Read by QxMD icon Read


Kate E Hawkins, Dafni Moschidou, Danilo Faccenda, Wasco Wruck, Alex Martin-Trujillo, Kwan-Leong Hau, Anna Maria Ranzoni, Veronica Sanchez-Freire, Fabio Tommasini, Simon Eaton, Paolo De Coppi, David Monk, Michelangelo Campanella, Adrian J Thrasher, James Adjaye, Pascale V Guillot
Restoring pluripotency using chemical compounds alone would be a major step forward in developing clinical-grade pluripotent stem cells, but this has not yet been reported in human cells. We previously demonstrated that VPA_AFS cells, human amniocytes cultivated with valproic acid (VPA) acquired functional pluripotency while remaining distinct from human embryonic stem cells (hESCs), questioning the relationship between the modulation of cell fate and molecular regulation of the pluripotency network. Here, we used single-cell analysis and functional assays to reveal that VPA treatment resulted in a homogeneous population of self-renewing non-transformed cells that fulfill the hallmarks of pluripotency, i...
February 1, 2017: Molecular Therapy: the Journal of the American Society of Gene Therapy
Jaehyoun Lee, Tae-Hee Lee
Nucleosomes impose physical barriers to DNA-templated processes, playing important roles in eukaryotic gene regulation. DNA is packaged into nucleosomes by histone proteins mainly through strong electrostatic interactions that can be modulated by various post-translational histone modifications. Investigating the dynamics of histone dissociation from the nucleosome and how it is altered upon histone modifications is important for understanding eukaryotic gene regulation mechanisms. In particular, histone H2A-H2B dimer displacement in the nucleosome is one of the most important and earliest steps of histone dissociation...
February 8, 2017: Biochemistry
Han-Tsang Wu, Yi-Chih Kuo, Jung-Jyh Hung, Chi-Hung Huang, Wei-Yi Chen, Teh-Ying Chou, Yeh Chen, Yi-Ju Chen, Yu-Ju Chen, Wei-Chung Cheng, Shu-Chun Teng, Kou-Juey Wu
Intratumoural hypoxia induces HIF-1α and promotes tumour progression, metastasis and treatment resistance. HIF-1α stability is regulated by VHL-E3 ligase-mediated ubiquitin-dependent degradation; however, the hypoxia-regulated deubiquitinase that stabilizes HIF-1α has not been identified. Here we report that HAUSP (USP7) deubiquitinase deubiquitinates HIF-1α to increase its stability, induce epithelial-mesenchymal transition and promote metastasis. Hypoxia induces K63-linked polyubiquitinated HAUSP at lysine 443 to enhance its functions...
December 9, 2016: Nature Communications
Muthukumaran Rajagopalan, Sangeetha Balasubramanian, Ilya Ioshikhes, Amutha Ramaswamy
Post translational modifications have a profound role in the regulation of several biological processes such as transcription, replication, and DNA repair. Acetylation and phosphorylation form a major class of post translational modifications involved in nucleosomal regulation by modifying its structure. The effect of post translational modifications on nucleosome structure could be better explored when the molecular trajectories explaining the time dependent structural evolution over a period of time is examined at the atomic level...
December 8, 2016: European Biophysics Journal: EBJ
Abhinav K Jain, Yuanxin Xi, Ryan McCarthy, Kendra Allton, Kadir C Akdemir, Lalit R Patel, Bruce Aronow, Chunru Lin, Wei Li, Liuqing Yang, Michelle C Barton
Recent evidence suggests that lncRNAs play an integral regulatory role in numerous functions, including determination of cellular identity. We determined global expression (RNA-seq) and genome-wide profiles (ChIP-seq) of histone post-translational modifications and p53 binding in human embryonic stem cells (hESCs) undergoing differentiation to define a high-confidence set of 40 lncRNAs, which are p53 transcriptional targets. We focused on lncRNAs highly expressed in pluripotent hESCs and repressed by p53 during differentiation to identify lncPRESS1 as a p53-regulated transcript that maintains hESC pluripotency in concert with core pluripotency factors...
December 1, 2016: Molecular Cell
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)...
April 1, 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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"