Connection between histone H2A variants and chromatin remodeling complexesThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB’s 51st Annual Meeting – Epigenetics and Chromatin Dynamics, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 87 (1) ◽  
pp. 35-50 ◽  
Author(s):  
Mohammed Altaf ◽  
Andréanne Auger ◽  
Marcela Covic ◽  
Jacques Côté
Keyword(s):  
Chromatin Remodeling ◽  
Chromatin Structure ◽  
Cellular Response ◽  
Peer Review Process ◽  
Histone Variants ◽  
Histone H2a ◽  
Chromatin Dynamics ◽  
Recent Developments ◽  
Chromatin Remodeling Complexes ◽  
And Function

The organization of the eukaryotic genome into chromatin makes it inaccessible to the factors required for gene transcription and DNA replication, recombination, and repair. In addition to histone-modifying enzymes and ATP-dependent chromatin remodeling complexes, which play key roles in regulating many nuclear processes by altering the chromatin structure, cells have developed a mechanism of modulating chromatin structure by incorporating histone variants. These variants are incorporated into specific regions of the genome throughout the cell cycle. H2A.Z, which is an evolutionarily conserved H2A variant, performs several seemingly unrelated and even contrary functions. Another H2A variant, H2A.X, plays a very important role in the cellular response to DNA damage. This review summarizes the recent developments in our understanding of the role of H2A.Z and H2A.X in the regulation of chromatin structure and function, focusing on their functional links with chromatin modifying and remodeling complexes.

H2AX: tailoring histone H2A for chromatin-dependent genomic integrity

2005 ◽  
Vol 83 (4) ◽  
pp. 505-515 ◽  
Author(s):  
Andra Li ◽  
José M Eirín-López ◽  
Juan Ausió
Keyword(s):  
Chromatin Structure ◽  
Histone Variants ◽  
Environmental Damage ◽  
Structural Level ◽  
Histone H2a ◽  
Dna Breaks ◽  
Histone H2ax ◽  
Double Stranded Dna ◽  
Chromatin Remodeling Complexes ◽  
And Function

During the last decade, chromatin research has been focusing on the role of histone variability as a modulator of chromatin structure and function. Histone variability can be the result of either post-translational modifications or intrinsic variation at the primary structure level: histone variants. In this review, we center our attention on one of the most extensively characterized of such histone variants in recent years, histone H2AX. The molecular phylogeny of this variant seems to have run in parallel with that of the major canonical somatic H2A1 in eukaryotes. Functionally, H2AX appears to be mainly associated with maintaining the genome integrity by participating in the repair of the double-stranded DNA breaks exogenously introduced by environmental damage (ionizing radiation, chemicals) or in the process of homologous recombination during meiosis. At the structural level, these processes involve the phosphorylation of serine at the SQE motif, which is present at the very end of the C-terminal domain of H2AX, and possibly other PTMs, some of which have recently started to be defined. We discuss a model to account for how these H2AX PTMs in conjunction with chromatin remodeling complexes (such as INO80 and SWRI) can modify chromatin structure (remodeling) to support the DNA unraveling ultimately required for DNA repair.Key words: H2AX, DNA repair, double-stranded DNA breaks, phosphorylation.

New developments in post-translational modifications and functions of histone H2A variantsThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB’s 51st Annual Meeting – Epigenetics and Chromatin Dynamics, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 87 (1) ◽  
pp. 7-17 ◽  
Author(s):  
Anita A. Thambirajah ◽  
Andra Li ◽  
Toyotaka Ishibashi ◽  
Juan Ausió
Keyword(s):  
Review Process ◽  
Peer Review Process ◽  
Histone Variants ◽  
Histone H2a ◽  
Post Translational Modifications ◽  
New Developments ◽  
Chromatin Dynamics ◽  
Recent Developments ◽  
The Individual ◽  
Selection Of

Structural variability within histone families, such as H2A, can be achieved through 2 primary mechanisms: the expression of histone variants and the incorporation of chemical modifications. The histone H2A family contains several variants in addition to the canonical H2A forms. In this review, recent developments in the study of the heteromorphous variants H2A.X, H2A.Z, and macroH2A will be discussed. Particular focus will be given to the post-translational modifications (PTMs) of these variants, including phosphorylation, ubiquitination, acetylation, and methylation. The combination of the newly identified N- and C-terminal tail PTMs expands the multiplicity of roles that the individual H2A variants can perform. It is of additional interest that analogous sites within these different histone variants can be similarly modified. Whether this is a redundant function or a finely tuned one, designed to meet specific needs, remains to be elucidated.

The molecular basis of chromatin dynamics during nucleotide excision repairThis paper is one of a selection of papers published in this Special Issue, entitled 29th Annual International Asilomar Chromatin and Chromosomes Conference, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 87 (1) ◽  
pp. 265-272 ◽  
Author(s):  
Ling Zhang ◽  
Kristi Jones ◽  
Feng Gong
Keyword(s):  
Chromatin Remodeling ◽  
Molecular Basis ◽  
Excision Repair ◽  
Peer Review Process ◽  
Critical Role ◽  
Chromatin Dynamics ◽  
Nucleotide Excision ◽  
Chromatin Remodeling Complexes

The assembly of DNA into chromatin in eukaryotic cells affects all DNA-related cellular activities, such as replication, transcription, recombination, and repair. Rearrangement of chromatin structure during nucleotide excision repair (NER) was discovered more than 2 decades ago. However, the molecular basis of chromatin dynamics during NER remains undefined. Pioneering studies in the field of gene transcription have shown that ATP-dependent chromatin-remodeling complexes and histone-modifying enzymes play a critical role in chromatin dynamics during transcription. Similarly, recent studies have demonstrated that the SWI/SNF chromatin-remodeling complex facilitates NER both in vitro and in vivo. Additionally, histone acetylation has also been linked to the NER of ultraviolet light damage. In this article, we will discuss the role of these identified chromatin-modifying activities in NER.

Mechanistic and structural insights into histone H2A–H2B chaperone in chromatin regulation

2020 ◽  
Vol 477 (17) ◽  
pp. 3367-3386
Author(s):  
Yan Huang ◽  
Yaxin Dai ◽  
Zheng Zhou
Keyword(s):  
Chromatin Remodeling ◽  
Chromatin Structure ◽  
Current Knowledge ◽  
Histone Variants ◽  
Functional Study ◽  
Histone Chaperones ◽  
Chromatin Regulation ◽  
Histone H2a ◽  
Chromatin Remodeling Complex ◽  
Recent Advances

Histone chaperones include a wide variety of proteins which associate with histones and regulate chromatin structure. The classic H2A–H2B type of histone chaperones, and the chromatin remodeling complex components possessing H2A–H2B chaperone activity, show a broad range of structures and functions. Rapid progress in the structural and functional study of H2A–H2B chaperones extends our knowledge about the epigenetic regulation of chromatin. In this review, we summarize the most recent advances in the understanding of the structure and function of H2A–H2B chaperones that interact with either canonical or variant H2A–H2B dimers. We discuss the current knowledge of the H2A–H2B chaperones, which present no preference for canonical and variant H2A–H2B dimers, describing how they interact with H2A–H2B to fulfill their functions. We also review recent advances of H2A variant-specific chaperones, demarcating how they achieve specific recognition for histone variant H2A.Z and how these interactions regulate chromatin structure by nucleosome editing. We highlight the universal mechanism underlying H2A–H2B dimers recognition by a large variety of histone chaperones. These findings will shed insight into the biological impacts of histone chaperone, chromatin remodeling complex, and histone variants in chromatin regulation.

scholarly journals Chromatin Enrichment for Proteomics in Plants (ChEP-P) Implicates the Histone Reader ALFIN-LIKE 6 in Jasmonate Signalling

2021 ◽  
Author(s):  
Isabel Cristina Vélez-Bermúdez ◽  
Wolfgang Schmidt
Keyword(s):  
Histone Variants ◽  
Homeodomain Protein ◽  
Chromatin Dynamics ◽  
Histone 3 ◽  
Plant Homeodomain ◽  
Associated Proteins ◽  
Bona Fide ◽  
Covalent Modifications ◽  
And Function

Abstract BackgroundCovalent modifications of core histonesgoverndownstream DNA-templated processes such as transcription by altering chromatin structure and function. Previously, we reported that the plant homeodomain protein ALFIN-LIKE6 (AL6), a bona fide histone reader that preferentially binds trimethylated lysin 4 on histone 3 (H3K4me3), is critical for recalibration of cellular phosphate (Pi) homeostasis and root hair elongation under Pi-deficient conditions. ResultsHere, we demonstrate that AL6 is also involved in the response of Arabidopsis seedlings to jasmonic acid (JA) during skotomorphogenesis, possibly by modulating chromatin dynamics that affect the transcriptional regulation of JA-responsivegenes. Dark-grown al6 seedlings showed a compromised reduction in hypocotyl elongation upon exogenously supplied JA, a response that was calibrated by the availability of Pi in the growth medium. A comparison of protein profiles between wild-type and al6 mutant seedlings using a quantitative Chromatin Enrichment for Proteomics (ChEP) approach,that we modified for plant tissue and designated ChEP-P (ChEP in Plants), yielded a comprehensive suite of chromatin-associated proteins and candidates that may be causative for the mutant phenotype. ConclusionsAltered abundance of proteins involved in chromatin organization in al6 seedlings suggests a role of AL6 in coordinating the deposition of histone variants upon perception of internal or environmental stimuli. Our study shows that ChEP-P is well suited to gain holistic insights into chromatin-related processes in plants. Data are available via ProteomeXchange with identifier PXD026541.

scholarly journals Plant Histone HTB (H2B) Variants in Regulating Chromatin Structure and Function

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1435
Author(s):  
Janardan Khadka ◽  
Anat Pesok ◽  
Gideon Grafi
Keyword(s):  
Arabidopsis Thaliana ◽  
Chromatin Structure ◽  
Developmental Stages ◽  
Histone Variants ◽  
Structure And Function ◽  
Core Histone ◽  
Histone H2b ◽  
Histone Proteins ◽  
Genes Encoding ◽  
And Function

Besides chemical modification of histone proteins, chromatin dynamics can be modulated by histone variants. Most organisms possess multiple genes encoding for core histone proteins, which are highly similar in amino acid sequence. The Arabidopsis thaliana genome contains 11 genes encoding for histone H2B (HTBs), 13 for H2A (HTAs), 15 for H3 (HTRs), and 8 genes encoding for histone H4 (HFOs). The finding that histone variants may be expressed in specific tissues and/or during specific developmental stages, often displaying specific nuclear localization and involvement in specific nuclear processes suggests that histone variants have evolved to carry out specific functions in regulating chromatin structure and function and might be important for better understanding of growth and development and particularly the response to stress. In this review, we will elaborate on a group of core histone proteins in Arabidopsis, namely histone H2B, summarize existing data, and illuminate the potential function of H2B variants in regulating chromatin structure and function in Arabidopsis thaliana.

Functional diversity of ISWI complexes

2004 ◽  
Vol 82 (4) ◽  
pp. 482-489 ◽  
Author(s):  
Sara S Dirscherl ◽  
Jocelyn E Krebs
Keyword(s):  
Chromatin Remodeling ◽  
Catalytic Core ◽  
Chromatin Remodelers ◽  
Form And Function ◽  
Curr Opin Cell Biol ◽  
Chromatid Cohesion ◽  
Chromatin Remodeling Complexes ◽  
And Function ◽  
Diverse Groups ◽  
Nuclear Processes

The yeast SWI/SNF ATP-dependent chromatin remodeling complex was first identified and characterized over 10 years ago (F. Winston and M. Carlson. 1992. Trends Genet. 8: 387–391.) Since then, the number of distinct ATP-dependent chromatin remodeling complexes and the variety of roles they play in nuclear processes have become dizzying (J.A. Martens and F. Winston. 2003. Curr. Opin. Genet. Dev. 13: 136–142; A. Vacquero et al. 2003. Sci. Aging Knowledge Environ. 2003: RE4) — and that does not even include the companion suite of histone modifying enzymes, which exhibit a comparable diversity in both number of complexes and variety of functions (M.J. Carrozza et al. 2003. Trends Genet. 19: 321–329; W. Fischle et al. 2003. Curr. Opin. Cell Biol. 15: 172–183; M. Iizuka and M.M. Smith. 2003. Curr. Opin. Genet. Dev. 13: 1529–1539). This vast complexity is hardly surprising, given that all nuclear processes that involve DNA — transcription, replication, repair, recombination, sister chromatid cohesion, etc. — must all occur in the context of chromatin. The SWI/SNF-related ATP-dependent remodelers are divided into a number of subfamilies, all related by the SWI2/SNF2 ATPase at their catalytic core. In nearly every species where researchers have looked for them, one or more members of each subfamily have been identified. Even the budding yeast, with its comparatively small genome, contains eight different chromatin remodelers in five different subfamilies. This review will focus on just one subfamily, the Imitation Switch (ISWI) family, which is proving to be one of the most diverse groups of chromatin remodelers in both form and function.

scholarly journals Widespread Collaboration of Isw2 and Sin3-Rpd3 Chromatin Remodeling Complexes in Transcriptional Repression

2001 ◽  
Vol 21 (19) ◽  
pp. 6450-6460 ◽  
Author(s):  
Thomas G. Fazzio ◽  
Charles Kooperberg ◽  
Jesse P. Goldmark ◽  
Cassandra Neal ◽  
Ryan Basom ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Chromatin Structure ◽  
Transcriptional Repression ◽  
Target Genes ◽  
Full Range ◽  
Dnase I ◽  
Genome Expression ◽  
Complex Functions ◽  
Dnase I Sensitivity ◽  
Chromatin Remodeling Complexes

ABSTRACT The yeast Isw2 chromatin remodeling complex functions in parallel with the Sin3-Rpd3 histone deacetylase complex to repress early meiotic genes upon recruitment by Ume6p. For many of these genes, the effect of an isw2 mutation is partially masked by a functional Sin3-Rpd3 complex. To identify the full range of genes repressed or activated by these factors and uncover hidden targets of Isw2-dependent regulation, we performed full genome expression analyses using cDNA microarrays. We find that the Isw2 complex functions mainly in repression of transcription in a parallel pathway with the Sin3-Rpd3 complex. In addition to Ume6 target genes, we find that many Ume6-independent genes are derepressed in mutants lacking functional Isw2 and Sin3-Rpd3 complexes. Conversely, we find thatume6 mutants, but not isw2 sin3 or isw2 rpd3 double mutants, have reduced fidelity of mitotic chromosome segregation, suggesting that one or more functions of Ume6p are independent of Sin3-Rpd3 and Isw2 complexes. Chromatin structure analyses of two nonmeiotic genes reveals increased DNase I sensitivity within their regulatory regions in an isw2 mutant, as seen previously for one meiotic locus. These data suggest that the Isw2 complex functions at Ume6-dependent and -independent loci to create DNase I-inaccessible chromatin structure by regulating the positioning or placement of nucleosomes.

NuA4 and SWR1-C: two chromatin-modifying complexes with overlapping functions and componentsThis paper is one of a selection of papers published in this Special Issue, entitled 30th Annual International Asilomar Chromatin and Chromosomes Conference, and has undergone the Journal's usual peer review process.

2009 ◽  
Vol 87 (5) ◽  
pp. 799-815 ◽  
Author(s):  
Phoebe Y.T. Lu ◽  
Nancy Lévesque ◽  
Michael S. Kobor
Keyword(s):  
Chromatin Structure ◽  
Protein Complexes ◽  
Peer Review Process ◽  
Histone Variant ◽  
Chromatin Remodelling ◽  
Cellular Processes ◽  
Evolutionarily Conserved ◽  
And Function ◽  
Histone Deposition ◽  
Chemical Groups

Chromatin structure is important for the compaction of eukaryotic genomes, thus chromatin modifications play a fundamental role in regulating many cellular processes. The coordinated activities of various chromatin-remodelling and -modifying complexes are crucial in maintaining distinct chromatin neighbourhoods, which in turn ensure appropriate gene expression, as well as DNA replication, repair, and recombination. SWR1-C is an ATP-dependent histone deposition complex for the histone variant H2A.Z, whereas NuA4 is a histone acetyltransferase for histones H4, H2A, and H2A.Z. Together the NuA4 and SWR1-C chromatin-modifying complexes alter the chromatin structure through 3 distinct modifications in yeast: post-translational addition of chemical groups, ATP-dependent chromatin remodelling, and histone variant incorporation. These 2 multi-protein complexes share 4 subunits and function together to regulate the circuitry of H2A.Z biology. The components and functions of both multi-protein complexes are evolutionarily conserved and play important roles in multi-cellular development and cellular differentiation in higher eukaryotes. This review will summarize recent findings about NuA4 and SWR1-C and will focus on the connection between these complexes by investigating their physical and functional interactions through eukaryotic evolution.

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