TRANSCRIPTIONAL ACTIVATION OF TYPE-1 COLLAGEN GENES BY ASCORBIC-ACID 2-PHOSPHATE IN HUMAN SKIN FIBROBLASTS AND ITS FAILURE IN CELLS FROM A PATIENT WITH ALPHA(2)(I)-CHAIN-DEFECTIVE EHLERS-DANLOS SYNDROME

L-Ascorbic acid 2-phosphate (Asc 2-P), a long-acting vitamin C derivative, stimulated transcription of genes for proα1(I) and proα2(I) collagen in normal human skin fibroblasts after 8 h of treatment in the absence or in the presence of cycloheximide, indicating Asc 2-P stimulates transcription of type I collagen genes in the absence of protein synthesis. The transcriptional rate in these cells reached the maximum value after 40 h of treatment, and at that time it was three to four times higher than that of the control cells cultured in the absence of Asc 2-P. Steady-state levels of mRNAs for proα1(I) and proα2(I) chains were also increased to be three to four times higher than the control levels by treatment of the cells with Asc 2-P for 72 h. When the fibroblasts obtained from a patient with Ehlers-Danlos syndrome were treated with Asc 2-P, the derivative also stimulated transcription of the gene for proα1(I) chain and accumulation of mRNA for proα1(I) chain. On the other hand, Asc 2-P failed to stimulate transcription of the proα2(I) gene or an increase in mRNA for proα2(I) chain. Sodium ascorbate showed effects quite similar to those of Asc 2-P, when fibroblasts obtained from a normal control or the patient were cultured for 16 h with it. These results indicate the existence of cis-regulatory elements responsible for transcriptional activation by Asc 2-P or ascorbic acid in proα1(I) and proα2(I) genes of normal fibroblasts. These data also suggest some defect(s) of these elements in the proα2(I) gene of the patient with Ehlers-Danlos syndrome. © 1993 Academic Press, Inc.