Abstract
We have isolated cDNA clones that code for a proteoglycan-related polypeptide with unique properties. A lambda gt11 expression library made from human fibroblast mRNA was screened with an antiserum made against a proteoglycan fraction from human fetal membranes. One group of positive clones revealed an open reading frame coding for 685 amino acids from the COOH terminus of a polypeptide. This amino acid sequence contains a domain that is strongly homologous with the COOH-terminal core protein domain of the large aggregating cartilage proteoglycan. This domain also contains sequences that are homologous with vertebrate lectins that bind terminal galactosyl, N-acetyl-glucosaminyl or mannosyl residues. On the NH2-terminal side of the lectin-like domain the cDNA-derived amino acid sequence contains two epidermal growth factor-related segments. The cDNA clones were shown to belong to a chondroitin sulfate proteoglycan by using antisera made against two peptides predicted from the cDNA sequence. These antisera were reactive with a proteoglycan fraction from fibroblasts after chondroitinase treatment of the fraction but not after treatment with heparinase or no treatment. Among the several polypeptides reactive with the anti-peptide antibodies the largest one, corresponding to a molecular weight of about 400,000, is likely to be the intact core protein, whereas the smaller polypeptides may be processing products or products of artifactual proteolysis. These results show that the amino acid sequence belongs to a proteoglycan core protein, and the sequence, therefore, provides a molecular definition to this proteoglycan. The lectin-related and growth factor-like sequences in the core protein of this proteoglycan suggest that it may play a role in intercellular signaling.
Highlights
Xgtl 1 expression library made from human fibroblast teoglycans are poorly understood, but they appear to range mRNA was screened with an antiserum made against from the elasticspace filler roleof the major cartilage proteoa proteoglycan fraction fromhuman fetal membranes. glycan [1,2] toroles as promoters or inhibitorosf cell adhesion
It seems likely that the specific characteristics of a proteoglycan are primarily determined by the structureof its core protein
On the NH2-ter- features of the variousproteoglycan core proteins, but definminal sideof the lectin-like domain the cDNA-derived itive structuralinformationonthe core proteinshas only amino acid sequence contains two epidermal growth recently been obtained through molecular cloning
Summary
Xgtl 1 expression library made from human fibroblast teoglycans are poorly understood, but they appear to range mRNA was screened with an antiserum made against from the elasticspace filler roleof the major cartilage proteoa proteoglycan fraction fromhuman fetal membranes. glycan [1,2] toroles as promoters or inhibitorosf cell adhesion. This amino acid sequence contains a domain that is stronglhyomologouswith the COOH-terminal core protein domain of the large aggregatingcartilage proteoglycan.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
