Isolation of cDNAs encoding the complete sequence of bovine type X collagen. Evidence for the condensed nature of mammalian type X collagen genes

Abstract

The complete primary structure of the bovine alpha 1(X) collagen chain was determined by nucleotide sequencing of cDNA clones. The overlapping cDNA clones encode 3144 bp with a 5'-terminal untranslated region of 148 bp, a 2025 bp reading frame and a 3'-terminal untranslated region of 971 bp. This represents the first complete sequence of a mammalian type X collagen cDNA and has allowed a number of informative comparisons to be made with the previously published chick alpha 1(X) sequence. The primary translation products of both bovine and chick type X collagen are 674 amino acid residues in length and there is a 73.3% identity at the amino acid level (67.8% at the base level). Sequence analyses reveal that the greatest degree of identity between the two species occurs within the triple-helical domain and the C-terminal non-collagenous domain, whereas the identity within the N-terminal non-collagenous domain is markedly lower. The interchain disulphide-bonding observed previously within the triple helix of bovine type X collagen is explained by the presence of two cysteine residues within an imperfection of the triple-helical domain encoded by -Gly-Xaa-Cys-Xaa-Yaa-Cys-Xaa-Yaa-Gly-. Southern blot analyses of bovine genomic DNA demonstrate that the bovine type X collagen gene is likely to have a condensed structure, similar to that of the chick, with at least 1.3 kb of the coding sequence being contained within one exon.

Folding and Assembly of Type X Collagen Mutants That Cause Metaphyseal Chondrodysplasia-type Schmid

“…The overall domain structure of type X collagen is similar to the fibrillar procollagens in that there are three distinct domains: a short amino-terminal domain (NC2) 1 of 38 amino acids, a collagenous triple helical domain of 463 amino acids, and a non-collagenous carboxylterminal (NC1) domain of 161 amino acids (2). However, unlike the fibrillar procollagens, the propeptides are not cleaved following secretion into the extracellular matrix and are thought to play a role in assembly of the individual molecules into higher order structures (3).…”

Cloning of the human and mouse type X collagen genes and mapping of the mouse type X collagen gene to chromosome 10

“…2). The nucleotide sequence of the open reading frame was highly similar to the bovine al(X) sequence [17] at both the nucleotide level (85.9%) and at the level of the conceptual translation product ( Table 1). In addition, the conceptual translation product of 120 130 140 150 160 170 CCC TCA GCA CCG CCA CGC AAG CCA GGC TAT GGA AGT CCT GGA CTC CAA GGA GAG CCA P …”

“…Five imperfections were of the Gly-XaaGly type and three were of the Gly-Xaa-Yaa-Xaa-Yaa-Gly type. Although the translation product of the bovine cDNA also contains the same number of imperfections in the same relative positions [17], the fourth imperfection (from the Nterminal of the COL domain) codes for the sequence Gly-HisCys-Thr-Pro-Cys-Arg-Pro-Gly; the corresponding sequence in the chicken, human and mouse genes is Gly-Xaa-Gly. The cysteinyl residues within the bovine imperfections explain the disulfide bonding of the bovine type X homotrimer.…”

“…Although the chicken type X collagen gene [6, 71 and bovine cDNAs [17] encoding type X collagen have been isolated, the lack of the corresponding human and mouse genes is particularly unfortunate, as studies of the type X collagen gene and its product are likely to be much more informative in humans and mice. In both humans and mice there are a large number of chondrodysplasias, phenotypically distinct genetic disorders which result in abnormal cartilage structure and function.…”

Fell–Muir Lecture: From collagen chemistry towards cell therapy – a personal journey

“…We were fortunate that the rabbit anti-chick type X collagen cross-reacted with bovine type X collagen in spite of the fact that we found bovine type X collagen a-chains to possess interchain disulphide bonds within the helical segment, whereas chick collagen X had no such interchain linkages (Ayad et al 1987). These antibodies were to be critical in immunoscreening a cDNA expression library prepared from polyA + RNA isolated by oligo(dT)-cellulose affinity chromatography from extracts of cultured fetal bovine chondrocytes exhibiting maximal synthesis of type X collagen (Thomas et al 1991a). …”