FIG. 6.

RNase A/T₁ protection assay used to identify the collagen mRNA-suppressive element(s) in the first five exon/intron regions in various rodent fibroblast cell lines. (A) RNase protection assay using total RNA from Rat-1 and v-fos-transformed 1302-4-1 cells untransfected or transiently transfected with either pSTBB2.6 or pSTBB0.7. (B) RNase protection assay using total RNA from mouse NIH 3T3 fibroblasts untransfected or transiently transfected with the plasmids indicated. The α1(I) and rat GAPDH antisense riboprobes and the expected protected bands are described in the legends to Fig. 2 and 3. The 406-nt antisense mouse GAPDH riboprobe transcribed from pTRI-GAPDH-mouse protects a 316-nt mouse GAPDH mRNA fragment. (C) Determination of the number of copies of various plasmids transfected into different rodent cell lines shown in panels A and B, using quantitative PCR amplification of the amp gene and PhosphorImager analyses.