Phosphorylation of Histone H3 at Serine 10 Cannot Account Directly for the Detachment of Human Heterochromatin Protein 1γ from Mitotic Chromosomes in Plant Cells

Telomeres share the ability to silence nearby transcription with heterochromatin, but the requirement of heterochromatin proteins for most telomere functions is unknown. The fission yeast Rik1 protein is required for heterochromatin formation at centromeres and the mating-type locus, as it recruits the Clr4 histone methyltransferase, whose modification of histone H3 triggers binding by Swi6, a conserved protein involved in spreading of heterochromatin. Here, we demonstrate that Rik1 and Clr4, but not Swi6, are required along with the telomere protein Taz1 for crucial chromosome movements during meiosis. However, Rik1 is dispensable for the protective roles of telomeres in preventing chromosome end-fusion. Thus, a Swi6-independent heterochromatin function distinct from that at centromeres and the mating-type locus operates at telomeres during sexual differentiation.

Download Full-text

Cell Cycle-dependent Expression and Nucleolar Localization of hCAP-H

Molecular Biology of the Cell ◽

10.1091/mbc.12.11.3527 ◽

2001 ◽

Vol 12 (11) ◽

pp. 3527-3537 ◽

Cited By ~ 32

Author(s):

Olga A. Cabello ◽

Elena Eliseeva ◽

WeiGong He ◽

Hagop Youssoufian ◽

Sharon E. Plon ◽

...

Keyword(s):

Cell Cycle ◽

Histone H3 ◽

Chromosome Condensation ◽

Nucleolar Localization ◽

Mitotic Chromosomes ◽

Proliferating Cells ◽

Protein Levels ◽

Sister Chromatids ◽

H3 Phosphorylation ◽

Histone H3 Phosphorylation

Condensin is a conserved 13S heteropentamer composed of two nonidentical structural maintenance of chromosome (SMC) family proteins, in Xenopus XCAP-C and XCAP-E, and three regulatory subunits, XCAP-D2, XCAP-G, and XCAP-H. Both biochemical and genetic analyses have demonstrated an essential role for the 13S condensin complex in mitotic chromosome condensation. Further, a potential requirement for condensin in completion of chromatid arm separation in early anaphase is demonstrated by the mutational phenotypes of the Drosophila homologues ofXCAP-H, barren and XCAP-C,DmSMC4. In this study we have investigated the expression and subcellular distribution of hCAP-H, the human homolog of XCAP-H, in order to better understand its cellular functions. Transcription of hCAP-H was restricted to proliferating cells with highest expression during the G2 phase of the cell cycle. In contrast, cellular hCAP-H protein levels were constant throughout the cell cycle. hCAP-H was found to be associated with mitotic chromosomes exhibiting a nonuniform but symmetric distribution along sister chromatids. The symmetry of hCAP-H association with sister chromatids suggests that there are sequence-dependent domains of condensin aggregation. During interphase hCAP-H, -C, and -E, have distinct punctate nucleolar localization, suggesting that condensin may associate with and modulate the conformation and function of rDNA. hCAP-H association with condensed chromatin was not observed in the early phase of chromosome condensation when histone H3 phosphorylation has already taken place. This finding is consistent with the hypothesis that histone H3 phosphorylation precedes condensin-mediated condensation.

Download Full-text

Dynamic variation of histone H3 trimethyl Lys4 (H3K4me3) and heterochromatin protein 1 (HP1) with employment length in nickel smelting workers

Biomarkers ◽

10.1080/1354750x.2016.1203996 ◽

2016 ◽

Vol 22 (5) ◽

pp. 420-428 ◽

Cited By ~ 1

Author(s):

Yanhong Zhao ◽

Ning Cheng ◽

Min Dai ◽

Hongquan Pu ◽

Tongzhang Zheng ◽

...

Keyword(s):

Histone H3 ◽

Heterochromatin Protein 1 ◽

Heterochromatin Protein ◽

Dynamic Variation ◽

Nickel Smelting

Download Full-text

Pericentromeric Heterochromatin Domains Are Maintained without Accumulation of HP1

Molecular Biology of the Cell ◽

10.1091/mbc.e06-01-0025 ◽

2007 ◽

Vol 18 (4) ◽

pp. 1464-1471 ◽

Cited By ~ 23

Author(s):

Julio Mateos-Langerak ◽

Maartje C. Brink ◽

Martijn S. Luijsterburg ◽

Ineke van der Kraan ◽

Roel van Driel ◽

...

Keyword(s):

Histone H3 ◽

Dominant Negative ◽

Pericentromeric Heterochromatin ◽

Heterochromatin Protein 1 ◽

Dapi Staining ◽

Heterochromatin Protein ◽

3T3 Fibroblasts ◽

Heterochromatin Structure ◽

Hp1 Proteins

The heterochromatin protein 1 (HP1) family is thought to be an important structural component of heterochromatin. HP1 proteins bind via their chromodomain to nucleosomes methylated at lysine 9 of histone H3 (H3K9me). To investigate the role of HP1 in maintaining heterochromatin structure, we used a dominant negative approach by expressing truncated HP1α or HP1β proteins lacking a functional chromodomain. Expression of these truncated HP1 proteins individually or in combination resulted in a strong reduction of the accumulation of HP1α, HP1β, and HP1γ in pericentromeric heterochromatin domains in mouse 3T3 fibroblasts. The expression levels of HP1 did not change. The apparent displacement of HP1α, HP1β, and HP1γ from pericentromeric heterochromatin did not result in visible changes in the structure of pericentromeric heterochromatin domains, as visualized by DAPI staining and immunofluorescent labeling of H3K9me. Our results show that the accumulation of HP1α, HP1β, and HP1γ at pericentromeric heterochromatin domains is not required to maintain DAPI-stained pericentromeric heterochromatin domains and the methylated state of histone H3 at lysine 9 in such heterochromatin domains.

Download Full-text

Phosphorylation of histone H3 by Haspin regulates chromosome alignment and segregation during mitosis in maize

Journal of Experimental Botany ◽

10.1093/jxb/eraa506 ◽

2020 ◽

Author(s):

Yang Liu ◽

Chunhui Wang ◽

Handong Su ◽

James A Birchler ◽

Fangpu Han

Keyword(s):

Chromosome Segregation ◽

Histone H3 ◽

Heterochromatin Protein 1 ◽

Heterochromatin Protein ◽

Factor B ◽

Microtubule Attachment ◽

Chromosome Alignment ◽

Chromosomal Passenger ◽

Mitosis And Meiosis

Abstract In human cells, Haspin-mediated histone H3 threonine 3 (H3T3) phosphorylation promotes centromeric localization of the chromosomal passenger complex, thereby ensuring proper kinetochore–microtubule attachment. Haspin also binds to PDS5 cohesin-associated factor B (Pds5B), antagonizing the Wings apart-like protein homolog (Wapl)–Pds5B interaction and thus preventing Wapl from releasing centromeric cohesion during mitosis. However, the role of Haspin in plant chromosome segregation is not well understood. Here, we show that in maize (Zea mays) mitotic cells, ZmHaspin localized to the centromere during metaphase and anaphase, whereas it localized to the telomeres during meiosis. These results suggest that ZmHaspin plays different roles during mitosis and meiosis. Knockout of ZmHaspin led to decreased H3T3 phosphorylation and histone H3 serine 10 phosphorylation, and defects in chromosome alignment and segregation in mitosis. These lines of evidence suggest that Haspin regulates chromosome segregation in plants via the mechanism described for humans, namely, H3T3 phosphorylation. Plant Haspin proteins lack the RTYGA and PxVxL motifs needed to bind Pds5B and heterochromatin protein 1, and no obvious cohesion defects were detected in ZmHaspin knockout plants. Taken together, these results highlight the conserved but slightly different roles of Haspin proteins in cell division in plants and in animals.

Download Full-text

HP1 Binding to Chromatin Methylated at H3K9 Is Enhanced by Auxiliary Factors

Molecular and Cellular Biology ◽

10.1128/mcb.01576-06 ◽

2006 ◽

Vol 27 (2) ◽

pp. 453-465 ◽

Cited By ~ 83

Author(s):

Ragnhild Eskeland ◽

Anton Eberharter ◽

Axel Imhof

Keyword(s):

Histone H3 ◽

Chromatin Modifications ◽

Multiple Target ◽

Heterochromatin Protein 1 ◽

Heterochromatin Protein ◽

Heterochromatin Formation ◽

Condensed Form ◽

Target Sites ◽

Reconstituted System

ABSTRACT A large portion of the eukaryotic genome is packaged into transcriptionally silent heterochromatin. Several factors that play important roles during the establishment and maintenance of this condensed form have been identified. Methylation of lysine 9 within histone H3 and the subsequent binding of the chromodomain protein heterochromatin protein 1 (HP1) are thought to initiate heterochromatin formation in vivo and to propagate a heterochromatic state lasting through several cell divisions. For the present study we analyzed the binding of HP1 to methylated chromatin in a fully reconstituted system. In contrast to its strong binding to methylated peptides, HP1 binds only weakly to methylated chromatin. However, the addition of recombinant SU(VAR) protein, such as ACF1 or SU(VAR)3-9, facilitates HP1 binding to chromatin methylated at lysine 9 within the H3 N terminus (H3K9). We propose that HP1 has multiple target sites that contribute to its recognition of chromatin, only one of them being methylated at H3K9. These findings have implications for the mechanisms of recognition of specific chromatin modifications in vivo.

Download Full-text

A Bromodomain Protein, MCAP, Associates with Mitotic Chromosomes and Affects G2-to-M Transition

Molecular and Cellular Biology ◽

10.1128/mcb.20.17.6537-6549.2000 ◽

2000 ◽

Vol 20 (17) ◽

pp. 6537-6549 ◽

Cited By ~ 188

Author(s):

Anup Dey ◽

Jan Ellenberg ◽

Andrea Farina ◽

Allen E. Coleman ◽

Tetsuo Maruyama ◽

...

Keyword(s):

Mitotic Chromosome ◽

Histone H3 ◽

Growth Stimulation ◽

Nuclear Factor ◽

Cell Nuclei ◽

Mitotic Chromosomes ◽

H3 Phosphorylation ◽

Chromosomal Condensation ◽

Histone H3 Phosphorylation ◽

Exquisite Specificity

ABSTRACT We describe a novel nuclear factor called mitotic chromosome-associated protein (MCAP), which belongs to the poorly understood BET subgroup of the bromodomain superfamily. Expression of the 200-kDa MCAP was linked to cell division, as it was induced by growth stimulation and repressed by growth inhibition. The most notable feature of MCAP was its association with chromosomes during mitosis, observed at a time when the majority of nuclear regulatory factors were released into the cytoplasm, coinciding with global cessation of transcription. Indicative of its predominant interaction with euchromatin, MCAP localized on mitotic chromosomes with exquisite specificity: (i) MCAP-chromosome association became evident subsequent to the initiation of histone H3 phosphorylation and early chromosomal condensation; and (ii) MCAP was absent from centromeres, the sites of heterochromatin. Supporting a role for MCAP in G2/M transition, microinjection of anti-MCAP antibody into HeLa cell nuclei completely inhibited the entry into mitosis, without abrogating the ongoing DNA replication. These results suggest that MCAP plays a role in a process governing chromosomal dynamics during mitosis.

Download Full-text