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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 inhibits hMOF HAT activity in vitro.(A) Recombinant hMOF. hMOF protein was measured with anti-hMOF antibody. (B) Insect cell expressed/purified HA-hMOF possessing HAT activity. Histones were visualized with Coomassie brilliant R250 blue (CBB) stain (middle panel) and H4K16ac was confirmed with acetylation-specific antibody (top panel). (C) Inhibitory effect of As2O3 on hMOF enzymatic activity.
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pone.0141014.g002: As2O3 inhibits hMOF HAT activity in vitro.(A) Recombinant hMOF. hMOF protein was measured with anti-hMOF antibody. (B) Insect cell expressed/purified HA-hMOF possessing HAT activity. Histones were visualized with Coomassie brilliant R250 blue (CBB) stain (middle panel) and H4K16ac was confirmed with acetylation-specific antibody (top panel). (C) Inhibitory effect of As2O3 on hMOF enzymatic activity.

Mentions: hMOF, as a catalytic subunit, forms two distinct cellular complexes-MSL and NSL in human cells [16,17]. Although the two complexes are composed of different proteins, both MSL and NSL possess acetylation activity on histone H4K16, suggesting that hMOF might be chiefly responsible for H4K16ac in cells [16,31]. Because As-induced decreases in H4K16ac may have caused hMOF activity loss, As was studied in the context of hMOF using an HAT assay. Insect cell expressed/purified hMOF (Fig 2A) with HAT activity (Fig 2B) was used to estimate the impact of As2O3 on hMOF activity. Data (Fig 2C) show that HAT activity of hMOF was blocked by As2O3 in a dose-dependent manner. As can inhibit several enzymes, such as GSH reductase [32] and lipoamide dehydrogenase [33]. Thus, As directly interact with hMOF protein. Using As-immobilized agarose (Fig 3A) we found that As-agarose pulled down hMOF protein (tubulin as positive control), but not HDAC4, indicating a physical interaction between As and hMOF (Fig 3B). These data were confirmed with competitive binding experiments with free As2O3 (10–100 μM). hMOF bound to As-agarose was gradually removed by increasing the amount of free As2O3 (Fig 3C and 3D).


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 inhibits hMOF HAT activity in vitro.(A) Recombinant hMOF. hMOF protein was measured with anti-hMOF antibody. (B) Insect cell expressed/purified HA-hMOF possessing HAT activity. Histones were visualized with Coomassie brilliant R250 blue (CBB) stain (middle panel) and H4K16ac was confirmed with acetylation-specific antibody (top panel). (C) Inhibitory effect of As2O3 on hMOF enzymatic activity.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4608833&req=5

pone.0141014.g002: As2O3 inhibits hMOF HAT activity in vitro.(A) Recombinant hMOF. hMOF protein was measured with anti-hMOF antibody. (B) Insect cell expressed/purified HA-hMOF possessing HAT activity. Histones were visualized with Coomassie brilliant R250 blue (CBB) stain (middle panel) and H4K16ac was confirmed with acetylation-specific antibody (top panel). (C) Inhibitory effect of As2O3 on hMOF enzymatic activity.
Mentions: hMOF, as a catalytic subunit, forms two distinct cellular complexes-MSL and NSL in human cells [16,17]. Although the two complexes are composed of different proteins, both MSL and NSL possess acetylation activity on histone H4K16, suggesting that hMOF might be chiefly responsible for H4K16ac in cells [16,31]. Because As-induced decreases in H4K16ac may have caused hMOF activity loss, As was studied in the context of hMOF using an HAT assay. Insect cell expressed/purified hMOF (Fig 2A) with HAT activity (Fig 2B) was used to estimate the impact of As2O3 on hMOF activity. Data (Fig 2C) show that HAT activity of hMOF was blocked by As2O3 in a dose-dependent manner. As can inhibit several enzymes, such as GSH reductase [32] and lipoamide dehydrogenase [33]. Thus, As directly interact with hMOF protein. Using As-immobilized agarose (Fig 3A) we found that As-agarose pulled down hMOF protein (tubulin as positive control), but not HDAC4, indicating a physical interaction between As and hMOF (Fig 3B). These data were confirmed with competitive binding experiments with free As2O3 (10–100 μM). hMOF bound to As-agarose was gradually removed by increasing the amount of free As2O3 (Fig 3C and 3D).

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