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 In Vivo Study of the Nucleosome Assembly Functions of ASF1 Histone Chaperones in Human Cells

2008 ◽  
Vol 28 (11) ◽  
pp. 3672-3685 ◽  
Author(s):  
Angélique Galvani ◽  
Régis Courbeyrette ◽  
Morgane Agez ◽  
Françoise Ochsenbein ◽  
Carl Mann ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Histone H3 ◽  
Direct Determination ◽  
Human Cells ◽  
Chromatin Assembly ◽  
Histone Chaperones ◽  
Nucleosome Assembly ◽  
Assembly Factor

ABSTRACT Histone chaperones have been implicated in nucleosome assembly and disassembly as well as histone modification. ASF1 is a highly conserved histone H3/H4 chaperone that synergizes in vitro with two other histone chaperones, chromatin assembly factor 1 (CAF-1) and histone repression A factor (HIRA), in DNA synthesis-coupled and DNA synthesis-independent nucleosome assembly. Here, we identify mutants of histones H3.1 and H3.3 that are unable to interact with human ASF1A and ASF1B isoforms but that are still competent to bind CAF-1 and HIRA, respectively. We show that these mutant histones are inefficiently deposited into chromatin in vivo. Furthermore, we found that both ASF1A and ASF1B participate in the DNA synthesis-independent deposition of H3.3 in HeLa cells, thus highlighting an unexpected role for ASF1B in this pathway. This pathway does not require interaction of ASF1 with HIRA. We provide the first direct determination that ASF1A and ASF1B play a role in the efficiency of nucleosome assembly in vivo in human cells.

scholarly journals Two factor authentication: Asf1 mediates crosstalk between H3 K14 and K56 acetylation

2019 ◽  
Vol 47 (14) ◽  
pp. 7380-7391 ◽  
Author(s):  
Joy M Cote ◽  
Yin-Ming Kuo ◽  
Ryan A Henry ◽  
Hataichanok Scherman ◽  
Daniel D Krzizike ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Histone Acetylation ◽  
Histone H3 ◽  
Histone Chaperone ◽  
Biochemical Data ◽  
Genome Replication ◽  
Histone Chaperones ◽  
Post Translational Modifications ◽  
Lysine Acetyltransferase

Abstract The ability of histone chaperone Anti-silencing factor 1 (Asf1) to direct acetylation of lysine 56 of histone H3 (H3K56ac) represents an important regulatory step in genome replication and DNA repair. In Saccharomyces cerevisiae, Asf1 interacts functionally with a second chaperone, Vps75, and the lysine acetyltransferase (KAT) Rtt109. Both Asf1 and Vps75 can increase the specificity of histone acetylation by Rtt109, but neither alter selectivity. However, changes in acetylation selectivity have been observed in histones extracted from cells, which contain a plethora of post-translational modifications. In the present study, we use a series of singly acetylated histones to test the hypothesis that histone pre-acetylation and histone chaperones function together to drive preferential acetylation of H3K56. We show that pre-acetylated H3K14ac/H4 functions with Asf1 to drive specific acetylation of H3K56 by Rtt109–Vps75. Additionally, we identified an exosite containing an acidic patch in Asf1 and show that mutations to this region alter Asf1-mediated crosstalk that changes Rtt109–Vps75 selectivity. Our proposed mechanism suggests that Gcn5 acetylates H3K14, recruiting remodeler complexes, allowing for the Asf1-H3K14ac/H4 complex to be acetylated at H3K56 by Rtt109–Vps75. This mechanism explains the conflicting biochemical data and the genetic links between Rtt109, Vps75, Gcn5 and Asf1 in the acetylation of H3K56.

scholarly journals The histone chaperoning pathway: from ribosome to nucleosome

2019 ◽  
Vol 63 (1) ◽  
pp. 29-43 ◽  
Author(s):  
Alonso J. Pardal ◽  
Filipe Fernandes-Duarte ◽  
Andrew J. Bowman
Keyword(s):  
Supply And Demand ◽  
Histone Chaperone ◽  
Histone Chaperones ◽  
Post Translational Modifications ◽  
Core Histones ◽  
Eukaryotic Dna ◽  
Chaperone Interactions ◽  
Almost All ◽  
Chromatin Biology ◽  
Cellular Components

AbstractNucleosomes represent the fundamental repeating unit of eukaryotic DNA, and comprise eight core histones around which DNA is wrapped in nearly two superhelical turns. Histones do not have the intrinsic ability to form nucleosomes; rather, they require an extensive repertoire of interacting proteins collectively known as ‘histone chaperones’. At a fundamental level, it is believed that histone chaperones guide the assembly of nucleosomes through preventing non-productive charge-based aggregates between the basic histones and acidic cellular components. At a broader level, histone chaperones influence almost all aspects of chromatin biology, regulating histone supply and demand, governing histone variant deposition, maintaining functional chromatin domains and being co-factors for histone post-translational modifications, to name a few. In this essay we review recent structural insights into histone-chaperone interactions, explore evidence for the existence of a histone chaperoning ‘pathway’ and reconcile how such histone-chaperone interactions may function thermodynamically to assemble nucleosomes and maintain chromatin homeostasis.

scholarly journals Distinct histone H3–H4 binding modes of sNASP reveal the basis for cooperation and competition of histone chaperones

2021 ◽  
Author(s):  
Chao-Pei Liu ◽  
Wenxing Jin ◽  
Jie Hu ◽  
Mingzhu Wang ◽  
Jingjing Chen ◽  
...  
Keyword(s):  
De Novo ◽  
Critical Role ◽  
Histone H3 ◽  
Coiled Coil ◽  
Dynamic Network ◽  
Histone Chaperones ◽  
Binding Modes ◽  
Nucleosome Assembly ◽  
Partially Unfolded

Chromosomal duplication requires de novo assembly of nucleosomes from newly synthesized histones, and the process involves a dynamic network of interactions between histones and histone chaperones. sNASP and ASF1 are two major histone H3–H4 chaperones found in distinct and common complexes, yet how sNASP binds H3–H4 in the presence and absence of ASF1 remains unclear. Here we show that, in the presence of ASF1, sNASP principally recognizes a partially unfolded Nα region of histone H3, and in the absence of ASF1, an additional sNASP binding site becomes available in the core domain of the H3–H4 complex. Our study also implicates a critical role of the C-terminal tail of H4 in the transfer of H3–H4 between sNASP and ASF1 and the coiled-coil domain of sNASP in nucleosome assembly. These findings provide mechanistic insights into coordinated histone binding and transfer by histone chaperones.

scholarly journals The Carboxyl Terminus of Rtt109 Functions in Chaperone Control of Histone Acetylation

2013 ◽  
Vol 12 (5) ◽  
pp. 654-664 ◽  
Author(s):  
Ernest Radovani ◽  
Matthew Cadorin ◽  
Tahireh Shams ◽  
Suzan El-Rass ◽  
Abdel R. Karsou ◽  
...  
Keyword(s):  
Histone Acetyltransferase ◽  
Histone H3 ◽  
Chromatin Assembly ◽  
Carboxyl Terminus ◽  
Histone Chaperones ◽  
Content Type ◽  
Histone H3 Acetylation ◽  
H3 Acetylation

ABSTRACT Rtt109 is a fungal histone acetyltransferase (HAT) that catalyzes histone H3 acetylation functionally associated with chromatin assembly. Rtt109-mediated H3 acetylation involves two histone chaperones, Asf1 and Vps75. In vivo , Rtt109 requires both chaperones for histone H3 lysine 9 acetylation (H3K9ac) but only Asf1 for full H3K56ac. In vitro , Rtt109-Vps75 catalyzes both H3K9ac and H3K56ac, whereas Rtt109-Asf1 catalyzes only H3K56ac. In this study, we extend the in vitro chaperone-associated substrate specificity of Rtt109 by showing that it acetylates vertebrate linker histone in the presence of Vps75 but not Asf1. In addition, we demonstrate that in Saccharomyces cerevisiae a short basic sequence at the carboxyl terminus of Rtt109 (Rtt109C) is required for H3K9ac in vivo . Furthermore, through in vitro and in vivo studies, we demonstrate that Rtt109C is required for optimal H3K56ac by the HAT in the presence of full-length Asf1. When Rtt109C is absent, Vps75 becomes important for H3K56ac by Rtt109 in vivo . In addition, we show that lysine 290 (K290) in Rtt109 is required in vivo for Vps75 to enhance the activity of the HAT. This is the first in vivo evidence for a role for Vps75 in H3K56ac. Taken together, our results contribute to a better understanding of chaperone control of Rtt109-mediated H3 acetylation.

scholarly journals Nucleosome composition regulates the histone H3 tail conformational ensemble and accessibility

2020 ◽  
Author(s):  
Emma A. Morrison ◽  
Lokesh Baweja ◽  
Michael G. Poirier ◽  
Jeff Wereszczynski ◽  
Catherine A. Musselman
Keyword(s):  
Rna Polymerase Ii ◽  
Conformational Dynamics ◽  
Md Simulations ◽  
Conformational Ensemble ◽  
Histone Chaperones ◽  
Dna Dynamics ◽  
Nucleosome Assembly ◽  
Regulatory Factor ◽  
Histone Tails ◽  
Nucleosomal Dna

AbstractSub-nucleosomal complexes including hexasomes and tetrasomes have been identified as intermediates in nucleosome assembly and disassembly. Their formation is promoted by certain histone chaperones and ATP-dependent remodelers, as well as through transcription by RNA polymerase II. In addition, hexasomes appear to be maintained in transcribed genes and could be an important regulatory factor. While nucleosome composition affects the structure and accessibility of the nucleosomal DNA, its influence on the histone tails is largely unknown. Previously, we found that the H3 tail accessibly is occluded in the context of the nucleosome due to interactions with DNA (Morrison et al, 2018). Here, we investigate the conformational dynamics of the H3 tail in the hexasome and tetrasome. Using a combination of NMR spectroscopy, MD simulations, and trypsin proteolysis, we find that the conformational ensemble of the H3 tail is regulated by nucleosome composition. Similar to what we previously found for the nucleosome, the H3 tails bind robustly to DNA within the hexasome and tetrasome, but upon loss of the H2A/H2B dimer, we determined that the adjacent H3 tail has an altered conformational ensemble, increase in dynamics, and increase in accessibility. Similar to observations of DNA dynamics, this is seen to be asymmetric in the hexasome. Our results indicate that nucleosome composition has the potential to regulate chromatin signaling at the histone tails and ultimately help shape the chromatin landscape.

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.

scholarly journals The Histone Chaperone Asf1p Mediates Global Chromatin Disassemblyin Vivo

2004 ◽  
Vol 279 (50) ◽  
pp. 52069-52074 ◽  
Author(s):  
Melissa W. Adkins ◽  
Jessica K. Tyler
Keyword(s):  
Histone Acetylation ◽  
Chromatin Structure ◽  
Histone H3 ◽  
Dnase I ◽  
Chromatin Assembly ◽  
Eukaryotic Genome ◽  
Micrococcal Nuclease ◽  
Histone Chaperones ◽  
Assembly Factor

The packaging of the eukaryotic genome into chromatin is likely to be mediated by chromatin assembly factors, including histone chaperones. We investigated the function of the histone H3/H4 chaperones anti-silencing function 1 (Asf1p) and chromatin assembly factor 1 (CAF-1)in vivo. Analysis of chromatin structure by accessibility to micrococcal nuclease and DNase I digestion demonstrated that the chromatin from CAF-1 mutant yeast has increased accessibility to these enzymes. In agreement, the supercoiling of the endogenous 2μ plasmid is reduced in yeast lacking CAF-1. These results indicate that CAF-1 mutant yeast globally under-assemble their genome into chromatin, consistent with a role for CAF-1 in chromatin assemblyin vivo. By contrast,asf1mutants globally over-assemble their genome into chromatin, as suggested by decreased accessibility of their chromatin to micrococcal nuclease and DNase I digestion and increased supercoiling of the endogenous 2μ plasmid. Deletion ofASF1causes a striking loss of acetylation on histone H3 lysine 9, but this is not responsible for the altered chromatin structure inasf1mutants. These data indicate that Asf1p may have a global role in chromatin disassembly and an unexpected role in histone acetylationin vivo.

scholarly journals Chromatin assembly: Journey to the CENter of the chromosome

2016 ◽  
Vol 214 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Chin-Chi Chen ◽  
Barbara G. Mellone
Keyword(s):  
Cell Survival ◽  
Histone H3 ◽  
Chromatin Assembly ◽  
Nucleosome Assembly ◽  
Histone Proteins ◽  
Chromatin Domains ◽  
Histone H3 Variant ◽  
Distinctive Type ◽  
Eukaryotic Genomes

All eukaryotic genomes are packaged into basic units of DNA wrapped around histone proteins called nucleosomes. The ability of histones to specify a variety of epigenetic states at defined chromatin domains is essential for cell survival. The most distinctive type of chromatin is found at centromeres, which are marked by the centromere-specific histone H3 variant CENP-A. Many of the factors that regulate CENP-A chromatin have been identified; however, our understanding of the mechanisms of centromeric nucleosome assembly, maintenance, and reorganization remains limited. This review discusses recent insights into these processes and draws parallels between centromeric and noncentromeric chromatin assembly mechanisms.

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