Human type I procollagen genes are located on different chromosomes.

Abstract

A recombinant plasmid containing sequences complementary to human pro-al(I) collagen mRNA was used for the chromosomal assignment of the pro-al(I) collagen gene. Restriction endonuclease analysis of DNA from mouse-human and Chinese hamster-human somatic cell hybrids revealed cosegregation with human chromosome 17. Hybrids containing derivative chromosomes with a t(2;17Xql4;q2l) translocation showed cosegregation ofthe pro-al(I) gene with the segment 17q21+qter. In situ hybridization on human metaphasic chromosomes confirmed this conclusion.At least five genetically distinct collagen types have been identified in mammals. Of these, type I collagen is the most abundant; it is the major constituent of bone, tendon, skin, and fibroblasts. It consists of two al(I) chains and one a2(I) chain, which are synthesized as precursor polypeptides containing NH2-and COOH-terminal propeptides and called pro-al(I) and pro-a2(I) chains (1,2).The availability of genomic libraries has permitted the isolation of the entire chicken pro-a2(I) gene (3-7) and part of the sheep pro-a2(I) (8) and of the mouse pro-al(I) genes (9). More recently, we have reported the isolation of specific cDNAs and genomic fragments for the human pro-a2(I) and pro-al(I) chains (10-13). However, one major question remains: Are the genes coding for the nine (or more) different polypeptide collagen chains dispersed in the genome or clustered as one or several gene family(ies)? Conflicting results have been obtained when immunological techniques were used to determine the chromosomal location ofthe pro-al(I) and pro-a2(I) genes (4, 5). We have used the more direct approach ofrestriction endonuclease analysis of DNA from human-rodent somatic cell hybrids hybridized to labeled cloned cDNAs. Using this method, we have unequivocally assigned the gene coding for pro-a2(I) collagen chain (COLIA2) to human chromosome 7 (14). In the present paper we report the assignment of the gene coding for the proal(I) chain (COLIAl) hybrids, or the parental cells were fused with polyethylene glycol (16) and hybrid cells were selected in ouabain/hypoxanthine/aminopterin/thymidine medium (17) for the other hybrids. For counter-selection, hybrid cells L-53 were grown in standard medium supplemented with 5-bromodeoxyuridine (18). Cell lines were established and maintained as described (18)(19)(20). Cell hybrids were characterized by isozyme and karyotype analysis. Chromosomes were identified by R-banding (21).Recombinant Clones and DNA Analysis. From a human fibroblast cDNA library five overlapping clones specific for the pro-al(I) chain were isolated (12). The clones were characterized by restriction endonuclease mapping and direct DNA sequence analysis was performed according to Maxam and Gilbert (22). Here we have used one of these clones (Hf-677). Nuclear DNA purification and restriction endonuclease analysis were performed as described (14).In Situ Hybridization on Metaphase Chromosomes. A phytohemagglutinin-stimulated culture ofwhole blood from a normal woman was ...

Construction of a genetic map of human chromosome 17 by use of chromosome-mediated gene transfer.

“…In situ hybridization confirms the localization of HOX2 to 17q21-*q22 (43), and COLIA) has been previously mapped to 17q21-*q22 (44). It therefore appears that this second group is located in the region 17q21-+q22, most probably in the order cen-HOX2-(NGFR-COLIAI-MPO)-qter.…”

Immune interferon inhibits collagen synthesis by rheumatoid synovial cells associated wth decreaded levels of the procollagen mRNAs(FEBS 2156)

“…We do not yet know whether these decreases are accounted for by inhibition of transcription of the procollagen genes, altered processing of the transcript, altered transport from nucleus to cytoplasm or altered stability of the processed transcript [27]. If the decreased levels of these mRNAs do mvolve a decrease m transcription, then this effect has to be expressed at several different loci, since the human genes for the al(I) and &2(I) procollagens are located on different chromosomes, 17 and 7, respectively [28,29]. By analogy, in other conditions in which the levels of procollagen mRNAs are suppressed parallel to suppression of collagen protein synthesis, such as infection with Rous sarcoma virus, the effect is probably exerted at the level of transcription [30,31].…”

Number and organization of collagen genes in Caenorhabditis elegans.

“…personal communication). (19,25). A dispersed genome organization may be beneficial for collagen genes, which are internally repetitive, to reduce the incidence of homologous unequal recombination and to allow sequence diversity to be maintained.…”

“…Introns occur at a high frequency within the triple helix-coding regions of the genes, creating exons that typically are a multiple of 54 base pairs or six Gly-X-Y repeats (36). In humans, the type I al and (t2 collagen genes have been localized to different chromosomes (19).In contrast to the large amount of information available on vertebrate collagens, little is known of the number, primary sequences, or genomic organization of invertebrate collagens (1). The fruit fly, Drosophila melanogaster, apparently has two unlinked collagen genes that code for large proteins comparable in size to vertebrate collagens (25).…”

“…Introns occur at a high frequency within the triple helix-coding regions of the genes, creating exons that typically are a multiple of 54 base pairs or six Gly-X-Y repeats (36). In humans, the type I al and (t2 collagen genes have been localized to different chromosomes (19).…”