scholarly journals Overlapping Roles in Chromosome Segregation for Heterochromatin Protein 1 (Swi6) and DDK in Schizosaccharomyces pombe

Genetics ◽  
2019 ◽  
Vol 212 (2) ◽  
pp. 417-430 ◽  
Author(s):  
Kuo-Fang Shen ◽  
Susan L. Forsburg
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Chromosome Segregation ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein

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

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.

scholarly journals Epigenetic displacement of HP1 from heterochromatin by HIV-1 Vpr causes premature sister chromatid separation

2011 ◽  
Vol 194 (5) ◽  
pp. 721-735 ◽  
Author(s):  
Mari Shimura ◽  
Yusuke Toyoda ◽  
Kenta Iijima ◽  
Masanobu Kinomoto ◽  
Kenzo Tokunaga ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Chromosomes ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Viral Pathogen ◽  
Chromatid Cohesion ◽  
Epigenetic Disruption ◽  
First Time ◽  
Order Structures ◽  
Hiv 1

Although pericentromeric heterochromatin is essential for chromosome segregation, its role in humans remains controversial. Dissecting the function of HIV-1–encoded Vpr, we unraveled important properties of heterochromatin during chromosome segregation. In Vpr-expressing cells, hRad21, hSgo1, and hMis12, which are crucial for proper chromosome segregation, were displaced from the centromeres of mitotic chromosomes, resulting in premature chromatid separation (PCS). Interestingly, Vpr displaced heterochromatin protein 1-α (HP1-α) and HP1-γ from chromatin. RNA interference (RNAi) experiments revealed that down-regulation of HP1-α and/or HP1-γ induced PCS, concomitant with the displacement of hRad21. Notably, Vpr stimulated the acetylation of histone H3, whereas p300 RNAi attenuated the Vpr-induced displacement of HP1-α and PCS. Furthermore, Vpr bound to p300 that was present in insoluble regions of the nucleus, suggesting that Vpr aberrantly recruits the histone acetyltransferase activity of p300 to chromatin, displaces HP1-α, and causes chromatid cohesion defects. Our study reveals for the first time centromere cohesion impairment resulting from epigenetic disruption of higher-order structures of heterochromatin by a viral pathogen.

scholarly journals Reinventing Heterochromatin in Budding Yeasts: Sir2 and the Origin Recognition Complex Take Center Stage

2011 ◽  
Vol 10 (9) ◽  
pp. 1183-1192 ◽  
Author(s):  
Meleah A. Hickman ◽  
Cara A. Froyd ◽  
Laura N. Rusche
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Schizosaccharomyces Pombe ◽  
Mating Type ◽  
Origin Recognition Complex ◽  
Transcriptional Silencing ◽  
Gene Duplications ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Content Type ◽  
Sir Proteins

ABSTRACTThe transcriptional silencing of the cryptic mating-type loci inSaccharomyces cerevisiaeis one of the best-studied models of repressive heterochromatin. However, this type of heterochromatin, which is mediated by the Sir proteins, has a distinct molecular composition compared to the more ubiquitous type of heterochromatin found inSchizosaccharomyces pombe, other fungi, animals, and plants and characterized by the presence of HP1 (heterochromatin protein 1). This review discusses how the loss of important heterochromatin proteins, including HP1, in the budding yeast lineage presented an evolutionary opportunity for the development and diversification of alternative varieties of heterochromatin, in which the conserved deacetylase Sir2 and the replication protein Orc1 play key roles. In addition, we highlight how this diversification has been facilitated by gene duplications and has contributed to adaptations in lifestyle.

Heterochromatin protein 1 is required for correct chromosome segregation in Drosophila embryos

1995 ◽  
Vol 108 (4) ◽  
pp. 1419-1431 ◽  
Author(s):  
R. Kellum ◽  
B.M. Alberts
Keyword(s):  
Chromosome Segregation ◽  
Position Effect ◽  
Chromosome Morphology ◽  
Chromosome Condensation ◽  
Centromeric Heterochromatin ◽  
Position Effect Variegation ◽  
Loss Of Function ◽  
Heterochromatin Protein 1 ◽  
Gene Encoding ◽  
Heterochromatin Protein

Heterochromatin protein 1 is associated with centromeric heterochromatin in Drosophila, mice, and humans. Loss of function mutations in the gene encoding heterochromatin protein 1 in Drosophila, Suppressor of variegation2-5, decrease the mosaic repression observed for euchromatic genes that have been juxtaposed to centromeric heterochromatin. These heterochromatin protein 1 mutations not only suppress this position-effect variegation, but also cause recessive embryonic lethality. In this study, we analyze the latter phenotype in the hope of gaining insight into heterochromatin function. In our analyses of four alleles of Suppressor of variegation2-5, the lethality was found to be associated with defects in chromosome morphology and segregation. While some of these defects are seen throughout embryonic development, both the frequency and severity of the defects are greatest between cycles 10 and 14 when zygotic transcription of the Suppressor of variegation2-5 gene apparently begins. By this time in development, heterochromatin protein 1 levels are diminished by four-fold in a quarter of the embryos produced by parents that are both heterozygous for a null allele (Suppressor of variegation2-5(05)). In a live analysis of the phenotype, we find prophase to be lengthened by more than two-fold in Suppressor of variegation2-5(05) mutant embryos with subsequent defects in chromosome segregation. The elongated prophase suggests that the segregation phenotype is a consequence of defects in events that occur during prophase, either in chromosome condensation or kinetochore assembly or function. Immunostaining with an antibody against a centromerespecific antigen indicates that the kinetochores of most chromosomes are functional. The immunostaining results are more consistent with defects in chromosome condensation being responsible for the segregation phenotype.

scholarly journals BRD4 facilitates DNA damage response and represses CBX5/Heterochromatin protein 1 (HP1)

Oncotarget ◽  
2017 ◽  
Vol 8 (31) ◽  
pp. 51402-51415 ◽  
Author(s):  
Georgios Pongas ◽  
Marianne K. Kim ◽  
Dong J. Min ◽  
Carrie D. House ◽  
Elizabeth Jordan ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Damage Response

scholarly journals SET‐domain bacterial effectors target heterochromatin protein 1 to activate host rDNA transcription

EMBO Reports ◽  
2013 ◽  
Vol 14 (8) ◽  
pp. 733-740 ◽  
Author(s):  
Ting Li ◽  
Qiuhe Lu ◽  
Guolun Wang ◽  
Hao Xu ◽  
Huanwei Huang ◽  
...  
Keyword(s):  
Set Domain ◽  
Rdna Transcription ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Bacterial Effectors
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