DNA methylation and chromatin structure regulate T cell perforin gene expression.
Perforin is a cytotoxic effector molecule expressed in NK cells and a subset of T cells. The mechanisms regulating its expression are incompletely understood. We observed that DNA methylation inhibition could increase perforin expression in T cells, so we examined the methylation pattern and chromatin structure of the human perforin promoter and upstream enhancer in primary CD4(+) and CD8(+) T cells as well as in an NK cell line that expresses perforin, compared with fibroblasts, which do not express perforin. The entire region was nearly completely unmethylated in the NK cell line and largely methylated in fibroblasts. In contrast, only the core promoter was constitutively unmethylated in primary CD4(+) and CD8(+) cells, and expression was associated with hypomethylation of an area residing between the upstream enhancer at -1 kb and the distal promoter at -0.3 kb. Treating T cells with the DNA methyltransferase inhibitor 5-azacytidine selectively demethylated this area and increased perforin expression. Selective methylation of this region suppressed promoter function in transfection assays. Finally, perforin expression and hypomethylation were associated with localized sensitivity of the 5' flank to DNase I digestion, indicating an accessible configuration. These results indicate that DNA methylation and chromatin structure participate in the regulation of perforin expression in T cells.
University of Michigan, Ann Arbor, MI 48109, USA.
Qianjin
Q
Lu
Ailing
A
Wu
Donna
D
Ray
Chun
C
Deng
John
J
Attwood
Samir
S
Hanash
Matthew
M
Pipkin
Mathias
M
Lichtenheld
Bruce
B
Richardson
D020121:5' Untranslated Regions / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D000818:Animals; D001374:Azacitidine / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D002843:Chromatin / Q000737:chemistry* / Q000502:physiology*; D019175:DNA Methylation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D051379:Mice; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D016176:T-Lymphocyte Subsets / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*
D020121:5' Untranslated Regions; D002843:Chromatin; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger; D054353:Perforin; D001374:Azacitidine