Tissue-specific expression and long-term deposition of human collagen VII in the skin of transgenic mice: implications for gene therapy

We report the isolation of a cosmid clone containing the entire human COL7A 1 gene in one piece. The ability of the genomic sequences within this clone to direct tissue-specific expression of human collagen VII in transgenic m ice was tested The data show that the gene construct is capable of directin g expression of collagen VII in the skin of fetal and neonatal transgenic m ice. Expression of COL7A1 in these mice was widespread, in a pattern consis tent with that found in human tissues and was in parallel with that of the endogenous mouse gene. Immunostaining, using human-specific antibodies show ed that human collagen VII protein was present at the skin basement membran e zone of the transgenic mice. Dermal extracts from 19-month-old transgenic mice contained mature human collagen VII protein, and fibroblasts derived from skin biopsies of these mice actively synthesized human collagen VII. T he demonstration of successful and stable expression of human collagen VII in in vivo gene transfer is the first step towards the future development o f therapeutic protocols for the rescue of keratinocyte function in severe b listering diseases such as dystrophic epidermolysis bullosa.