FIG. 2.

Suppression of endogenous c-myc and pdgf-βr mRNA levels in rodent cells constitutively expressing exogenous c-Myc or v-Myc. (A) Total RNA (10 μg) from subconfluent primary control REF or REF infected with retrovirus carrying either the v-myc or human c-myc gene was analyzed by the RNase protection assay to detect endogenous rat c-myc (top panel), pdgf-βr (middle panel), and gapdh (bottom panel) mRNA levels. (B and C) RNA (10 μg) from subconfluent primary REF or rodent fibroblast cell lines (KPREF and Rat-1) infected with a control retrovirus (−) or retrovirus carrying the v-myc gene (+) was analyzed by the RNase protection assay to detect the presence of endogenous pdgf-βr and control gapdh genes (B) and endogenous rat c-myc, ectopic v-myc, and control gapdh genes (C).