Collagen, type VII, alpha 1

Collagen alpha-1(VII) chain is a protein that in humans is encoded by the COL7A1 gene.

Function

This gene encodes the alpha chain of type VII collagen. The type VII collagen fibril, composed of three identical alpha collagen chains, is restricted to the basement zone beneath stratified squamous epithelia. It functions as an anchoring fibril between the external epithelia and the underlying stroma. Mutations in this gene are associated with all forms of dystrophic epidermolysis bullosa. In the absence of mutations, however, an autoimmune response against type VII collagen can result in an acquired form of this disease called epidermolysis bullosa acquisita.

Type VII collagen is also found in the retina; its function in this organ is unknown.

COL7A1 is located on the short arm of human chromosome 3, in the chromosomal region denoted 3p21.31. The gene is approximately 31,000 base pairs in size and is remarkable for the extreme fragmentation of its coding sequence into 118 exons. COL7A1 is transcribed into an mRNA of 9,287 base pairs. In the skin, the type VII collagen protein is synthesized by keratinocytes and dermal fibroblasts.