteins extracted from normal and induced 3T3-L1 cells were separated (20 μg/lane) by SDS-PAGE and transferred to polyvinylidene difluoride membranes. Western blots were incubated first with antibodies specific for HMGI(Y) proteins and then with horseradish peroxidase-conjugated secondary antibodies; the immunocomplexes were detected by enhanced chemiluminescence. As a control for equal loading, the blotted proteins were stained with Ponceau Red. Moreover, the same Western blots were incubated with antibodies to the ubiquitous γ-tubulin protein. Proteins were extracted from the same cells as in panel A.