Age-dependent alterations in mRNA level and promoter methylation of collagen alpha 1(I) gene in human periodontal ligament

In an attempt to understand the molecular mechanisms of age-dependent degen erative alteration in human periodontal tissues, we examined mRNA level and DNA methylation of collagen alpha 1(I) gene. Using healthy periodontal lig ament tissues from humans aged 9-76 years, we found that the collagen alpha 1(I) mRNA level decreased almost linearly with age. It was observed in bot h Northern blot and dot blot hybridization. Examination of DNA methylation in the collagen al(I) gene promoter region by its susceptibility to methyla tion-sensitive restriction enzyme followed by Southern blot analysis showed age-dependent increase of DNA methylation at -1705 and -80 positions locat ed upstream of the gene. The data suggest the possible importance of altera tions in collagen alpha 1(I) gene expression and its DNA methylation in pro moter region in age-dependent degeneration of periodontal ligament. (C) 199 9 Elsevier Science Ireland Ltd. All rights reserved.