Structure and Expression of Osteonectin Mrna in Human Tissue
Bone Research Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892. Connective Tissue Research
(Impact Factor: 1.61).
02/1990; 24(1):17-28. DOI: 10.3109/03008209009152419
A cDNA encoding osteonectin was isolated from a human bone cell cDNA library and used to examine osteonectin protein structure, mRNA structure and expression in human tissue. The deduced protein sequence shows complete identity with a recently isolated placental form and extensive homology to mouse and bovine counterparts. The protein is rich in cysteine residues, which are conserved between species except for cys 194 which is only present in the bovine. In the human, osteonectin mRNA is of two sizes, 2.3 and 3.0 kb, the former being dominant in all tissues studied. Human mRNA was detected in the Ewing sarcoma and in non-bone cell and tissue sources. The potential folded structure of osteonectin mRNA was estimated, based on computer predictions, and indicates the presence of a bulge at the 5' end of the message which includes the start of translation. Southern analysis of human genomic DNA using radiolabeled osteonectin cDNA as probe demonstrates a simple banding pattern confirming earlier studies that the osteonectin gene is present in one copy per haploid human genome.
Available from: Sanna Oksjoki
- "The mRNAs for core proteins of small proteoglycans decorin, biglycan and fibromodulin were detected with probes pMDcn-1, pMBgn-1 and pMFmn-1 (A.-M.Säämänen, H.Salminen and E.Vuorio, unpublished), those for syndecan-1 with clone PM-4 (Saunders et al., 1989), those for MMP-2, 9 and 13 with clones pK-191 (Huhtala et al., 1990), M92 KD-1 (Reponen et al., 1994) and pMMMP-13 respectively (M.Perälä and E.Vuorio, unpublished), and those for TIMP-1, 2 and 3 with clones pMTIMP-1, pMTIMP-2 and pMTIMP-3 respectively (K.Joronen, V.Glumoff and E.Vuorio, unpublished). Osteonectin mRNA was detected using clone pHon 164 (Young et al., 1990), and the 28 S rRNA with clone 341–1 (Iruela-Arispe et al., 1991). The inserts were liberated from the plasmids by appropriate restriction enzymes for labelling by the random priming method. "
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ABSTRACT: In the ovary, differentiation of germinal cells into primordial follicles, functional ovulatory follicles and corpus luteum, all take place in a connective tissue matrix. We postulated that extracellular matrix (ECM) of the ovary participates actively in ovarian functions. To test this, the mRNA levels for several ECM components were determined in the mouse ovary at six distinct stages of the 4-day oestrous cycle. Northern analysis revealed statistically significant cyclic expression patterns for the mRNAs coding for type III, IV and VI collagens as well as for the small proteoglycan, biglycan, and for syndecan-1 and osteonectin. The cyclic changes observed in the mRNAs for these structural components exceeded those for matrix metalloproteinases (MMP)-2, -9 and -13, and for tissue inhibitors of matrix metalloproteinases (TIMP)-1, -2 and -3, where the changes were not statistically significant, despite their apparent role in ECM remodelling in the ovary. These observations support the hypothesis that cyclic changes in the production and degradation of ECM are part of normal ovarian function connected with follicular maturation, rupture and corpus luteum formation.
Available from: nih.gov
- "The first cosmid, SPARC, was obtained by screening a total human genomic cosmid library in pWE15 (Stratagene Cloning Systems ) by using standard procedures (Sambrook et al. 1989) with a 0.6-kb EcoRI fragment of an osteonectin cDNA clone. The EcoRI fragment was derived from the 5' end of the gene (Young et al. 1990). The gene designation for osteonectin is "SPARC." "
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ABSTRACT: Treacher Collins syndrome (TCOF1) is an autosomal dominant disorder of craniofacial development, the features of which include conductive hearing loss and cleft palate. The TCOF1 locus has been localized to chromosome 5q32-33.2. In the present study we have used the combined techniques of genetic linkage analysis and fluorescence in situ hybridization (FISH) to more accurately define the TCOF1 critical region. Cosmids IG90 and SPARC, which map to distal 5q, encompass two and one hypervariable microsatellite markers, respectively. The heterozygosity values of these three markers range from .72 to .81. Twenty-two unrelated TCOF1 families have been analyzed for linkage to these markers. There is strong evidence demonstrating linkage to all three markers, the strongest support for positive linkage being provided by haplotyping those markers at the locus encompassed by the cosmid IG90 (Zmax = 19.65; theta = .010). FISH to metaphase chromosomes and interphase nuclei established that IG90 lies centromeric to SPARC. This information combined with the data generated by genetic linkage analysis demonstrated that the TCOF1 locus is closely flanked proximally by IG90 and distally by SPARC.
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ABSTRACT: The expression of osteonectin gene was studied in developing human fetuses by Northern analysis and in situ hybridization. The highest levels of osteonectin mRNA were detected in RNA extracted from calvarial bones, growth plates, and skin. Low mRNA levels were present in several parenchymal tissues. In situ hybridization of developing long bones revealed three cell types with high osteonectin mRNA levels: osteoblasts, cells of the periosteum, and hypertrophic chondrocytes. Weaker signals were detected in osteocytes, fibroblasts of tendons, ligaments and skin, and in cells of the epidermis. Apart from the hypertrophic chondrocytes, only low osteonectin mRNA levels were seen in cartilage. The localization of osteonectin mRNA in fetal growth plates is consistent with the hypothesis that the protein plays a role in the mineralization of bone and cartilage matrices.
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