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histone chaperone

Gerry Q Tonkin-Hill, Leily Trianty, Rintis Noviyanti, Hanh H T Nguyen, Boni F Sebayang, Daniel A Lampah, Jutta Marfurt, Simon A Cobbold, Janavi S Rambhatla, Malcolm J McConville, Stephen J Rogerson, Graham V Brown, Karen P Day, Ric N Price, Nicholas M Anstey, Anthony T Papenfuss, Michael F Duffy
Within the human host, the malaria parasite Plasmodium falciparum is exposed to multiple selection pressures. The host environment changes dramatically in severe malaria, but the extent to which the parasite responds to-or is selected by-this environment remains unclear. From previous studies, the parasites that cause severe malaria appear to increase expression of a restricted but poorly defined subset of the PfEMP1 variant, surface antigens. PfEMP1s are major targets of protective immunity. Here, we used RNA sequencing (RNAseq) to analyse gene expression in 44 parasite isolates that caused severe and uncomplicated malaria in Papuan patients...
March 12, 2018: PLoS Biology
Geetha S Hewawasam, Karthik Dhatchinamoorthy, Mark Mattingly, Chris Seidel, Jennifer L Gerton
Correct localization of the centromeric histone variant CenH3/CENP-A/Cse4 is an important part of faithful chromosome segregation. Mislocalization of CenH3 could affect chromosome segregation, DNA replication and transcription. CENP-A is often overexpressed and mislocalized in cancer genomes, but the underlying mechanisms are not understood. One major regulator of Cse4 deposition is Psh1, an E3 ubiquitin ligase that controls levels of Cse4 to prevent deposition into non-centromeric regions. We present evidence that Chromatin assembly factor-1 (CAF-1), an evolutionarily conserved histone H3/H4 chaperone with subunits shown previously to interact with CenH3 in flies and human cells, regulates Cse4 deposition in budding yeast...
March 7, 2018: Nucleic Acids Research
Francesca Mattiroli, Yajie Gu, Karolin Luger
Nucleosomes organize the eukaryotic genome into chromatin. In cells, nucleosome assembly relies on the activity of histone chaperones, proteins with high binding affinity to histones. At least a subset of histone chaperones promotes histone deposition in vivo . However, it has been challenging to characterize this activity, due to the lack of quantitative assays. Here we developed a quantitative nucleosome assembly (NAQ) assay to measure the amount of nucleosome formation in vitro . This assay relies on a Micrococcal nuclease (MNase) digestion step that yields DNA fragments protected by the deposited histone proteins...
February 5, 2018: Bio-protocol
Laura L McCullough, Zaily Connell, Hua Xin, Vasily M Studitsky, Alexey V Feofanov, Maria E Valieva, Tim Formosa
The essential histone chaperone FAcilitates Chromatin Transcription (FACT) promotes both nucleosome assembly and disassembly. FACT is a heterodimer of Spt16 with either SSRP1 or Pob3, differing primarily by the presence of a high-mobility group B (HMGB) DNA-binding domain furnished only by SSRP1. Yeast FACT lacks the intrinsic HMGB domain found in SSRP1-based homologs such as human FACT, but yeast FACT activity is supported by Nhp6, which is a freestanding, single HMGB domain protein. The importance of histone binding by FACT domains has been established, but the roles of DNA binding activity remain poorly understood...
March 7, 2018: Journal of Biological Chemistry
Christine M Kondratick, Jacob M Litman, Kurt V Shaffer, M Todd Washington, Lynne M Dieckman
Proliferating cell nuclear antigen (PCNA), a homotrimeric protein, is the eukaryotic sliding clamp that functions as a processivity factor for polymerases during DNA replication. Chromatin association factor 1 (CAF-1) is a heterotrimeric histone chaperone protein that is required for coupling chromatin assembly with DNA replication in eukaryotes. CAF-1 association with replicating DNA, and the targeting of newly synthesized histones to sites of DNA replication and repair requires its interaction with PCNA. Genetic studies have identified three mutant forms of PCNA in yeast that cause defects in gene silencing and exhibit altered association of CAF-1 to chromatin in vivo, as well as inhibit binding to CAF-1 in vitro...
2018: PloS One
Santiago Martínez-Calvillo, Gabriela Romero-Meza, Juan C Vizuet-de-Rueda, Luis E Florencio-Martínez, Rebeca Manning-Cela, Tomás Nepomuceno-Mejía
The Trypanosomatid family includes flagellated parasites that cause fatal human diseases. Remarkably, protein-coding genes in these organisms are positioned in long tandem arrays that are transcribed polycistronically. However, the knowledge about regulation of transcription initiation and termination in trypanosomatids is scarce. The importance of epigenetic regulation in these processes has become evident in the last years, as distinctive histone modifications and histone variants have been found in transcription initiation and termination regions...
February 2018: Current Genomics
Huimin Qiao, Yanxin Li, Chao Feng, Shuguang Duo, Fen Ji, Jianwei Jiao
The precise function and role of nucleosome assembly protein 1-like 1 (Nap1l1) in brain development are unclear. Here, we find that Nap1l1 knockdown decreases neural progenitor cell (NPC) proliferation and induces premature neuronal differentiation during cortical development. A similar deficiency in embryonic neurogenesis was observed in Nap1l1 knockout (KO) mice, which were generated using the CRISPR-Cas9 system. RNA sequencing (RNA-seq) analysis indicates that Ras-associated domain family member 10 (RassF10) may be the downstream target of Nap1l1...
February 27, 2018: Cell Reports
Jonathan Nye, Daniël P Melters, Yamini Dalal
Histone chaperones are indispensable regulators of chromatin structure and function. Recent work has shown that they are frequently mis-regulated in cancer, which can have profound consequences on tumor growth and survival. Here, we focus on chaperones for the essential H3 histone variants H3.3 and CENP-A, specifically HIRA, DAXX/ATRX, DEK, and HJURP. This review summarizes recent studies elucidating their roles in regulating chromatin and discusses how cancer-specific chromatin interactions can be exploited to target cancer cells...
2018: F1000Research
Ting-Hsiang Huang, Faith Fowler, Chin-Chuan Chen, Zih-Jie Shen, Barry Sleckman, Jessica K Tyler
The access-repair-restore model for the role of chromatin in DNA repair infers that chromatin is a mere obstacle to DNA repair. However, here we show that blocking chromatin assembly, via knockdown of the histone chaperones ASF1 or CAF-1 or a mutation that prevents ASF1A binding to histones, hinders Rad51 loading onto ssDNA during homologous recombination. This is a consequence of reduced recruitment of the Rad51 loader MMS22L-TONSL to ssDNA, resulting in persistent RPA foci, extensive DNA end resection, persistent activation of the ATR-Chk1 pathway, and cell cycle arrest...
March 1, 2018: Molecular Cell
Alessandro Borgia, Madeleine B Borgia, Katrine Bugge, Vera M Kissling, Pétur O Heidarsson, Catarina B Fernandes, Andrea Sottini, Andrea Soranno, Karin J Buholzer, Daniel Nettels, Birthe B Kragelund, Robert B Best, Benjamin Schuler
Molecular communication in biology is mediated by protein interactions. According to the current paradigm, the specificity and affinity required for these interactions are encoded in the precise complementarity of binding interfaces. Even proteins that are disordered under physiological conditions or that contain large unstructured regions commonly interact with well-structured binding sites on other biomolecules. Here we demonstrate the existence of an unexpected interaction mechanism: the two intrinsically disordered human proteins histone H1 and its nuclear chaperone prothymosin-α associate in a complex with picomolar affinity, but fully retain their structural disorder, long-range flexibility and highly dynamic character...
March 1, 2018: Nature
Sarmishtha De, Daniel J Lindner, Claire Coleman, Gary Wildey, Afshin Dowlati, George R Stark
Traditional treatments of small cell lung cancer (SCLC) with cisplatin, a standard of care therapy, spare the tumor-initiating cells (TIC) that mediate drug resistance. Here we report a novel therapeutic strategy that preferentially targets TIC in SCLC in which cisplatin is combined with CBL0137, an inhibitor of the histone chaperone facilitates chromatin transcription (FACT), which is highly expressed in TIC. Combination of cisplatin and CBL0137 killed patient-derived and murine SCLC cell lines synergistically...
February 13, 2018: Cancer Research
Besio Roberta, Iula Giusy, Garibaldi Nadia, Cipolla Lina, Sabbioneda Simone, Biggiogera Marco, C Marini Joan, Rossi Antonio, Forlino Antonella
The clinical phenotype in osteogenesis imperfecta (OI) is attributed to the dominant negative function of mutant type I collagen molecules in the extracellular matrix, by altering its structure and function. Intracellular retention of mutant collagen has also been reported, but its effect on cellular homeostasis is less characterized. Using OI patient fibroblasts carrying mutations in the α1(I) and α2(I) chains we demonstrate that retained collagen molecules are responsible for endoplasmic reticulum (ER) enlargement and activation of the unfolded protein response (UPR) mainly through the eukaryotic translation initiation factor 2 alpha kinase 3 (PERK) branch...
February 9, 2018: Biochimica et Biophysica Acta
Jungmin Yoon, Seung Joong Kim, Sojin An, Saehyun Cho, Alexander Leitner, Taeyang Jung, Ruedi Aebersold, Hans Hebert, Uhn-Soo Cho, Ji-Joon Song
Importin4 transports histone H3/H4 in complex with Asf1a to the nucleus for chromatin assembly. Importin4 recognizes the nuclear localization sequence located at the N-terminal tail of histones. Here, we analyzed the structures and interactions of human Importin4, histones and Asf1a by cross-linking mass spectrometry (XL-MS), X-ray crystallography, negative-stain electron microscopy, small-angle X-ray scattering and integrative modeling. The XL-MS data showed that the C-terminal region of Importin4 was extensively crosslinked with the histone H3 tail...
January 30, 2018: Journal of Molecular Biology
Mohammad Ali Okhovat, Katayoun Ziari, Reza Ranjbaran, Negin Nikouyan
Alpha-hemoglobin stabilizing protein (AHSP) is a molecular chaperone that can reduce the damage caused by excess free α-globin to erythroid cells in patients with impaired β-globin chain synthesis. We assessed the effect of sodium phenylbutyrate and sodium valproate, two histone deacetylase inhibitors (HDIs) that are being studied for the treatment of hemoglobinopathies, on the expression of AHSP, BCL11A (all isoforms), γ-globin genes (HBG1/2), and some related transcription factors including GATA1, NFE2, EKLF, KLF4, and STAT3...
2018: PloS One
Balázs Barna, Katalin Gémes, Mónika Domoki, Dóra Bernula, Györgyi Ferenc, Balázs Bálint, István Nagy, Attila Fehér
Plant nucleosome assembly protein-related proteins (NRPs) are histone chaperons involved in nucleosome turnover. Despite this basic cellular function, the Arabidopsis nrp1-1 nrp2-1 knock out mutant has been reported to exhibit only mild seedling root phenotypes and to significantly affect the expression of only few hundred genes Zhu et al. (2006). Here we report that NRP loss-of-function as well as the ectopic overexpression of At NRP1 significantly affected the growth, development, and the pathogen response of Arabidopsis plants under short day conditions...
February 2018: Plant Science: An International Journal of Experimental Plant Biology
Nur Zafirah Zaidan, Kolin J Walker, Jaime E Brown, Leah V Schaffer, Mark Scalf, Michael R Shortreed, Gopal Iyer, Lloyd M Smith, Rupa Sridharan
The heterochromatin protein 1 (HP1) family is involved in various functions with maintenance of chromatin structure. During murine somatic cell reprogramming, we find that early depletion of HP1γ reduces the generation of induced pluripotent stem cells, while late depletion enhances the process, with a concomitant change from a centromeric to nucleoplasmic localization and elongation-associated histone H3.3 enrichment. Depletion of heterochromatin anchoring protein SENP7 increased reprogramming efficiency to a similar extent as HP1γ, indicating the importance of HP1γ release from chromatin for pluripotency acquisition...
January 17, 2018: Stem Cell Reports
Soyun Lee, Seunghee Oh, Kwiwan Jeong, Hyelim Jo, Yoonjung Choi, Hogyu David Seo, Minhoo Kim, Joonho Choe, Chang Seob Kwon, Daeyoup Lee
Dot1 (disruptor of telomeric silencing-1, DOT1L in humans) is the only known enzyme responsible for histone H3 lysine 79 methylation (H3K79me) and is evolutionarily conserved in most eukaryotes. Yeast Dot1p lacks a SET domain and does not methylate free histones and thus may have different actions with respect to other histone methyltransferases. Here we show that Dot1p displays histone chaperone activity and regulates nucleosome dynamics via histone exchange in yeast. We show that a methylation-independent function of Dot1p is required for the cryptic transcription within transcribed regions seen following disruption of the Set2-Rpd3S pathway...
January 16, 2018: Nature Communications
Elimelech Nesher, Alfiya Safina, Ieman Aljahdali, Scott Portwood, Eunice S Wang, Igor Koman, Jianmin Wang, Katerina V Gurova
Precisely how DNA-targeting chemotherapeutic drugs trigger cancer cell death remains unclear, as it is difficult to separate direct DNA damage from chromatin damage in cells. Recent work on curaxins, a class of small molecule drugs with broad anticancer activity, show that they interfere with histone-DNA interactions and destabilize nucleosomes without binding DNA or causing detectable DNA damage. Chromatin unfolding caused by curaxins is sensed by the histone chaperone FACT, which binds unfolded nucleosomes and causes chromatin trapping (c-trapping)...
January 16, 2018: Cancer Research
Alexander Pfab, Matthias Breindl, Klaus D Grasser
The histone chaperone FACT is involved in the expression of genes encoding anthocyanin biosynthetic enzymes also upon induction by moderate high-light and therefore contributes to the stress-induced plant pigmentation. The histone chaperone FACT consists of the SSRP1 and SPT16 proteins and associates with transcribing RNAPII (RNAPII) along the transcribed region of genes. FACT can promote transcriptional elongation by destabilising nucleosomes in the path of RNA polymerase II, thereby facilitating efficient transcription of chromatin templates...
January 13, 2018: Plant Molecular Biology
Delphine Quénet
In eukaryotes, the genome is organized into a complex nucleoprotein structure called chromatin. Despite the simplicity of its monomer, DNA and two copies of four histones, the existence of histone variants opens possibilities of multiple chromatin landscapes and fine-tune regulation of molecular mechanisms for the regulation of gene expression and maintenance of genome stability. However, any defects in these combinations may contribute to disease development and/or progression. Here, I review human histone variants and their chaperones, and discuss how they contribute to pathological conditions...
2018: International Review of Cell and Molecular Biology
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