Cloning and Initial Characterization of Mouse Meltrin β and Analysis of the Expression of Four MetalloproteaseDisintegrins in Bone Cells

doi:10.1074/jbc.273.7.4180

Cloning and Initial Characterization of Mouse Meltrin β and Analysis of the Expression of Four MetalloproteaseDisintegrins in Bone Cells*

From the ^‡Department of Orthopaedics and Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510 and the ^¶Cellular Biochemistry and Biophysics Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021

Abstract

Here we report the cloning and initial biochemical characterization of the mouse metalloprotease/disintegrin/cysteine-rich (MDC) protein meltrin β and the analysis of the mRNA expression of four MDC genes (meltrin α, meltrin β, mdc9, and mdc15) in bone cells, including osteoclasts and osteoblasts. Like most other MDC proteins, the predicted meltrin β protein consists of a signal sequence, prodomain, metalloprotease domain with a predicted catalytic site, disintegrin domain, cysteine-rich region, epidermal growth factor repeat, transmembrane domain, and cytoplasmic domain with putative signaling motifs, such as potential SH3 ligand domains. Northern blot analysis indicates that meltrin β is widely expressed, with the highest expression in bone, heart, and lung. RNase protection studies revealed expression of all four MDC genes analyzed here in osteoblasts, whereas only mdc9 and mdc15mRNAs were detectable in osteoclast-like cells generated in vitro. Treatment of primary osteoblasts with 10 nmcalcitriol increased meltrin β expression more than 3-fold, and both meltrin α and meltrin β expression is apparently regulated in a differentiation-associated manner in a mouse osteoblastic cell line, MC3T3E1. Collectively, these results suggest that meltrin α and meltrinβ may play a role in osteoblast differentiation and/or function but are not likely to be involved in osteoclast fusion.

Footnotes

↵* This work was funded in part by grants to C. P. B. (National Institutes of Health R55GM51988 and National Science Foundation MCB-9631601), by Memorial Sloan-Kettering Cancer Center Support Grant NCI-P30-CA-08748, and by a grant from Hoechst Marion Roussel (Roussel-Uclaf, France), to R. B.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) AF019887.
↵§ Present address: University of Tokushima, School of Medicine, First Department of Internal Medicine, 3-18-15 Kuramoto-cho Tokushima-shi, Tokushima 770, Japan.
↵‖ Present address: Institute of Cellular and Molecular Biology, Research Laboratories of Schering AG, D-13342 Berlin, Germany.
↵** To whom correspondence should be addressed: Cellular Biochemistry and Biophysics Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, Box 368, 1275 York Ave., New York, NY 10021. Tel.: 212-639-2915; Fax: 212-717-3047; E-mail:c-blobel{at}ski.mskcc.org.
↵1 The abbreviations used are: MDC, metalloprotease, disintegrin, and cysteine-rich domains; OCL, osteoclast-like cell; PCR, polymerase chain reaction; GST, glutathioneS-transferase; POB, primary osteoblast.
↵2 H. Cai, J. Krätzschmar, and C. Blobel, manuscript in preparation.
↵3 J. White, personal communication.
↵4 L. Lum and C. Blobel, manuscript in preparation.
- Received June 20, 1997.
- Revision received September 8, 1997.
The American Society for Biochemistry and Molecular Biology, Inc.