Transcription activity in fibroblasts from the adult tight skin (TSK) mouse

To assess if adult tight-skin mouse (TSK) skin fibroblasts have a parallel increase in transcription of collagen and non-collagen genes.

One-year-old TSK/+ and +/+ (normal littermate) dermal fibroblasts were transfected (lipotransfection) with plasmid constructs containing Chloramphenicol Acetyl Transferse (CAT) gene, directed by promoters of mouse alpha1(I) alpha2(I) and alpha1(III) collagen genes, and by viral enhancers of Simian virus 40, Rous sarcoma virus and an LTR from a Syrian hamster tumour retrovirus. Syrian hamster derived tumour cell lines MF2B and GRI, and fibroblast cell line 3T3/NIH were used as controls. In some experiments, transfected cells were treated with hormones as transcription activating factors. Mixing experiments of tumour cells and TSK/+ or +/+ fibroblasts were done to study potential inhibitors.

Collagen genes promoters failed to induce transcriptional activity in TSK/+ or +/+ fibroblasts, even in the presence of hormone treatment. Mixing experiments did not reveal inhibitor factors acting in these fibroblasts. Viral enhancers induced 2 to 5 times more transcription activity in TSK/+ than in +/+ fibroblasts.

Increased transcription of viral enhancers and not of collagen genes in adult TSK fibroblasts, suggests the presence of transcription activating factors independent of collagen gene activation.