1989 Fiscal Year Final Research Report Summary
Molecular Biology of Differentiation of Tooth Forming Cells
| Project/Area Number |
63480410
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | TOKYO MEDICAL AND DENTAL UNIVERSITY |
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Principal Investigator |
SHIMOKAWA Hitoyata TOKYO MEDICAL AND DENTAL UNIVERSITY, DEPARTMENT OF BIOCHEMISTRY, ASSOCIATE PROFESSOR, 歯学部・生化学, 助教授 (80014257)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Enamel / Dentin / Mineralization / Amelogenin / Osteonectin / Differentiation |
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| Research Abstract |
1. Immunochemical and immunohistochemical localization of osteonectin.
Various tissues were investigated for the presence of osteonectin by means of immunochemical and immunohistochemical methods. Osteonectin could be demonstrated in active osteoblasts and osteoprogenitor cells as well as in young osteocytes. Osteonectin expression, however, was not confined to mineralizing tissue, but was distributed in many soft tissues.
2. cDNA cloning of osteonectin from expression libraries of bovine odontoblast.
To examine the identity of osteonectin with SPARC, cloning of osteonectin cDNA from lambda gtll expression library of bovine odontoblasts (non-cultured cells) was carried out. A 2.lkbp cDNA coding for osteonectin, isolated from the librafy, was sequenced. The nucleotide sequence predicted that osteonectin contained 304 amino acids including 17-residue signal peptide. The osteonectin sequence showed near identity (>90%) with another protein, SPARC.
3. Expression of SPARC/osteonectin transcript.
Osteonectin cDNA was used to analyze the expression of the corresponding transcript in various bovine fetal tissues. Several non-botie tissues, including skin, muscle, tendon, expressed the transcript in lesser extent than bone tissue.
4. Factors effect on the expression of osteonectin.
It was found that mRNA for alpha2(1) collagen and osteonectin were markedly increased in TGF-,beta -treated MG-63 and HOS human osteosarcoma cells. The messages of these proteins also increased in 1,25(OH)_2D_3 treated cells.
5. Human amelogenin gene.
Bovine amelogenin cDNA was used to isolate the amelogenin gene from a library of human genomic DNA fragments which contained a part of amelogenin coding region spanning approximately 13 kilobases. Analysis of this gene indicated the presence of four exons at least. It was revealed that the human amelogenin had a high homology with bovine, porcine, and murine amelogenins and had also hydrophilic carboxyterminus telopeptide.
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