Gene structure for the alpha 1 chain of a human short-chain collagen (type XIII) with alternatively spliced transcripts and translation termination codon at the 5' end of the last exon.

Publisher Website
Google Scholar
Abstract
Two overlapping human genomic clones that encode a short-chain collagen, designated .alpha.1(XIII), were isolated by using recently described cDNA clones. Characterization of the cosmid clones that span .apprxeq. 65,000 base pairs (bp) of the 3'' end of the gene established several unusual features of this collagen gene. The last exon encodes solely the 3'' untranslated region and it begins with a complete stop codon. The 10 adjacent exons vary in size from 27 to 87 bp and two of them are 54 bp. Therefore, the .alpha.1-chain gene of type XIII collagen has some features found in genes for fibrillar collagens but other features that are distinctly different. Previous analysis of overlapping cDNA clones and nuclease S1 mapping of mRNAs indicated one alternative splicing site causing a deletion of 36 bp from the mature mRNA. The present study showed that the 36 pb is contained within the gene as a single exon and also that the gene has a 45-bp -Gly-Xaa-Xaa- repeat coding exon not found in the cDNA clones previously characterized. Nuclease S1 mapping experiments indicated that this 45-bp exon is found in normal human skin fibroblast mRNAs. Accordingly, the data demonstrate that there is alternative splicing of at least two exons of the type .alpha.1(XIII)-chain gene.