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Zhaolong Liu, Le Yang, Yanxiang Sun, Xiaofeng Xie, Jianping Huang
ASF1a (anti-silencing function 1a), an evolutionarily conserved protein and a histone chaperone, is required for a variety of chromatin-mediated cellular processes. However, the function of ASF1a in innate immune response remains unclear. Here, we find that ASF1a is induced in Vesicular Stomatitis Virus (VSV)-infected macrophages in a manner that is dependent on IRF3 signal. ASF1a promotes VSV-triggered IFN-β production. Moreover, acetylation of H3K56 increases at the ifnb promoter after VSV infection, which is dependent on ASF1a...
October 2016: Molecular Immunology
Jongseong Kim, Sijie Wei, Jaehyoun Lee, Hongjun Yue, Tae-Hee Lee
Structural dynamics of a protein molecule is often critical to its function. Single-molecule methods provide efficient ways to investigate protein dynamics, although it is very challenging to achieve a millisecond or higher temporal resolution. Here we report spontaneous structural dynamics of the histone protein core in the nucleosome based on a single-molecule method that can reveal submillisecond dynamics by combining maximum likelihood estimation and fluorescence correlation spectroscopy. The nucleosome, comprising ∼147 bp DNA and an octameric histone protein core consisting of H2A, H2B, H3, and H4, is the fundamental packing unit of the eukaryotic genome...
September 1, 2016: Journal of Physical Chemistry. B
Xue Gao, Shu-Hai Lin, Feng Ren, Jin-Tao Li, Jia-Jia Chen, Chuan-Bo Yao, Hong-Bin Yang, Shu-Xia Jiang, Guo-Quan Yan, Di Wang, Yi Wang, Ying Liu, Zongwei Cai, Ying-Ying Xu, Jing Chen, Wenqiang Yu, Peng-Yuan Yang, Qun-Ying Lei
Besides the conventional carbon sources, acetyl-CoA has recently been shown to be generated from acetate in various types of cancers, where it promotes lipid synthesis and tumour growth. The underlying mechanism, however, remains largely unknown. We find that acetate induces a hyperacetylated state of histone H3 in hypoxic cells. Acetate predominately activates lipogenic genes ACACA and FASN expression by increasing H3K9, H3K27 and H3K56 acetylation levels at their promoter regions, thus enhancing de novo lipid synthesis, which combines with its function as the metabolic precursor for fatty acid synthesis...
2016: Nature Communications
Hanna Yang, Chang Seob Kwon, Yoonjung Choi, Daeyoup Lee
Nucleosome dynamics facilitated by histone turnover is required for transcription as well as DNA replication and repair. Histone turnover is often associated with various histone modifications such as H3K56 acetylation (H3K56Ac), H3K36 methylation (H3K36me), and H4K20 methylation (H4K20me). In order to correlate histone modifications and transcription-dependent histone turnover, we performed genome wide analyses for euchromatic regions in G2/M-arrested fission yeast. The results show that transcription-dependent histone turnover at 5' promoter and 3' termination regions is directly correlated with the occurrence of H3K56Ac and H4K20 mono-methylation (H4K20me1) in actively transcribed genes...
August 5, 2016: Biochemical and Biophysical Research Communications
Benjamin R Pointer, Martin Schmidt
Candida albicans is a dimorphic yeast commonly found on human mucosal membranes that switches from yeast to hyphal morphology in response to environmental factors. The change to hyphal growth requires histone H3 modifications by the yeast-specific histone acetyltransferase Rtt109. In addition to its role in morphogenesis, Rtt109-dependent acetylation of histone H3 lysine residues 9 and 56 has regulatory functions during DNA replication and repair. Boric acid (BA) is a broad-spectrum agent that specifically inhibits C...
July 2016: FEMS Microbiology Letters
Wesley Wei Wang, Yu Zeng, Bo Wu, Alexander Deiters, Wenshe R Liu
As a member of a highly conserved family of NAD(+)-dependent histone deacetylases, Sirt6 is a key regulator of mammalian genome stability, metabolism, and life span. Previous studies indicated that Sirt6 is hardwired to remove histone acetylation at H3K9 and H3K56. However, how Sirt6 recognizes its nucleosome substrates has been elusive due to the difficulty of accessing homogeneous acetyl-nucleosomes and the low activity of Sirt6 toward peptide substrates. Based on the fact that Sirt6 has an enhanced activity to remove long chain fatty acylation from lysine, we developed an approach to recombinantly synthesize histone H3 with a fatty acylated lysine, N(ε)-(7-octenoyl)-lysine (OcK), installed at a number of lysine sites and used these acyl-H3 proteins to assemble acyl-nucleosomes as active Sirt6 substrates...
July 15, 2016: ACS Chemical Biology
Zhu-Qin Zhang, Si-Chong Ren, Ying Tan, Zuo-Zhi Li, Xiaoqiang Tang, Ting-Ting Wang, De-Long Hao, Xiang Zhao, Hou-Zao Chen, De-Pei Liu
Sirt6 is a member of the class III histone deacetylase family which is associated with aging and longevity. Sirt6 deficient mice show an aging-like phenotype, while male transgenic mice of Sirt6 show increased longevity. Sirt6 acts as a tumor suppressor and deficiency of Sirt6 leads to cardiac hypertrophy and heart failure. Whether Sirt6 is involved in atherosclerosis development, the major cause of cardiovascular diseases, is unknown. We found that the expression of Sirt6 is lower in human atherosclerotic plaques than that in controls...
2016: Scientific Reports
Yesenia Rodriguez, John M Hinz, Marian F Laughery, John J Wyrick, Michael J Smerdon
Histone posttranslational modifications have been associated with changes in chromatin structure necessary for transcription, replication, and DNA repair. Acetylation is one of the most studied and best characterized histone posttranslational modifications, but it is not known if histone acetylation modulates base excision repair of DNA lesions in chromatin. To address this question, we generated nucleosome core particles (NCPs) containing site-specifically acetylated H3K14 or H3K56 and measured repair of uracil and single-nucleotide gaps...
May 20, 2016: Journal of Biological Chemistry
Devendra Kumar Gupta, Alok Tanala Patra, Lei Zhu, Archana Patkar Gupta, Zbynek Bozdech
DNA of malaria parasites, Plasmodium falciparum, is subjected to extraordinary high levels of genotoxic insults during its complex life cycle within both the mosquito and human host. Accordingly, most of the components of DNA repair machinery are conserved in the parasite genome. Here, we investigated the genome-wide responses of P. falciparum to DNA damaging agents and provided transcriptional evidence of the existence of the double strand break and excision repair system. We also showed that acetylation at H3K9, H4K8, and H3K56 play a role in the direct and indirect response to DNA damage induced by an alkylating agent, methyl methanesulphonate (MMS)...
2016: Scientific Reports
Keith M Jacobs, Sandeep Misri, Barbara Meyer, Suyash Raj, Cheri L Zobel, Barry P Sleckman, Dennis E Hallahan, Girdhar G Sharma
Normal tissue injury resulting from cancer radiotherapy is often associated with diminished regenerative capacity. We examined the relative radiosensitivity of normal stem cell populations compared with non-stem cells within several radiosensitive tissue niches and culture models. We found that these stem cells are highly radiosensitive, in contrast to their isogenic differentiated progeny. Of interest, they also exhibited a uniquely attenuated DNA damage response (DDR) and muted DNA repair. Whereas stem cells exhibit reduced ATM activation and ionizing radiation-induced foci, they display apoptotic pannuclear H2AX-S139 phosphorylation (γH2AX), indicating unique radioresponses...
April 15, 2016: Molecular Biology of the Cell
Yoav Voichek, Raz Bar-Ziv, Naama Barkai
Genome replication introduces a stepwise increase in the DNA template available for transcription. Genes replicated early in S phase experience this increase before late-replicating genes, raising the question of how expression levels are affected by DNA replication. We show that in budding yeast, messenger RNA (mRNA) synthesis rate is buffered against changes in gene dosage during S phase. This expression homeostasis depends on acetylation of H3 on its internal K56 site by Rtt109/Asf1. Deleting these factors, mutating H3K56 or up-regulating its deacetylation, increases gene expression in S phase in proportion to gene replication timing...
March 4, 2016: Science
J Cai, Y Zuo, T Wang, Y Cao, R Cai, F-L Chen, J Cheng, J Mu
Sirt6 is a histone deacetylase with NAD(+)-dependent activity. Sirt6 has been shown as a tumor suppressor partially via inhibiting the expression of c-Myc target genes and ribosome biogenesis. However, how to regulate Sirt6 activity is largely unknown. In this study, we identify that Sirt6 can be modified by small ubiquitin-like modifier. Sirt6 SUMOylation deficiency specifically decreases its deacetylation of H3K56 but not H3K9 in vivo. Mechanistically, we find that SUMOylation deficiency decreases Sirt6 binding with c-Myc, decreasing Sirt6 occupancy on the locus of c-Myc target genes...
September 15, 2016: Oncogene
Jiayi Yang, Xu Zhang, Jianxun Feng, He Leng, Shuqi Li, Junyu Xiao, Shaofeng Liu, Zhiyun Xu, Jiawei Xu, Di Li, Zhongshi Wang, Jingyang Wang, Qing Li
DNA replication-coupled (RC) nucleosome assembly is mediated by histone chaperones and is fundamental for epigenetic inheritance and maintenance of genomic integrity. The mechanisms that promote this process are only partially understood. Here, we show that the histone chaperone FACT (facilitates chromatin transactions), consisting of Spt16 and Pob3, promotes newly synthesized histone H3-H4 deposition. We describe an allele of Spt16 (spt16-m) that has a defect in binding to H3-H4 and impairs their deposition onto DNA...
February 9, 2016: Cell Reports
Jia Fei, Sharon E Torigoe, Christopher R Brown, Mai T Khuong, George A Kassavetis, Hinrich Boeger, James T Kadonaga
Chromatin comprises nucleosomes as well as nonnucleosomal histone-DNA particles. Prenucleosomes are rapidly formed histone-DNA particles that can be converted into canonical nucleosomes by a motor protein such as ACF. Here we show that the prenucleosome is a stable conformational isomer of the nucleosome. It consists of a histone octamer associated with ∼ 80 base pair (bp) of DNA, which is located at a position that corresponds to the central 80 bp of a nucleosome core particle. Monomeric prenucleosomes with free flanking DNA do not spontaneously fold into nucleosomes but can be converted into canonical nucleosomes by an ATP-driven motor protein such as ACF or Chd1...
December 15, 2015: Genes & Development
Morgan Bernier, Yi Luo, Kingsley C Nwokelo, Michelle Goodwin, Sarah J Dreher, Pei Zhang, Mark R Parthun, Yvonne Fondufe-Mittendorf, Jennifer J Ottesen, Michael G Poirier
H1 linker histones are highly abundant proteins that compact nucleosomes and chromatin to regulate DNA accessibility and transcription. However, the mechanisms that target H1 regulation to specific regions of eukaryotic genomes are unknown. Here we report fluorescence measurements of human H1 regulation of nucleosome dynamics and transcription factor (TF) binding within nucleosomes. H1 does not block TF binding, instead it suppresses nucleosome unwrapping to reduce DNA accessibility within H1-bound nucleosomes...
December 9, 2015: Nature Communications
Inkyung Jung, Jungmin Seo, Heun-Sik Lee, Lawrence W Stanton, Dongsup Kim, Jung Kyoon Choi
Histone residues can serve as platforms for specific regulatory function. Here we constructed a map of regulatory associations between histone residues and a wide spectrum of chromatin regulation factors based on gene expression changes by histone point mutations in Saccharomyces cerevisiae. Detailed analyses of this map revealed novel associations. Regarding the modulation of H3K4 and K36 methylation by Set1, Set2, or Jhd2, we proposed a role for H4K91 acetylation in early Pol II elongation, and for H4K16 deacetylation in late elongation and crosstalk with H3K4 demethylation for gene silencing...
December 21, 2015: FEBS Letters
Jongseong Kim, Jaehyoun Lee, Tae-Hee Lee
The nucleosome, comprising a histone protein core wrapped around by DNA, is the fundamental packing unit of DNA in cells. Lysine acetylation at the histone core elevates DNA accessibility in the nucleosome, the mechanism of which remains largely unknown. By employing our recently developed hybrid single molecule approach, here we report how the structural dynamics of DNA in the nucleosome is altered upon acetylation at histone H3 lysine 56 (H3K56) that is critical for elevated DNA accessibility. Our results indicate that H3K56 acetylation facilitates the structural dynamics of the DNA at the nucleosome termini that spontaneously and repeatedly open and close on a ms time scale...
December 3, 2015: Journal of Physical Chemistry. B
Zoulfia Darieva, Aaron Webber, Stacey Warwood, Andrew D Sharrocks
The re-assembly of chromatin following DNA replication is a critical event in the maintenance of genome integrity. Histone H3 acetylation at K56 and phosphorylation at T45 are two important chromatin modifications that accompany chromatin assembly. Here we have identified the protein kinase Pkc1 as a key regulator that coordinates the deposition of these modifications in S. cerevisiae under conditions of replicative stress. Pkc1 phosphorylates the histone acetyl transferase Rtt109 and promotes its ability to acetylate H3K56...
October 15, 2015: ELife
Nicola A Philbrook, Louise M Winn
Exposure to the ubiquitous environmental pollutant benzene is positively correlated with leukemia in adults and may be associated with childhood leukemia following in utero exposure. While numerous studies implicate oxidative stress and DNA damage as playing a role in benzene-mediated carcinogenicity, emerging evidence suggests that alterations in epigenetic regulations may be involved. The present study aimed to determine whether DNA methylation and/or various histone modifications were altered following in utero benzene exposure in CD-1 mice...
November 15, 2015: Toxicology and Applied Pharmacology
Carmela Irene, James F Theis, David Gresham, Patricia Soteropoulos, Carol S Newlon
Long gaps between active replication origins probably occur frequently during chromosome replication, but little is known about how cells cope with them. To address this issue, we deleted replication origins from S. cerevisiae chromosome III to create chromosomes with long interorigin gaps and identified mutations that destabilize them [originless fragment maintenance (Ofm) mutations]. ofm6-1 is an allele of HST3, a sirtuin that deacetylates histone H3K56Ac. Hst3p and Hst4p are closely related, but hst4Δ does not cause an Ofm phenotype...
February 2016: Molecular Genetics and Genomics: MGG
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