scholarly journals The Yeast RSC Chromatin-Remodeling Complex Is Required for Kinetochore Function in Chromosome Segregation

2003 ◽  
Vol 23 (9) ◽  
pp. 3202-3215 ◽  
Author(s):  
Jing-mei Hsu ◽  
Jian Huang ◽  
Pamela B. Meluh ◽  
Brehon C. Laurent
Keyword(s):  
Chromatin Remodeling ◽  
Centromeric Chromatin ◽  
Centromeric Dna ◽  
Chromosome Transmission ◽  
Sister Chromatids ◽  
Chromatin Remodeling Complex ◽  
Histone H3 Variant ◽  
Complex Protein ◽  
Genes Encoding ◽  
Kinetochore Function

ABSTRACT The accurate segregation of chromosomes requires the kinetochore, a complex protein machine that assembles onto centromeric DNA to mediate attachment of replicated sister chromatids to the mitotic spindle apparatus. This study reveals an important role for the yeast RSC ATP-dependent chromatin-remodeling complex at the kinetochore in chromosome transmission. Mutations in genes encoding two core subunits of RSC, the ATPase Sth1p and the Snf5p homolog Sfh1p, interact genetically with mutations in genes encoding kinetochore proteins and with a mutation in centromeric DNA. RSC also interacts genetically and physically with the histone and histone variant components of centromeric chromatin. Importantly, RSC is localized to centromeric and centromere-proximal chromosomal regions, and its association with these loci is dependent on Sth1p. Both sth1 and sfh1 mutants exhibit altered centromeric and centromere-proximal chromatin structure and increased missegregation of authentic chromosomes. Finally, RSC is not required for centromeric deposition of the histone H3 variant Cse4p, suggesting that RSC plays a role in reconfiguring centromeric and flanking nucleosomes following Cse4p recruitment for proper chromosome transmission.

scholarly journals The ctf13-30/CTF13 Genomic Haploinsufficiency Modifier Screen Identifies the Yeast Chromatin Remodeling Complex RSC, Which Is Required for the Establishment of Sister Chromatid Cohesion

2004 ◽  
Vol 24 (3) ◽  
pp. 1232-1244 ◽  
Author(s):  
Kristin K. Baetz ◽  
Nevan J. Krogan ◽  
Andrew Emili ◽  
Jack Greenblatt ◽  
Philip Hieter
Keyword(s):  
Chromatin Remodeling ◽  
Chromosome Segregation ◽  
High Fidelity ◽  
Chromosome Transmission ◽  
New Genes ◽  
Sister Chromatids ◽  
Chromatin Remodeling Complex ◽  
Chromatid Cohesion ◽  
Spindle Microtubules ◽  
Mitosis And Meiosis

ABSTRACT The budding yeast centromere-kinetochore complex ensures high-fidelity chromosome segregation in mitosis and meiosis by mediating the attachment and movement of chromosomes along spindle microtubules. To identify new genes and pathways whose function impinges on chromosome transmission, we developed a genomic haploinsufficiency modifier screen and used ctf13-30, encoding a mutant core kinetochore protein, as the reference point. We demonstrate through a series of secondary screens that the genomic modifier screen is a successful method for identifying genes that encode nonessential proteins required for the fidelity of chromosome segregation. One gene isolated in our screen was RSC2, a nonessential subunit of the RSC chromatin remodeling complex. rsc2 mutants have defects in both chromosome segregation and cohesion, but the localization of kinetochore proteins to centromeres is not affected. We determined that, in the absence of RSC2, cohesin could still associate with chromosomes but fails to achieve proper cohesion between sister chromatids, indicating that RSC has a role in the establishment of cohesion. In addition, numerous subunits of RSC were affinity purified and a new component of RSC, Rtt102, was identified. Our work indicates that only a subset of the nonessential RSC subunits function in maintaining chromosome transmission fidelity.

scholarly journals CENP-H–containing Complex Facilitates Centromere Deposition of CENP-A in Cooperation with FACT and CHD1

2009 ◽  
Vol 20 (18) ◽  
pp. 3986-3995 ◽  
Author(s):  
Masahiro Okada ◽  
Katsuya Okawa ◽  
Toshiaki Isobe ◽  
Tatsuo Fukagawa
Keyword(s):  
Chromatin Remodeling ◽  
Mutant Cell ◽  
Histone H3 ◽  
Dependent Manner ◽  
Centromeric Chromatin ◽  
Conditional Mutant ◽  
Histone H3 Variant ◽  
A Subunit

Centromere identity is thought to be determined by epigenetic mechanisms. The centromere-specific histone H3 variant CENP-A plays a central role in specifying the locus where the centromere is constructed. However, the precise mechanisms that target CENP-A to centromeric chromatin are poorly understood. Here, we show that facilitates chromatin transcription (FACT) localizes to centromeres in a CENP-H–containing complex-dependent manner. In conditional mutant cell lines for SSRP1, a subunit of FACT, centromere targeting of newly synthesized CENP-A is severely inhibited. The chromatin remodeling factor CHD1 binds to SSRP1 both in vivo and in vitro and associates with centromeres. The centromeric localization of CHD1 is lost in SSRP1-depleted cells. RNA interference knockdown of CHD1 leads to a decrease in the amount of centromere localized CENP-A. These findings indicate that the CENP-H–containing complex facilitates deposition of newly synthesized CENP-A into centromeric chromatin in cooperation with FACT and CHD1.

scholarly journals Determinants of Sir2-Mediated, Silent Chromatin Cohesion

2016 ◽  
Vol 36 (15) ◽  
pp. 2039-2050 ◽  
Author(s):  
Yu-Fan Chen ◽  
Chia-Ching Chou ◽  
Marc R. Gartenberg
Keyword(s):  
Chromatin Remodeling ◽  
Molecular Basis ◽  
Charged Surface ◽  
Silent Chromatin ◽  
Chromatin Domains ◽  
Content Type ◽  
Chromatin Remodelers ◽  
Sister Chromatids ◽  
Chromatin Remodeling Complex ◽  
Chromatid Cohesion

Cohesin associates with distinct sites on chromosomes to mediate sister chromatid cohesion. Single cohesin complexes are thought to bind by encircling both sister chromatids in a topological embrace. Transcriptionally repressed chromosomal domains in the yeastSaccharomyces cerevisiaerepresent specialized sites of cohesion where cohesin binds silent chromatin in a Sir2-dependent fashion. In this study, we investigated the molecular basis for Sir2-mediated cohesion. We identified a cluster of charged surface residues of Sir2, collectively termed the EKDK motif, that are required for cohesin function. In addition, we demonstrated that Esc8, a Sir2-interacting factor, is also required for silent chromatin cohesion. Esc8 was previously shown to associate with Isw1, the enzymatic core of ISW1 chromatin remodelers, to form a variant of the ISW1a chromatin remodeling complex. WhenESC8was deleted or the EKDK motif was mutated, cohesin binding at silenced chromatin domains persisted but cohesion of the domains was abolished. The data are not consistent with cohesin embracing both sister chromatids within silent chromatin domains. Transcriptional silencing remains largely intact in strains lackingESC8or bearing EKDK mutations, indicating that silencing and cohesion are separable functions of Sir2 and silent chromatin.

scholarly journals A unique missense allele of BAF155, a core BAF chromatin remodeling complex protein, causes neural tube closure defects in mice

2014 ◽  
Vol 74 (5) ◽  
pp. 483-497 ◽  
Author(s):  
Laura Harmacek ◽  
Dawn E. Watkins-Chow ◽  
Jianfu Chen ◽  
Kenneth L. Jones ◽  
William J. Pavan ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Neural Tube ◽  
Neural Tube Closure ◽  
Chromatin Remodeling Complex ◽  
Complex Protein ◽  
Missense Allele ◽  
Tube Closure ◽  
Neural Tube Closure Defects

scholarly journals HJURP interaction with the condensin II complex during G1 promotes CENP-A deposition

2017 ◽  
Vol 28 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Meghan C. Barnhart-Dailey ◽  
Prasad Trivedi ◽  
P. Todd Stukenberg ◽  
Daniel R. Foltz
Keyword(s):  
Chromatin Remodeling ◽  
Chromosome Segregation ◽  
Mitotic Exit ◽  
Human Cells ◽  
Centromeric Chromatin ◽  
Kinetochore Assembly ◽  
Chromatin Remodeling Complex ◽  
Chromatin Template ◽  
Assembly Factor ◽  
Laco Array

Centromeric chromatin is required for kinetochore assembly during mitosis and accurate chromosome segregation. A unique nucleosome containing the histone H3–specific variant CENP-A is the defining feature of centromeric chromatin. In humans, CENP-A nucleosome deposition occurs in early G1 just after mitotic exit at the time when the CENP-A deposition machinery localizes to centromeres. The mechanism by which CENP-A is deposited onto an existing, condensed chromatin template is not understood. Here we identify the selective association of the CENP-A chaperone HJURP with the condensin II complex and not condensin I. We show CAPH2 is present at centromeres during early G1 at the time when CENP-A deposition is occurring. CAPH2 localization to early G1 centromeres is dependent on HJURP. The CENP-A chaperone and assembly factor HJURP induces decondensation of a noncentromeric LacO array, and this decondensation is modulated by the condensin II complex. We show that condensin II function at the centromere is required for new CENP-A deposition in human cells. These data demonstrate that HJURP selectively recruits the condensin II chromatin-remodeling complex to facilitate CENP-A deposition in human cells.

scholarly journals De Novo Kinetochore Assembly Requires the Centromeric Histone H3 Variant

2005 ◽  
Vol 16 (12) ◽  
pp. 5649-5660 ◽  
Author(s):  
Kimberly A. Collins ◽  
Andrea R. Castillo ◽  
Sean Y. Tatsutani ◽  
Sue Biggins
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
De Novo ◽  
Histone H3 ◽  
Centromeric Chromatin ◽  
Centromeric Dna ◽  
Kinetochore Assembly ◽  
Histone H3 Variant ◽  
Chromosome Attachment ◽  
Dna Specificity

Kinetochores mediate chromosome attachment to the mitotic spindle to ensure accurate chromosome segregation. Budding yeast is an excellent organism for kinetochore assembly studies because it has a simple defined centromere sequence responsible for the localization of >65 proteins. In addition, yeast is the only organism where a conditional centromere is available to allow studies of de novo kinetochore assembly. Using a conditional centromere, we found that yeast kinetochore assembly is not temporally restricted and can occur in both G1 phase and prometaphase. We performed the first investigation of kinetochore assembly in the absence of the centromeric histone H3 variant Cse4 and found that all proteins tested depend on Cse4 to localize. Consistent with this observation, Cse4-depleted cells had severe chromosome segregation defects. We therefore propose that yeast kinetochore assembly requires both centromeric DNA specificity and centromeric chromatin.

scholarly journals Actin-Related Protein 4 Interacts with PIE1 and Regulates Gene Expression in Arabidopsis

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 520
Author(s):  
Wenfeng Nie ◽  
Jinyu Wang
Keyword(s):  
Gene Expression ◽  
Plant Growth ◽  
Chromatin Remodeling ◽  
Leaf Size ◽  
Early Flowering ◽  
Physical Interaction ◽  
Loss Of Function ◽  
Single Nucleotide Change ◽  
Chromatin Remodeling Complex ◽  
Related Proteins

As essential structural components of ATP-dependent chromatin-remodeling complex, the nucleolus-localized actin-related proteins (ARPs) play critical roles in many biological processes. Among them, ARP4 is identified as an integral subunit of chromatin remodeling complex SWR1, which is conserved in yeast, humans and plants. It was shown that RNAi mediated knock-down of Arabidopsis thaliana ARP4 (AtARP4) could affect plant development, specifically, leading to early flowering. However, so far, little is known about how ARP4 functions in the SWR1 complex in plant. Here, we identified a loss-of-function mutant of AtARP4 with a single nucleotide change from glycine to arginine, which had significantly smaller leaf size. The results from the split luciferase complementation imaging (LCI) and yeast two hybrid (Y2H) assays confirmed its physical interaction with the scaffold and catalytic subunit of SWR1 complex, photoperiod-independent early flowering 1 (PIE1). Furthermore, mutation of AtARP4 caused altered transcription response of hundreds of genes, in which the number of up-regulated differentially expressed genes (DEGs) was much larger than those down-regulated. Although most DEGs in atarp4 are related to plant defense and response to hormones such as salicylic acid, overall, it has less overlapping with other swr1 mutants and the hta9 hta11 double-mutant. In conclusion, our results reveal that AtARP4 is important for plant growth and such an effect is likely attributed to its repression on gene expression, typically at defense-related loci, thus providing some evidence for the coordination of plant growth and defense, while the regulatory patterns and mechanisms are distinctive from other SWR1 complex components.

scholarly journals Interplay of BAF and MLL4 promotes cell type-specific enhancer activation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Young-Kwon Park ◽  
Ji-Eun Lee ◽  
Zhijiang Yan ◽  
Kaitlin McKernan ◽  
Tommy O’Haren ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Chromatin Remodeling ◽  
Direct Evidence ◽  
Cell Type ◽  
Chromatin Regulators ◽  
Chromatin Remodeling Complex ◽  
Histone H3k4 ◽  
Cell Type Specific ◽  
Pioneer Transcription Factor ◽  
Factor C

AbstractCell type-specific enhancers are activated by coordinated actions of lineage-determining transcription factors (LDTFs) and chromatin regulators. The SWI/SNF chromatin remodeling complex BAF and the histone H3K4 methyltransferase MLL4 (KMT2D) are both implicated in enhancer activation. However, the interplay between BAF and MLL4 in enhancer activation remains unclear. Using adipogenesis as a model system, we identify BAF as the major SWI/SNF complex that colocalizes with MLL4 and LDTFs on active enhancers and is required for cell differentiation. In contrast, the promoter enriched SWI/SNF complex PBAF is dispensable for adipogenesis. By depleting BAF subunits SMARCA4 (BRG1) and SMARCB1 (SNF5) as well as MLL4 in cells, we show that BAF and MLL4 reciprocally regulate each other’s binding on active enhancers before and during adipogenesis. By focusing on enhancer activation by the adipogenic pioneer transcription factor C/EBPβ without inducing cell differentiation, we provide direct evidence for an interdependent relationship between BAF and MLL4 in activating cell type-specific enhancers. Together, these findings reveal a positive feedback between BAF and MLL4 in promoting LDTF-dependent activation of cell type-specific enhancers.

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