Figure 6.

Proteins of the MAX network can regulate the expression of UBF. (A) Cultures of pBabe and pBabe-MYC-ER NIH3T3 cells were incubated in DMEM containing low serum and then stimulated with 4-OHT for 3–24 h before being analyzed for UBF mRNA expression by Northern blot (GAPDH control). UBF expression at each time point was quantitated by qRT-PCR analysis (normalized to GAPDH expression). The same cells were also analyzed by Western blot for UBF protein expression (α-tubulin control) and UBF levels were quantitated from at least four independent Western blots/experiments and represented as fold increase in MYC-ER cells over pBabe cells for each time point. (B) Proliferating NIH3T3 cells were infected with the pBabe or pBabe-MAD1 retrovirus, selected and analyzed by Western blot for expression of UBF (α-tubulin control).