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Gelsolin gene silencing involving unusual hypersensitivities to dimethylsulfate and KMnO 4 in vivo footprinting on its promoter region
Author(s) -
Haga Kazunori,
Fujita Hisakazu,
Nomoto Minoru,
Sazawa Ataru,
Nakagawa Koji,
Harabayashi Toru,
Shinohara Nobuo,
Takimoto Masato,
omura Katsuya,
Kuzumaki Noboru
Publication year - 2004
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.20348
Subject(s) - gelsolin , biology , trichostatin a , gene silencing , histone , microbiology and biotechnology , cancer research , chromatin , chromatin immunoprecipitation , cancer cell , histone deacetylase , promoter , gene expression , cancer , gene , genetics , actin
We previously reported that gelsolin gene expression is reduced in various tumors. In an effort to gain further insights into the mechanism of gelsolin downregulation in tumors, we examined the in vivo properties of the gelsolin promoter in urinary bladder cancer cell lines. Neither mutation nor hypermethylation was responsible for gene silencing at the promoter. After exposure to trichostatin A (TSA), a histone deacetylase inhibitor, gelsolin promoter activity was markedly enhanced in the cancer cells, not in cells derived from normal tissue. Chromatin immunoprecipitation assays revealed that both histones H3 and H4 were hypoacetylated in the promoter region of the cancer cells, and the accumulation of acetylated histones was detected by TSA treatment. In vivo footprinting analysis revealed the presence of dimethylsulfate (DMS) hypersensitive site in the untranslated region around nucleotide −35 only in the cancer cells but not in cells derived from normal tissue, and analysis of KMnO 4 reactive nucleotides showed that the stem loop structure could be formed in vivo of the cancer cells. This novel stem loop structure may play a part in regulating the transcription of the gelsolin gene in the cancer cells. These results suggest that nucleosome accessibility through histone deacetylation and structural changes (DMS hypersensitivity and stem loop structure) in the promoter region form the basis of the mechanism leading to the silencing of gelsolin gene in human bladder cancer. © 2004 Wiley‐Liss, Inc.