Hypermethylation of CpGs in the Promoter of the COL1A1 Gene in the Aged Periodontal Ligament
T. Ohi1,2,
Y. Uehara3,
M. Takatsu1,
M. Watanabe1, and
T. Ono3,*
1 Division of Aging and Geriatric Dentistry, Department of Oral Function and Morphology, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aobaku, Sendai 980-8575, Japan;
2 The Tohoku University 21st Century COE Program Comprehensive Research and Education Center for Planning of Drug Development and Clinical Evaluation (CRESCENDO), 2-1, Seiryo-machi, Aobaku, Sendai 980-8575, Japan; and
3 Department of Cell Biology, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aobaku, Sendai 980-8575, Japan
View larger version (11K):
[in a new window]
|
Figure 1. CpG site map of the human collagen  1(I) gene (COL1A1) gene. The first exon is indicated by the open rectangular box. The CpG sites are shown by the short vertical lines below the map. The three areas examined in the present study are indicated below the CpG sites by dark rectangular bars. The numbers on the map show the location of nucleotides when the initiation site for transcription is designated as +1.
|
|
View larger version (42K):
[in a new window]
|
Figure 2. DNA methylation profiles in the proximal promoter region. (A) A detailed map of CpG sites in the region. The short vertical lines indicate the locations of CpG sites, and the numbers below them show the exact location in the COL1A1 map. The transcription start site is +1. (B) Methylation of cytosine at CpG sites in human periodontal ligament samples from donors of 8 different ages. The numbers at the left side of the arrays of circles show the DNA clone number. Open circles show no methylation, and the closed circles indicate methylated cytosine. Each circle represents the CpG site shown in (A), in the same order. The DNA clones from the periodontal ligaments of older people show a high incidence of methylated cytosines. (C) The degree of methylation at each CpG site was calculated as a percentage of the methylated cytosines seen in all clones for each sample. The averages of the frequencies of methylation at each CpG site in four younger and four older humans were calculated with their standard deviations. Open columns represent younger humans, and the closed columns, older humans. The bars on each column show standard deviations. Asterisks above the bars show that the levels of methylation are different between younger and older tissues at a statistically significant level, p < 0.05.
|
|
View larger version (19K):
[in a new window]
|
Figure 3. DNA methylation profiles in the distal promoter and first intron region. (A,C) Detailed maps of CpG sites in the distal promoter and 1st intron region, respectively. The short vertical bars indicate the location of CpG sites, and the numbers below the bars show the exact location in the COL1A1 map. (B,D) The degree of methylation at each CpG site. The averages of the frequencies of methylation at each CpG site in four younger and four older humans were calculated with their standard deviations. Open columns represent younger humans, and the closed columns, older humans. The bars on each column show standard deviations. The asterisks above the bars indicate that the levels of methylation are different between younger and older tissues at a statistically significant level, p < 0.05.
|
|
Copyright © 2006 Institutional Access Guidelines
