Human α1(III) and α2(V) procollagen genes are located on the long arm of chromosome 2

The multigene procollagen family encodes probably >20 genetically distinct but structurally related polypeptide chains. Recent characterization of human procollagen clones has allowed determination of functional domains within the proteins, genomic organization, and chromosomal location. Previously, we assigned the coordinately expressed type I genes (α1 and α2) to chromosomes 17 and 7, respectively, and now other investigators have mapped the type II gene to chromosome 12. Recently, we isolated cDNA clones encoding the fourth interstitial procollagen, type III, and the α2 chain of the type V cytoskeletal components. To determine whether these genes were clustered with α1(I), α2(I), or α1(II) or were further dispersed in the genome, in situ hybridization of the α1(III) and α2(V) probes to metaphase chromosomes was carried out. Here we report a fourth autosome with procollagen gene loci but the first cytological evidence for linkage. By using normal and translocated cell lines, our results show that both the α1(III) and α2(V) procollagen genes map to the q24.3→q31 region of chromosome 2.