Structural organization of the human type VII collagen gene (COL7A1), composed of more exons than any previously characterized gene
- Univ. of Wisconsin, Madison, WI (United States)
- Thomas Jefferson Univ., Philadelphia, PA (United States)
The human type VII collagen (COL7A1) gene is the locus for mutations in at least some cases of dystrophic epidermolysis bullosa. Here the authors describe the entire intron/exon organization of COL7A1, which is shown to have 118 exons, more than any previously described gene. Despite this complexity, COL7A1 is compact. Consisting of 31,132 bp from transcription start site to polyadenylation site, it is only about three times the size of type VII collagen mRNA. Thus, COL7A1 introns are small. A 71-nucleotide COL7A1 intron is the smallest intron yet reported in a collagen gene, and only one COL7A1 intron is greater than 1 kb in length. All exons in the COL7A1 triple helix coding region that do not begin with sequences corresponding to imperfections of the triple helix begin with intact codons for Gly residues of Gly-X-Y repeats. This is reminiscent of the structure of fibrillar rather than other nonfibrillar collagen genes. In addition, the COL7A1 triple helix coding region contains many exons of recurring sizes (e.g., 25 exons are 36 bp, 12 exons are 45 bp, 8 exons are 63 bp), suggesting an evolutionary origin distinct from those of other nonfibrillar collagen genes. Sequences from the 5[prime] portion of COL7A1 are presented along with the 3766-bp intergenic sequence, which separated COL7A1 from the upstream gene encoding the core I protein of the cytochrome bc[sub 1] complex. The COL7A1 promoter region is found to lack extensive homologies with promoter regions of other genes expressed primarily in skin. 60 refs., 5 figs., 1 tab.
- OSTI ID:
- 6758360
- Journal Information:
- Genomics; (United States), Journal Name: Genomics; (United States) Vol. 21:1; ISSN 0888-7543; ISSN GNMCEP
- Country of Publication:
- United States
- Language:
- English
Similar Records
Compound heterozygosity for COL7A1 mutations in twins with dystrophic epidermolysis bullosa: A recessive paternal deletion/insertion mutation and a dominant negative maternal glycine substitution result in a severe phenotype
Human type VII collagen: cDNA cloning and chromosomal mapping of the gene