Procollagen alpha 2(I) mRNA in dermatosparactic fibroblasts: evidence for post-transcriptional regulation

Dermatosparaxis is a genetic defect of connective tissues found in man and animals. Dermatosparactic sheep fibroblasts fail to cleave off the aminopropeptide of procollagen, this makes the feedback regulation less effective and leads to an elevated production of collagen. We have isolated the total RNA from dermatosparactic and normal sheep fibroblasts and then compared the amount of mRNA sequences complementary to alpha 2(I) genomic DNA. Using methyl mercury gels, the Northern hybridization procedure and dotting hybridization, we were able to show that the levels of mRNA specific for alpha 2(I) collagen were only marginally different in both fibroblast strains. Furthermore, the amount of collagen mRNA translatable in a cell-free translation system was the same in affected and non-affected sheep cells. Our data provide further evidence for a post-transcriptional control of collagen synthesis in fibroblasts.