scholarly journals Wie das Histon-Chaperon FACT aktives und stilles Chromatin bewahrt

BIOspektrum ◽  
2021 ◽  
Vol 27 (3) ◽  
pp. 265-268
Author(s):  
Magdalena Murawska ◽  
Andreas G. Ladurner
Keyword(s):  
Histone Chaperone ◽  
Histone Chaperones ◽  
Histone Proteins ◽  
Genome Dynamics ◽  
Chaperone Complex

AbstractHistone chaperones play a fundamental role in the regulation of genome dynamics and stability. They are a versatile group of proteins that interact with histone proteins and govern their assembly or disassembly into nucleosomes. How the activity of histone chaperones is regulated is not well understood. Here, we discuss our new data on how histone post-transcriptional modifications cooperate with the essential histone chaperone complex FACT in active and silent regions of the genome.

scholarly journals NASP maintains histone H3–H4 homeostasis through two distinct H3 binding modes

2021 ◽  
Author(s):  
Hongyu Bao ◽  
Massimo Carraro ◽  
Valentin Flury ◽  
Yanhong Liu ◽  
Min Luo ◽  
...  
Keyword(s):  
Histone H3 ◽  
Histone Chaperone ◽  
Histone Chaperones ◽  
Binding Modes ◽  
Histone Binding ◽  
Chaperone Complex

Histone chaperones regulate all aspects of histone metabolism. NASP is a major histone chaperone for H3–H4 dimers critical for preventing histone degradation.Here, we identify two distinct histone binding modes of NASP and reveal how they cooperate to ensure histone H3–H4 supply. We determine the structures of a sNASP dimer, a complex of sNASP with an H3 α3 peptide, and the sNASP–H3–H4–ASF1b co-chaperone complex.

scholarly journals Histone transfer among chaperones

2012 ◽  
Vol 40 (2) ◽  
pp. 357-363 ◽  
Author(s):  
Wallace H. Liu ◽  
Mair E.A. Churchill
Keyword(s):  
Histone H3 ◽  
Histone Chaperone ◽  
Chromatin Assembly ◽  
Histone Chaperones ◽  
Nucleosome Assembly ◽  
Post Translational Modifications ◽  
Chromatin Dynamics ◽  
Nucleosomal Dna ◽  
Chaperone Interactions ◽  
Dependent Processes

The eukaryotic processes of nucleosome assembly and disassembly govern chromatin dynamics, in which histones exchange in a highly regulated manner to promote genome accessibility for all DNA-dependent processes. This regulation is partly carried out by histone chaperones, which serve multifaceted roles in co-ordinating the interactions of histone proteins with modification enzymes, nucleosome remodellers, other histone chaperones and nucleosomal DNA. The molecular details of the processes by which histone chaperones promote delivery of histones among their many functional partners are still largely undefined, but promise to offer insights into epigenome maintenance. In the present paper, we review recent findings on the histone chaperone interactions that guide the assembly of histones H3 and H4 into chromatin. This evidence supports the concepts of histone post-translational modifications and specific histone chaperone interactions as guiding principles for histone H3/H4 transactions during chromatin assembly.

scholarly journals A Genome-Wide Screen Reveals a Role for the HIR Histone Chaperone Complex in Preventing Mislocalization of Budding Yeast CENP-A

Genetics ◽  
2018 ◽  
Vol 210 (1) ◽  
pp. 203-218 ◽  
Author(s):  
Sultan Ciftci-Yilmaz ◽  
Wei-Chun Au ◽  
Prashant K. Mishra ◽  
Jessica R. Eisenstatt ◽  
Joy Chang ◽  
...  
Keyword(s):  
Budding Yeast ◽  
Histone Chaperone ◽  
Genome Wide ◽  
A Genome ◽  
Chaperone Complex

scholarly journals Histone chaperones exhibit conserved functionality in nucleosome remodeling

2022 ◽  
Author(s):  
Pedro Buzon ◽  
Alejandro Velazquez-Cruz ◽  
Katiuska Gonzalez-Arzola ◽  
Antonio Diaz-Quintana ◽  
Irene Diaz-Moreno ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Molecular Level ◽  
Eukaryotic Cell ◽  
Histone Chaperone ◽  
Histone Chaperones ◽  
Dynamic Nature ◽  
Nucleosome Remodeling ◽  
Molecular Action ◽  
Core Histones

Chromatin homeostasis mediates some of the most fundamental processes in the eukaryotic cell. In this regard, histone chaperones have emerged as major regulatory factors during DNA replication, repair, and transcription. However, the dynamic nature of these processes has severely impeded their characterization at the molecular level. Here we apply single-molecule probing by fluorescence optical tweezers to follow histone chaperone dynamics in real-time. The molecular action of SET/template-activating factor-Iβ and nucleophosmin 1, representing the two most common histone chaperone folds, were examined using both nucleosomes and isolated core histones. We show that these chaperones present binding specificity for partially dismantled nucleosomes and are able to recognize and disrupt non-native histone-DNA interactions. Furthermore, we reveal that cytochrome c inhibition of histone chaperones is coupled to chaperone accumulation on DNA-bound histones. Our single-molecule approach shows that despite the drastically different structures of these chaperones, they present conserved modes of action mediating nucleosome remodeling.

scholarly journals Disruption of NAP1 genes supresses the fas1 mutant phenotype and enhances genome stability

2020 ◽  
Author(s):  
Karolína Kolářová ◽  
Martina Nešpor Dadejová ◽  
Tomáš Loja ◽  
Eva Sýkorová ◽  
Martina Dvořáčková
Keyword(s):  
Genome Stability ◽  
Genetic Interaction ◽  
Plant Morphology ◽  
Genotoxic Stress ◽  
Histone Chaperone ◽  
Micrococcal Nuclease ◽  
Molecular Networks ◽  
Histone Chaperones ◽  
Loss Of Function ◽  
Nucleosome Assembly

ABSTRACTHistone chaperones mediate assembly and disassembly of nucleosomes and participate in essentially all DNA-dependent cellular processes. In Arabidopsis thaliana, loss-of-functions of FAS1 or FAS2 subunits of the H3-H4 histone chaperone complex CHROMATIN ASSEMBLY FACTOR 1(CAF-1) has a dramatic effect on plant morphology, growth and overall fitness. Altered chromatin compaction, systematic loss of repetitive elements or increased DNA damage clearly demonstrate the severity of CAF-1 dysfunction. How histone chaperone molecular networks change without a functional CAF-1 remains elusive. Here we present an intriguing observation that disruption of the H2A-H2B histone chaperone NUCLEOSOME ASSEMBLY PROTEIN 1 (NAP1) supresses FAS1 loss-of function. The quadruple mutant fas1nap1;1-3 shows wild-type growth and decreased sensitivity to genotoxic stress. Chromatin of fas1nap1;1-3 plants is less accessible to micrococcal nuclease and progressive loss of telomeres and 45S rDNA is supressed. Interestingly, the strong genetic interaction between FAS1 and NAP1 does not occur via direct protein-protein interaction. We propose that NAP1;1-3 play an essential role in nucleosome assembly in fas1, thus their disruption abolishes fas1 defects. Our data altogether reveal a novel function of NAP1 proteins, unmasked by CAF-1 dysfunction. It emphasizes the importance of a balanced composition of chromatin and shed light on the histone chaperone molecular network.

scholarly journals Histone chaperone FACT represses retrotransposon MERVL and MERVL-derived cryptic promoters

2020 ◽  
Vol 48 (18) ◽  
pp. 10211-10225 ◽  
Author(s):  
Fuquan Chen ◽  
Weiyu Zhang ◽  
Dan Xie ◽  
Tingting Gao ◽  
Zhiqiang Dong ◽  
...  
Keyword(s):  
Target Genes ◽  
Critical Role ◽  
Histone H3 ◽  
Embryonic Stem ◽  
Histone Chaperone ◽  
Endogenous Retroviruses ◽  
Histone Chaperones ◽  
Cryptic Transcription ◽  
Unique Mechanism ◽  
Cryptic Promoters

Abstract Endogenous retroviruses (ERVs) were usually silenced by various histone modifications on histone H3 variants and respective histone chaperones in embryonic stem cells (ESCs). However, it is still unknown whether chaperones of other histones could repress ERVs. Here, we show that H2A/H2B histone chaperone FACT plays a critical role in silencing ERVs and ERV-derived cryptic promoters in ESCs. Loss of FACT component Ssrp1 activated MERVL whereas the re-introduction of Ssrp1 rescued the phenotype. Additionally, Ssrp1 interacted with MERVL and suppressed cryptic transcription of MERVL-fused genes. Remarkably, Ssrp1 interacted with and recruited H2B deubiquitinase Usp7 to Ssrp1 target genes. Suppression of Usp7 caused similar phenotypes as loss of Ssrp1. Furthermore, Usp7 acted by deubiquitinating H2Bub and thereby repressed the expression of MERVL-fused genes. Taken together, our study uncovers a unique mechanism by which FACT complex silences ERVs and ERV-derived cryptic promoters in ESCs.

H3–H4 Histone Chaperone Pathways

2018 ◽  
Vol 52 (1) ◽  
pp. 109-130 ◽  
Author(s):  
Prerna Grover ◽  
Jonathon S. Asa ◽  
Eric I. Campos
Keyword(s):  
Posttranslational Modifications ◽  
Nuclear Import ◽  
Genetic Material ◽  
Histone Variants ◽  
Chromatin Accessibility ◽  
Histone Chaperone ◽  
Structural Level ◽  
Histone Chaperones ◽  
Dynamic Nature ◽  
Histone Deposition

Nucleosomes compact and organize genetic material on a structural level. However, they also alter local chromatin accessibility through changes in their position, through the incorporation of histone variants, and through a vast array of histone posttranslational modifications. The dynamic nature of chromatin requires histone chaperones to process, deposit, and evict histones in different tissues and at different times in the cell cycle. This review focuses on the molecular details of canonical and variant H3–H4 histone chaperone pathways that lead to histone deposition on DNA as they are currently understood. Emphasis is placed on the most established pathways beginning with the folding, posttranslational modification, and nuclear import of newly synthesized H3–H4 histones. Next, we review the deposition of replication-coupled H3.1–H4 in S-phase and replication-independent H3.3–H4 via alternative histone chaperone pathways. Highly specialized histone chaperones overseeing the deposition of histone variants are also briefly discussed.

scholarly journals Coordinated Action of Nap1 and RSC in Disassembly of Tandem Nucleosomes

2016 ◽  
Vol 36 (17) ◽  
pp. 2262-2271 ◽  
Author(s):  
Rashmi Prasad ◽  
Sheena D'Arcy ◽  
Arjan Hada ◽  
Karolin Luger ◽  
Blaine Bartholomew
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mutational Analysis ◽  
Histone Chaperone ◽  
Histone Chaperones ◽  
Content Type ◽  
Chromatin Remodelers ◽  
Coordinated Action

The SWI/SNF and RSC family of ATP-dependent chromatin remodelers disassembles nucleosomes by moving nucleosomes into the vicinity of adjoining nucleosomes. We found that the histone chaperone Nap1 efficiently promotes disassembly of adjacent nucleosomes with which RSC collides and not the disassembly of nucleosomes mobilized by RSC. Nap1 is specific to RSC, as it does not target SWI/SNF, its paralog inSaccharomyces cerevisiae. Extensive mutational analysis of Nap1 has revealed that Nap1 affinity for histones H2A-H2B and H3-H4 and its ability to displace histones from DNA are required for Nap1 to enhance RSC-mediated disassembly. Other histone chaperones, such as Vps75, that also bind histones are not able to enhance RSC-mediated disassembly. Our study suggests a mechanism by which Nap1 is recruited to actively transcribed regions and assists in the passage of the transcription complex through chromatin, and it provides a novel mechanism for the coordinated action of RSC and Nap1.

scholarly journals The histone chaperone Nrp1 is required for chromatin stability and nuclear division in Tetrahymena thermophila

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yinjie Lian ◽  
Huijuan Hao ◽  
Jing Xu ◽  
Tao Bo ◽  
Aihua Liang ◽  
...  
Keyword(s):  
Developmental Stage ◽  
Vegetative Growth ◽  
Growth Stage ◽  
Cellular Proliferation ◽  
Nuclear Division ◽  
Tetrahymena Thermophila ◽  
Affinity Purification ◽  
Histone Chaperone ◽  
Mass Spectrometry Analysis ◽  
Histone Chaperones

AbstractHistone chaperones facilitate DNA replication and repair by promoting chromatin assembly, disassembly and histone exchange. Following histones synthesis and nucleosome assembly, the histones undergo posttranslational modification by different enzymes and are deposited onto chromatins by various histone chaperones. In Tetrahymena thermophila, histones from macronucleus (MAC) and micronucleus (MIC) have been comprehensively investigated, but the function of histone chaperones remains unclear. Histone chaperone Nrp1 in Tetrahymena contains four conserved tetratricopepeptide repeat (TPR) domains and one C-terminal nuclear localization signal. TPR2 is typically interrupted by a large acidic motif. Immunofluorescence staining showed that Nrp1 is located in the MAC and MICs, but disappeared in the apoptotic parental MAC and the degraded MICs during the conjugation stage. Nrp1 was also colocalized with α-tubulin around the spindle structure. NRP1 knockdown inhibited cellular proliferation and led to the loss of chromosome, abnormal macronuclear amitosis, and disorganized micronuclear mitosis during the vegetative growth stage. During sexual developmental stage, the gametic nuclei failed to be selected and abnormally degraded in NRP1 knockdown mutants. Affinity purification combined with mass spectrometry analysis indicated that Nrp1 is co-purified with core histones, heat shock proteins, histone chaperones, and DNA damage repair proteins. The physical direct interaction of Nrp1 and Asf1 was also confirmed by pull-down analysis in vitro. The results show that histone chaperone Nrp1 is involved in micronuclear mitosis and macronuclear amitosis in the vegetative growth stage and maintains gametic nuclei formation during the sexual developmental stage. Nrp1 is required for chromatin stability and nuclear division in Tetrahymena thermophila.

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