Head-to-head arrangement of murine type IV collagen genes.

P Kaytes,L Wood,N Theriault,M Kurkinen,G Vogeli

doi:10.1016/s0021-9258(19)77629-7

Abstract

The genes for the two dissimilar subunits of type IV collagen are organized in a head-to-head manner with their translation initiation codons within 874 base pairs. Murine genomic clones which contain portions of both genes have been isolated and characterized. These clones contain the first exon of the alpha 1(IV) chain and the first 3 exons for the alpha 2(IV) chain within a 1.7-kilobase HindIII fragment. The intergenic region appears not to resemble previously described bidirectional promoters. The HindIII fragment is present as a single copy in the mouse genome ruling out the presence of one of these gene fragments as a pseudogene. These findings agree with linkage studies of these two genes and differ from the known organization of human fibrillar collagen genes which have been found to be dispersed within the human genome.

Highlights

From $MolecularBiology Research and §Biopolymer Chemistry, The Upjohn Company, Kalumazoo, Michigan 49007 and the YDepartment of Biochemistry, University of Medicine and Dentistry of New Jersey, Rutgers Medical School, Piscataway, New Jersey 08854
Type IV collagen is of particular interest since it forms the scaffold of an essential histological and physiological structure known as the basement membrane (Timpl et al, 1981; Yurchenco and Furthmayer, 1984)and theregulation of its expression is under developmental control (Marotti et al, 1985; Kleinman et al, 1987).Type IV collagen is a trimeric molecule composed of two genetically distinct chains, two of the a1 type and one a2 (Alitalo et al, 1980; Tryggvason et al, 1980)
We have previously described cDNA clones for both chains andshown that these two chains arose by the process of gene duplication (Vogeli et al, 1986; Kaytes et al, 1987; Woodet al., 1988).In contrast to past reports in which related fibrillar collagen geneswere found to be dispersed throughout the human genome (Solomon et al, 1985; reviewedin Myers and Emanuel, 1987), type IV collagen shows tight linkage between the human genes for the two subunits of this protein

Summary

Introduction

From $MolecularBiology Research and §Biopolymer Chemistry, The Upjohn Company, Kalumazoo, Michigan 49007 and the YDepartment of Biochemistry, University of Medicine and Dentistry of New Jersey, Rutgers Medical School, Piscataway, New Jersey 08854. We have previously described cDNA clones for both chains andshown that these two chains arose by the process of gene duplication (Vogeli et al, 1986; Kaytes et al, 1987; Woodet al., 1988).In contrast to past reports in which related fibrillar collagen geneswere found to be dispersed throughout the human genome (Solomon et al, 1985; reviewedin Myers and Emanuel, 1987), type IV collagen shows tight linkage between the human genes for the two subunits of this protein

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