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α1(VIII)‐collagen gene transcripts encode a short‐chain collagen polypeptide and are expressed by various epithelial, endothelial and mesenchymal cells in newborn mouse tissues

1992; Wiley; Volume: 207; Issue: 3 Linguagem: Inglês

10.1111/j.1432-1033.1992.tb17122.x

1432-1033

Yasuteru Muragaki, Chiyo Shiota, Masaya Inoue, Akira Ooshima, Bjørn R. Olsen, Yoshifumi Ninomiya,

Cancer-related gene regulation

Type‐VIII collagen is a major constituent of Descemet's membrane and contains two genetically distinct α chains, α1(VIII) and α2(VIII). We have previously cloned the human α1(VIII) and α2(VIII) genes and determined that they are located on chromosomes 3 and 1, respectively. Comparison of the α1(VIII) and α2(VIII) genes with the α1(X)‐collagen gene showed that the structure of the three genes and the sequence of their collagen polypeptides were strikingly similar. Therefore, we have grouped the three genes in a common subclass of collagens which we have named the short‐chain collagens because of the relatively small size of their triple‐helical domains. In the present study, we have isolated and characterized a mouse gene fragment encoding the entire mouse α1(VIII)‐collagen chain and determined the complete primary structure of the polypeptide chain. The size of mouse α1(VIII)‐collagen mRNA, as estimated by Northern‐blot analysis, was 4.2 kb, compared with 2.8 kb previously reported for the corresponding rabbit mRNA. By cloning and sequencing of four overlapping cDNA, we demonstrate that this larger size of mouse α1(VIII) mRNA is due to a larger 3′ untranslated region in the mouse transcript. Using the gene fragment as a probe, we performed Northern‐blot hybridization analysis of RNA prepared from newborn mice and demonstrated that α1(VIII) collagen mRNA is expressed at high levels in the calvarium, eye and skin. In situ hybridization revealed that α1(VIII) RNA is present in skin keratinocytes, corneal epithelial and endothelial cells, lens epithelial cells, as well as mesenchymal cells surrounding cartilage and calvarial bone and in the meninges surrounding the brain.