FIG. 2.

RNase protection assays showing endogenous pro-α1(I) collagen mRNA levels in Rat-1, v-fos-transformed 1302-4-1, and revertant EMS-1-19 cells, untransfected or transiently transfected with pWTC1. The 850-nt antisense riboprobes transcribed by T7 RNA polymerase from a mouse pro-α1(I) collagen fragment (HindIII/EcoRI) of pSTBB0.7 were hybridized with total RNA extracted from equal number of cultured cells (about 10⁶), either untransfected or transfected by pWTC1 and harvested at 24 (A) and 48 (B) h after electroporation. Endogenous rat collagen mRNA protects a 194-nt major band (shown by the arrow) and some smaller minor bands of mouse α1(I) probe after treatment with RNase 1. Mouse α1(I) transcripts from pWTC1 are expected to protect 118- and 76-nt bands. PhosphorImager units corresponding to the protected major bands of endogenous α1(I) mRNA are indicated. This RNase protection experiment is representative of four separate assays with similar results.