Genetics of the connective tissue proteins: assignment of the gene for human type I procollagen to chromosome 17 by analysis of cell hybrids and microcell hybrids

Abstract

Somatic cell hybrids between mouse and human cell lines have been used to identify the specific chromosome that governs the synthesis of type I procollagen. Fourteen hybrid clones and subclones were derived independently from crosses between mouse parents [LM (thymidine kinase-negative) or A9 (hypoxanthine phosphoribosyltransferase-negative)] and human cells (human diploid lung fibroblasts WI-38 or diploid skin fibroblasts GM5, GM17, and GM9). The cultures were labeled with [(3)H]proline in modified Eagle's medium without serum. Radioactive procollagens were purified from the medium by the method of Church et al. [(1974) J. Mol. Biol. 86, 785-799]. DEAE-cellulose chromatography was used to separate collagen and type I and type III procollagen. Human type I procollagen was assayed by double immunodiffusion analysis with type I procollagen antibodies prepared by immunizing rabbits with purified human type I procollagen. These analyses combined with karyology and isozyme analyses of each hybrid line have produced evidence for the assignment of the gene for human type I procollagen to chromosome 17. A human microcell-mouse hybrid cell line containing only human chromosome 17 was positive for human type I procollagen, lending further support to the assignment of the human type I procollagen gene to chromosome 17. Finally, by using a hybrid line containing only the long arm of human chromosome 17 translocated onto a mouse chromosome, the type I procollagen gene can be assigned more specifically to the long arm of chromosome 17.