Heterochromatin proteins and the control of heterochromatic gene silencing in Arabidopsis

Fischer, Andreas; Hofmann, Ingo; Naumann, Kathrin; Reuter, Günter

doi:10.1016/j.jplph.2005.10.015

Cited by 69 publications

(60 citation statements)

References 63 publications

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“…Nevertheless, DNA methylation of pericentromeric repeats was normal, indicating that CAF-1 is not required for maintenance of DNA methylation (Schönrock et al, 2006). Immunolocalization experiments have shown that dimethylation of the K9 residue of histone H3 (H3K9me2), a typical mark of heterochromatin in Arabidopsis (Fischer et al, 2006;Fransz et al, 2006;Fuchs et al, 2006), remains enriched in heterochromatic chromocenters of fas1 nuclei (Kirik et al, 2006;Schö nrock et al, 2006). These data have been used in support of the notion that chromatin in fas1 mutants presents an open conformation.…”

Section: Loss Of Fas1 Provokes Removal Of Epigenetic Silencing Marks mentioning

confidence: 81%

E2F RegulatesFASCIATA1, a Chromatin Assembly Gene Whose Loss Switches on the Endocycle and Activates Gene Expression by Changing the Epigenetic Status

2007

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Maintenance of genome integrity depends on histone chaperone-mediated chromatin reorganization. DNA replicationassociated nucleosome deposition relies on chromatin assembly factor-1 (CAF-1). Depletion of CAF-1 in human cells leads to cell death, whereas in Arabidopsis (Arabidopsis thaliana), where it is involved in heterochromatin compaction and homologous recombination, plants are viable. The mechanism that makes the lack of CAF-1 activity compatible with development is not known. Here, we show that the FASCIATA1 (FAS1) gene, which encodes the CAF-1 large subunit, is a target of E2F transcription factors. Mutational studies demonstrate that one of the two E2F binding sites in its promoter has an activator role, whereas the other has a repressor function. Loss of FAS1 results in reduced type A cyclin-dependent kinase activity, inhibits mitotic progression, and promotes a precocious and systemic switch to the endocycle program. Selective up-regulation of the expression of a subset of genes, including those involved in activation of the G2 DNA damage checkpoint, also occurs upon FAS1 loss. This activation is not the result of a global change in chromatin structure, but depends on selective epigenetic changes in histone acetylation and methylation within a small region in their promoters. This suggests that correct chromatin assembly during the S-phase is required to prevent unscheduled changes in the epigenetic marks of target genes. Interestingly, activation of the endocycle switch as well as introduction of activating histone marks in the same set of G2 checkpoint genes are detected upon treatment of wild-type plants with DNA-damaging treatments. Our results are consistent with a model in which defects in chromatin assembly during the S-phase and DNA damage signaling share part of a pathway, which ultimately leads to mitotic arrest and triggers the endocycle program. Together, this might be a bypass mechanism that makes development compatible with cell division arrest induced by DNA damage stress.

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Section: Loss Of Fas1 Provokes Removal Of Epigenetic Silencing Marks mentioning

confidence: 81%

E2F RegulatesFASCIATA1, a Chromatin Assembly Gene Whose Loss Switches on the Endocycle and Activates Gene Expression by Changing the Epigenetic Status

2007

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“…Indeed, H3S10ph facilitates RNA polymerase II release from promoter-proximal pausing in Drosophila (12) and binding of heterochromatin protein 1 (HP1), a polypeptide involved in heterochromatin formation, to H3K9me3 is disrupted by the presence of a phosphate group on Ser-10 (14, 15). However, H3S10ph has also been implicated in the marking of silent chromatin in postmitotic mammalian cells (14), and it is associated with heterochromatin in interphase cells of Arabidopsis (16). The puzzle posed by the correlation of H3S10ph with two apparently opposed chromatin states (active euchromatin and silent heterochromatin) is not clearly understood and emphasizes that the meaning of posttranslational histone modifications may depend on genomic context.…”

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confidence: 99%

The MUT9p kinase phosphorylates histone H3 threonine 3 and is necessary for heritable epigenetic silencing in Chlamydomonas

Casas-Mollano¹,

Jeong²,

Xu³

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

101

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“…Methylation of histone H3 at lysine 4 (H3K4me) is crucial for gene activation and repression (2)(3)(4)(5)(6). Recognition of H3K4me3 by proteins containing a plant homeodomain (PHD) is an initial event that ultimately leads to changes in the acetylation and/or methylation status in the vicinity of H3K4me3 (2)(3)(4)6).…”

mentioning

confidence: 99%

“…Thus, the identification of H3K4me3 effector proteins has become a subject of primary importance. Some histone marks, e.g., the association of H3K4me3 with active genes, are common to animal and plant cells, but others are plant specific (5,7). For example, H3K9me3 and H4K20me3, which in animal cells are detected in heterochromatin, localize to euchromatin in plants (5,7,8).…”

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confidence: 99%

Arabidopsis ORC1 is a PHD-containing H3K4me3 effector that regulates transcription

Sánchez

Gutiérrez

2009

Proc. Natl. Acad. Sci. U.S.A.

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Control of gene expression depends on a complex and delicate balance of various posttranslational modifications of histones. However, the relevance of specific combinations of histone modifications is not fully defined. Downstream effector proteins recognize particular histone modifications and transduce this information into gene expression patterns. Methylation of histone H3 at lysine 4 (H3K4me) is a landmark of gene expression control in eukaryotes. Its recognition depends on the presence in the effector protein of a motif termed plant homeodomain (PHD) that specifically binds to H3K4me3. Here, we establish that Arabidopsis ORC1, the large subunit of the origin recognition complex involved in defining origins of DNA replication, functions as a transcriptional activator of a subset of genes, the promoters of which are preferentially bound by ORC1. Arabidopsis ORC1 contains a PHD and binds to H3K4me3. In addition to H4 acetylation, ORC1 binding correlates with increased H4K20me3 in the proximal promoter region of ORC1 targets. This suggests that H4K20me3, unlike in animal cells, is associated with transcriptional activation in Arabidopsis. Thus, our data provide a molecular basis for the opposite role of ORC1 in transcriptional activation in plants and repression in animals. Since only ORC1 proteins of plant species contain a PHD, we propose that plant ORC1 constitutes a novel class of H3K4me3 effector proteins characteristic of the plant kingdom.cell cycle transcription ͉ histone H3 lysine 4 methylation ͉ ORC1 DNA replication ͉ plant homeodomain

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Heterochromatin proteins and the control of heterochromatic gene silencing in Arabidopsis

Cited by 69 publications

References 63 publications

E2F RegulatesFASCIATA1, a Chromatin Assembly Gene Whose Loss Switches on the Endocycle and Activates Gene Expression by Changing the Epigenetic Status

E2F RegulatesFASCIATA1, a Chromatin Assembly Gene Whose Loss Switches on the Endocycle and Activates Gene Expression by Changing the Epigenetic Status

The MUT9p kinase phosphorylates histone H3 threonine 3 and is necessary for heritable epigenetic silencing in Chlamydomonas

Arabidopsis ORC1 is a PHD-containing H3K4me3 effector that regulates transcription

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