Figure 4.

 Analysis of steady state mRNA levels by northern blot hybridisation. Confluent monolayer cultures of two systemic sclerosis dermal fibroblast cell lines were treated with various concentrations of mithramycin and total RNA extracted from the cultures was examined by northern hybridisation with cDNA for COL1A1 and GAPDH as described in "Materials and methods". Inset: northern analysis of cell line 1. Bar graph: open circles, cell line 1; closed circles, cell line 2. Mithramycin (50 nmol/l) decreased the steady state mRNA level of α1(I) by 40–60%.