Effect of DNA methylation and chromatin structure on ITGAL expression.
LFA-1 (CD11a/CD18, alpha L beta 2) is an integrin expressed in a tissue-specific fashion and is important in inflammatory and immune responses. Promoter analysis has identified transcription factors that may be involved in CD11a expression, but the mechanisms contributing to its tissue-specific expression are incompletely characterized. In this report we have asked if DNA methylation and/or chromatin structure could contribute to tissue-specific CD11a expression. Bisulfite sequencing was used to compare methylation patterns in the promoter and 5' flanking regions of the ITGAL gene, encoding CD11a, in normal human T cells, which express LFA-1, and fibroblasts, which do not. The region was found to be heavily methylated in fibroblasts but not T cells, and methylation correlated with an inactive chromatin configuration as analyzed by deoxyribonuclease 1 sensitivity. Patch methylation of the promoter region revealed that promoter activity was methylation-sensitive but that methylation of the 5' flanking regions more than 500 base pairs 5' to the transcription start site could also suppress promoter function. Treating fibroblasts with a DNA methylation inhibitor decreased ITGAL promoter methylation and increased CD11a messenger RNA. The results thus indicate that methylation and chromatin structure may contribute to the tissue-specific expression of CD11a.
Lu
Qianjin
Q
Department of Medicine, University of Michigan and the Ann Arbor VA Hospital, 48109-0940, USA.
Ray
Donna
D
Gutsch
David
D
Richardson
Bruce
B
D024506:5' Flanking Region / Q000235:genetics; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D019175:DNA Methylation; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D016169:Lymphocyte Function-Associated Antigen-1 / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D013601:T-Lymphocytes / Q000378:metabolism
D002843:Chromatin; D016169:Lymphocyte Function-Associated Antigen-1