Determination of Cementum Specific Proteins in Horse Molar Teeth

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15591983
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Functional basic dentistry
• Research Institution: Matsumoto Dental University
• Principal Investigator: FUKASAWA Kayoko Graduate School of Oral Medicine, Matsumoto Dental University, Associate Professor, 大学院・歯学独立研究科, 助教授 (60064698)
• Co-Investigator(Kenkyū-buntansha): SAHARA Noriyuki Matsumoto Dental University, Graduate School of Oral Medicine, Professor, 大学院・歯学独立研究科, 教授 (70064699) ; UDAGAWA Nobuyuki Matsumoto Dental University, Dept of Oral Biochemistry Medicine, Professor, 歯学部, 教授 (70245801) ; MIZOGUCHI Toshihide Matsumoto Dental University, Institute for Comprehensive Medical Science, Research associate, 総合歯科学研究所, 助手 (90329475) ; SHIGEKI Okumura Matsumoto Dental University, Dept of Oral Biochemistry Medicine, Research associate, 歯学部, 助手 (80350825) ; OZAWA Hidehiro Matsumoto Dental University, Graduate School of Oral Medicine, Professor, 大学院・歯学独立研究科, 教授 (60018413)
• Project Period (FY): 2003 – 2004
• Keywords: Cementum / EDTA soluble fraction / horse teeth / Type I Collagen / Protocadherin

Research Abstract

Cementum plays an important role in tooth regeneration ; however, the organization system has not yet been clarified. Our coworker, who has studied odontoclastic resorption in human deciduous teeth, found that the cementum completely covers the enamel tissues of horse molar teeth. In order to study the regeneration system of cementum, an EDTA soluble fraction extracted from horse cementum was analyzed.
The 30 kDa protein was isolated from the EDTA fraction of horse cementum by hydroxyapatite chromatography and SDS-PAGE. Tryptic peptides obtained by Edman degradation of the 30 kDa protein were QDTGPRGPRGPAGP(1), GXRGFSLDGVK(2) and GYEFVITEHXLA(3). A search of the UniProt protein sequence database with peptide 1 and peptide 2 showed significant similarity to the two regions of Procollagen al chain, residues 115-128 (93 %) and 266-277 (82 %), respectively. The peptide 3 showed the highest similarity (85 %) to the heptapeptide region of mouse Protocadherin 18. The 30 kDa protein would be a product from Type I collagen, a different splicing product translated from α1 procollagen gene or a novel protein. Protocadherin 18 has not been identified in the oral tissues. This is a first report to find a protocadherin 18-like protein in cementum.
Protocadherins are Ca^<2+>-dependent adhesion molecules, and are highly expressed in the central nervous system. It is well known that protocadherins are involved in many biological processes such as tissue morphogenesis or cell differentiation events. Therefore, the protocadherin 18-like protein found in cementum might be expected to be involved in the regenerating system of cementum.