Matrix Gla protein is differentially expressed during the deposition of a calcified matrix by vascular pericytes

PCR-based subtractive hybridisation was used to identify genes up-regulated when pericytes undergo osteogenic differentiation and deposit a calcified matrix, cDNA pools mere generated from confluent pericytes and from pericyte cultures containing calcified nodules, A pericyte cDNA library was screened with the product of the subtraction procedure (calcified minus confluent cDNA) and the majority of the positive clones mere identified as matrix Gla protein (MGP). Northern analysis and immunohistochemistry demonstrated that MGP was only expressed by pericytes in calcified nodules, Antibodies to MGP inhibited the deposition of a calcified matrix by pericytes, suggesting that MGP regulates both cell differentiation and calcification. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.