Structure of human osteonectin based upon analysis of cDNA and genomic sequences.
Overlapping human bone osteonectin cDNAs were obtained by screening two independent human SaOS-2 lambda gt11 libraries using antibovine osteonectin monoclonal antibodies. One clone contains a 0.54-kb insert and the other a 1.9-kb insert. Insertion fragments from lambda clones were liberated by restriction digestion and subcloned into pUC19 for sequencing. Digestion of the 1.9-kb insert with EcoRI released 0.4- and 1.5-kb fragments. Sequencing analysis revealed that the 0.54- and 0.4-kb fragments are identical except for 150 nucleotides missing at the 5' region of the 0.4-kb fragment. The composite nucleotide sequence of human osteonectin has a total length of 2091 nucleotides and is comprised of 50 nucleotides of 5'-noncoding sequence, a coding segment for 303 amino acids, a termination codon, and 1114 nucleotides of 3'-noncoding sequence. The primary transcript codes for 286 amino acids of mature protein and a 17-residue amino-terminal hydrophobic signal peptide. Outstanding properties inferred from the primary structure are putative Ca2+ binding domains located in the glutamic acid rich NH2 terminus (residues 1-52) and two "EF"-hand domains in the C-terminal half of the protein (residues 165-176 and 257-286). The mature protein also contains a cysteine-rich, highly hydrophilic region homologous to the ovomucoid serine protease inhibitors (residues 76-132). Overlapping human genomic clones in lambda EMBL3 for osteonectin have been isolated and characterized. Intron/exon junction sequencing of the human osteonectin gene shows the presence of 10 exons and 9 introns. The mature protein is encoded by nine exons separated by eight introns.(ABSTRACT TRUNCATED AT 250 WORDS)
Villarreal
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XC
Department of Biochemistry, University of Vermont, Burlington 05405.
Mann
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KG
Long
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GL
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D001842:Bone and Bones / Q000378:metabolism; D002417:Cattle; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D005796:Genes; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D015676:Osteonectin / Q000235:genetics* / Q000276:immunology; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D000911:Antibodies, Monoclonal; D008562:Membrane Glycoproteins; D015676:Osteonectin; D004247:DNA