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Arsenic Trioxide Reduces Global Histone H4 Acetylation at Lysine 16 through Direct Binding to Histone Acetyltransferase hMOF in Human Cells.

Liu D, Wu D, Zhao L, Yang Y, Ding J, Dong L, Hu L, Wang F, Zhao X, Cai Y, Jin J - PLoS ONE (2015)

Bottom Line: Our data show that decreased global H4K16ac and increased deacetyltransferase HDAC4 expression occurred in arsenic trioxide (As2O3)-exposed HeLa or HEK293T cells.However, depletion of HDAC4 did not affect global H4K16ac, and it could not raise H4K16ac in cells exposed to As2O3, suggesting that HDAC4 might not directly be involved in histone H4K16 de-acetylation.In an in vitro HAT assay, As2O3 directly inhibited hMOF activity. hMOF over-expression not only increased resistance to As and caused less toxicity, but also effectively reversed reduced H4K16ac caused by As exposure.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences, Jilin University, Changchun, Jilin 130012, China; School of Pharmacy, Changchun University of Traditional Chinese Medicine, Changchun 130117, China.

ABSTRACT
Histone post-translational modification heritably regulates gene expression involved in most cellular biological processes. Experimental studies suggest that alteration of histone modifications affects gene expression by changing chromatin structure, causing various cellular responses to environmental influences. Arsenic (As), a naturally occurring element and environmental pollutant, is an established human carcinogen. Recently, increasing evidence suggests that As-mediated epigenetic mechanisms may be involved in its toxicity and carcinogenicity, but how this occurs is still unclear. Here we present evidence that suggests As-induced global histone H4K16 acetylation (H4K16ac) partly due to the direct physical interaction between As and histone acetyltransferase (HAT) hMOF (human male absent on first) protein, leading to the loss of hMOF HAT activity. Our data show that decreased global H4K16ac and increased deacetyltransferase HDAC4 expression occurred in arsenic trioxide (As2O3)-exposed HeLa or HEK293T cells. However, depletion of HDAC4 did not affect global H4K16ac, and it could not raise H4K16ac in cells exposed to As2O3, suggesting that HDAC4 might not directly be involved in histone H4K16 de-acetylation. Using As-immobilized agarose, we confirmed that As binds directly to hMOF, and that this interaction was competitively inhibited by free As2O3. Also, the direct interaction of As and C2CH zinc finger peptide was verified by MAIDI-TOF mass and UV absorption. In an in vitro HAT assay, As2O3 directly inhibited hMOF activity. hMOF over-expression not only increased resistance to As and caused less toxicity, but also effectively reversed reduced H4K16ac caused by As exposure. These data suggest a theoretical basis for elucidating the mechanism of As toxicity.

No MeSH data available.


Related in: MedlinePlus

As2O3 binds directly to zinc finger (C2HC) peptide of hMOF.(A) Schematic of domain structure of hMOF. Chromo, chromatin organization modifier domain; C2HC, zinc finger domain; MYST-HAT, MYST-family histone acetyltransferase domain. The sequences from 208–231 and 247–270 residues are synthetic peptides of hMOF. (B) Analysis of MALDI-TOF mass spectra on interaction between As2O3 and synthetic peptides of hMOF. The molar ratio between the peptides and arsenic is 1:2. (C) UV absorption spectra of the zinc finger peptide. (D) Simulation of binding between zinc finger of hMOF and arsenic atoms. Three-dimensional structure based on the X-ray structure of hMOF (PDB code: 2GIV) [35]. All Cys residues on hMOF are represented in a ball-and-stick depiction. The zinc finger region-C2HC-type is dark cyan. Color coding: green, C; red, O; blue, N; yellow, S. The arsenic atom is pink.
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pone.0141014.g004: As2O3 binds directly to zinc finger (C2HC) peptide of hMOF.(A) Schematic of domain structure of hMOF. Chromo, chromatin organization modifier domain; C2HC, zinc finger domain; MYST-HAT, MYST-family histone acetyltransferase domain. The sequences from 208–231 and 247–270 residues are synthetic peptides of hMOF. (B) Analysis of MALDI-TOF mass spectra on interaction between As2O3 and synthetic peptides of hMOF. The molar ratio between the peptides and arsenic is 1:2. (C) UV absorption spectra of the zinc finger peptide. (D) Simulation of binding between zinc finger of hMOF and arsenic atoms. Three-dimensional structure based on the X-ray structure of hMOF (PDB code: 2GIV) [35]. All Cys residues on hMOF are represented in a ball-and-stick depiction. The zinc finger region-C2HC-type is dark cyan. Color coding: green, C; red, O; blue, N; yellow, S. The arsenic atom is pink.

Mentions: It has been reported that As directly binds to the zinc finger domain of PML-RARα which is a fusion protein containing sequences from the PML zinc finger protein and retinoic acid receptor alpha [34]. hMOF also contains a conserved Cys2HisCys (C2HC) zinc finger domain. To investigate As binding to the C2HC zinc finger domain of hMOF to perturb histone H4K16ac, four peptides containing the wild type C2HC domain, a C210/213A mutated C2HC domain, a C230A mutated C2HC domain, and without a C2HC domain of hMOF were synthesized (Fig 4A). Four peptides were incubated with As at room temperature for 1 hour. Mass spectra of peptides with/without As were analyzed by MALDI-TOF-MS. Compared to MS spectra of synthetic peptides of hMOF, a +72 Da mass shift was only observed in the wild type C2HC domain of hMOF after incubating peptides with As, but not in the other three peptides (Fig 4B). Binding of As (III) to the C2HC zinc finger peptide released three protons, suggesting that As (III) bound to three Cys of wild type C2HC peptide. These data were confirmed by UV absorbance detection. Fig 4C shows that the optical absorbance curve of the wild type C2HC peptide of hMOF moved up with increasing amounts of As (250-340nm). According to the 3-D structure of hMOF (PDB code: 2GIV) [35], we speculated a potential binding mode between As and the C2CH zinc finger of hMOF (Fig 4D).


Arsenic Trioxide Reduces Global Histone H4 Acetylation at Lysine 16 through Direct Binding to Histone Acetyltransferase hMOF in Human Cells.

Liu D, Wu D, Zhao L, Yang Y, Ding J, Dong L, Hu L, Wang F, Zhao X, Cai Y, Jin J - PLoS ONE (2015)

As2O3 binds directly to zinc finger (C2HC) peptide of hMOF.(A) Schematic of domain structure of hMOF. Chromo, chromatin organization modifier domain; C2HC, zinc finger domain; MYST-HAT, MYST-family histone acetyltransferase domain. The sequences from 208–231 and 247–270 residues are synthetic peptides of hMOF. (B) Analysis of MALDI-TOF mass spectra on interaction between As2O3 and synthetic peptides of hMOF. The molar ratio between the peptides and arsenic is 1:2. (C) UV absorption spectra of the zinc finger peptide. (D) Simulation of binding between zinc finger of hMOF and arsenic atoms. Three-dimensional structure based on the X-ray structure of hMOF (PDB code: 2GIV) [35]. All Cys residues on hMOF are represented in a ball-and-stick depiction. The zinc finger region-C2HC-type is dark cyan. Color coding: green, C; red, O; blue, N; yellow, S. The arsenic atom is pink.
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pone.0141014.g004: As2O3 binds directly to zinc finger (C2HC) peptide of hMOF.(A) Schematic of domain structure of hMOF. Chromo, chromatin organization modifier domain; C2HC, zinc finger domain; MYST-HAT, MYST-family histone acetyltransferase domain. The sequences from 208–231 and 247–270 residues are synthetic peptides of hMOF. (B) Analysis of MALDI-TOF mass spectra on interaction between As2O3 and synthetic peptides of hMOF. The molar ratio between the peptides and arsenic is 1:2. (C) UV absorption spectra of the zinc finger peptide. (D) Simulation of binding between zinc finger of hMOF and arsenic atoms. Three-dimensional structure based on the X-ray structure of hMOF (PDB code: 2GIV) [35]. All Cys residues on hMOF are represented in a ball-and-stick depiction. The zinc finger region-C2HC-type is dark cyan. Color coding: green, C; red, O; blue, N; yellow, S. The arsenic atom is pink.
Mentions: It has been reported that As directly binds to the zinc finger domain of PML-RARα which is a fusion protein containing sequences from the PML zinc finger protein and retinoic acid receptor alpha [34]. hMOF also contains a conserved Cys2HisCys (C2HC) zinc finger domain. To investigate As binding to the C2HC zinc finger domain of hMOF to perturb histone H4K16ac, four peptides containing the wild type C2HC domain, a C210/213A mutated C2HC domain, a C230A mutated C2HC domain, and without a C2HC domain of hMOF were synthesized (Fig 4A). Four peptides were incubated with As at room temperature for 1 hour. Mass spectra of peptides with/without As were analyzed by MALDI-TOF-MS. Compared to MS spectra of synthetic peptides of hMOF, a +72 Da mass shift was only observed in the wild type C2HC domain of hMOF after incubating peptides with As, but not in the other three peptides (Fig 4B). Binding of As (III) to the C2HC zinc finger peptide released three protons, suggesting that As (III) bound to three Cys of wild type C2HC peptide. These data were confirmed by UV absorbance detection. Fig 4C shows that the optical absorbance curve of the wild type C2HC peptide of hMOF moved up with increasing amounts of As (250-340nm). According to the 3-D structure of hMOF (PDB code: 2GIV) [35], we speculated a potential binding mode between As and the C2CH zinc finger of hMOF (Fig 4D).

Bottom Line: Our data show that decreased global H4K16ac and increased deacetyltransferase HDAC4 expression occurred in arsenic trioxide (As2O3)-exposed HeLa or HEK293T cells.However, depletion of HDAC4 did not affect global H4K16ac, and it could not raise H4K16ac in cells exposed to As2O3, suggesting that HDAC4 might not directly be involved in histone H4K16 de-acetylation.In an in vitro HAT assay, As2O3 directly inhibited hMOF activity. hMOF over-expression not only increased resistance to As and caused less toxicity, but also effectively reversed reduced H4K16ac caused by As exposure.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences, Jilin University, Changchun, Jilin 130012, China; School of Pharmacy, Changchun University of Traditional Chinese Medicine, Changchun 130117, China.

ABSTRACT
Histone post-translational modification heritably regulates gene expression involved in most cellular biological processes. Experimental studies suggest that alteration of histone modifications affects gene expression by changing chromatin structure, causing various cellular responses to environmental influences. Arsenic (As), a naturally occurring element and environmental pollutant, is an established human carcinogen. Recently, increasing evidence suggests that As-mediated epigenetic mechanisms may be involved in its toxicity and carcinogenicity, but how this occurs is still unclear. Here we present evidence that suggests As-induced global histone H4K16 acetylation (H4K16ac) partly due to the direct physical interaction between As and histone acetyltransferase (HAT) hMOF (human male absent on first) protein, leading to the loss of hMOF HAT activity. Our data show that decreased global H4K16ac and increased deacetyltransferase HDAC4 expression occurred in arsenic trioxide (As2O3)-exposed HeLa or HEK293T cells. However, depletion of HDAC4 did not affect global H4K16ac, and it could not raise H4K16ac in cells exposed to As2O3, suggesting that HDAC4 might not directly be involved in histone H4K16 de-acetylation. Using As-immobilized agarose, we confirmed that As binds directly to hMOF, and that this interaction was competitively inhibited by free As2O3. Also, the direct interaction of As and C2CH zinc finger peptide was verified by MAIDI-TOF mass and UV absorption. In an in vitro HAT assay, As2O3 directly inhibited hMOF activity. hMOF over-expression not only increased resistance to As and caused less toxicity, but also effectively reversed reduced H4K16ac caused by As exposure. These data suggest a theoretical basis for elucidating the mechanism of As toxicity.

No MeSH data available.


Related in: MedlinePlus