Gene mapping of human ocular connective tissue proteins. Assignment of the structural gene for corneal type I procollagen to human chromosome 7 in human corneal stroma-mouse fibroblast somatic cell hybrids.

Somatic cell hybrids between mouse and human corneal stroma fibroblasts have been used to identify the human chromosome responsible for the synthesis of human corneal type I procollagen. Twenty-six separate hybrid clones and subclones from three separate hybridization events were isolated in hypoxanthine-aminopterin-thymidine (HAT) selection medium and were used to assay for the production of human type I procollagen. Human and mouse chromosomes were identified in each hybrid clone by alkaline Giemsa staining of metaphase chromosomes spread and by isozyme analysis. We have found that human type I procollagen production segregates concordantly with human chromosome 7 and with beta-glucuronidase, another human chromosome 7 marker. The pro-alpha 1 gene and possibly the pro-alpha 2 gene appear to be encoded on human chromosome 7. Because we have previously assigned the gene for human skin type I procollagen to chromosome 17, our present data indicate that separate genes and control mechanisms must exist for skin and corneal type I procollagen.