Drosophila Polycomb-group regulated chromatin inhibits the accessibility of a trans-activator to its target DNA.

Zink, Daniele; Paro, Renato

doi:10.1002/j.1460-2075.1995.tb00253.x

Cited by 182 publications

(181 citation statements)

References 53 publications

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“…This is consistent with the principles of gene silencing observed in Drosophila, where high doses of trans-activators can antagonize PcG-mediated silencing (61).…”

Section: Functional Interaction Of H-l(3)mbt and Tel-we Have Demonstrsupporting

confidence: 88%

The Human L(3)MBT Polycomb Group Protein Is a Transcriptional Repressor and Interacts Physically and Functionally with TEL (ETV6)

Boccuni

MacGrogan

Scandura³

et al. 2003

Journal of Biological Chemistry

106

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H-L(3)MBT, the human homolog of the ETS transcription factors, including TEL (translocation Ets leukemia). We report that H-L(3)MBT is a transcriptional repressor and that its activity is largely dependent on the presence of a region containing the three MBT repeats. H-L(3)MBT acts as a histone deacety-lase-independent transcriptional repressor, based on its lack of sensitivity to trichostatin A. We found that H-L(3)MBT binds in vivo to TEL, and we have mapped the region of interaction to their respective SPM/SAM domains. We show that the ability of TEL to repress TEL-responsive promoters is enhanced by the presence of H-L(3)MBT, an effect dependent on the H-L(3)MBT and the TEL interacting domains. These experiments suggest that histone deacetylase-independent transcriptional repression by TEL depends on the recruitment of PcG proteins. We speculate that the interaction of TEL with H-L(3)MBT can direct a PcG complex to genes repressed by TEL, stabilizing their repressed state.

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“…This is consistent with the principles of gene silencing observed in Drosophila, where high doses of trans-activators can antagonize PcG-mediated silencing (61).…”

Section: Functional Interaction Of H-l(3)mbt and Tel-we Have Demonstrsupporting

confidence: 88%

The Human L(3)MBT Polycomb Group Protein Is a Transcriptional Repressor and Interacts Physically and Functionally with TEL (ETV6)

Boccuni

MacGrogan

Scandura³

et al. 2003

Journal of Biological Chemistry

106

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“…By contrast, using a semiquantitative staining assay of whole Drosophila embryos, heterochromatin organized by Polycomb protein did not hamper expression of a -galactosidase transgene driven by T7 RNA polymerase (McCall and Bender, 1996). As a positive control, in the same system, a strong repression effect was found on activation by GAL4 factor (see also Zink and Paro, 1995). However, even within Drosophila, there are qualitative differences between telomeric and pericentric heterochromatin (Wallrath and Elgin, 1995).…”

Section: Discussionmentioning

confidence: 94%

“…Some of the repressor/corepressor proteins of yeast, Drosophila and mammals act by interfering with the process of transcriptional initiation (Hanna-Rose and Hansen, 1996), whereas the so-called Polycomb-group proteins, which are required for maintenance of the repressed state of the homeotic genes in Drosophila development and also are present in mammalian cells, most likely function by inducing the packaging of theirtarget genes into transcriptionally inactive heterochromatin (e.g., Zink and Paro, 1995;Strutt ef a/., 1997). The term transcriptional silencing is often used to describe repression effects in eukaryotes, notably repression over long distances as first described for the yeast mating type locus by K. Nasmyth and colleagues (Brand etal., 1985).…”

Section: Introductionmentioning

confidence: 99%

Silencing of RNA Polymerases II and III-Dependent Transcription by the KRAB Protein Domain of KOX1, a Krüppel-Type Zinc Finger Factor

Moosmann

Georgiev²,

Thiesen³

et al. 1997

Biological Chemistry

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The so-called KRAB domain, which is present in about one third of the vertebrate Krüppel-type zinc finger factors, has previously been shown to inhibit transcription in cis when tethered to promoter regions. Here we analyze this effect with fusions of the KRAB domain derived from KOX1/ZNF10 zinc finger protein to the heterologous DNA binding domains of both LexA and GAL4 factors. In transfected human cells, repression of reporter gene transcription is observed not only from proximal promoter positions, but also when KRAB is tethered to DNA at a remote position more than 1.8 kb downstream of the initiation site of transcription. Furthermore, KRAB-mediated silencing over short and long distances is not restricted to RNA polymerase II, since transcription by RNA polymerase III is also repressed. However, transcription by RNA polymerase I and by phage T7 RNA polymerase in mammalian cells are not significantly influenced by the KRAB domain. These latter results may indicate that repression by the KRAB domain, at least under our assay conditions, involves specific inhibition of some component(s) of RNA polymerase II and III transcription, rather than inducing some gross physical alteration of template chromatin structure.

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“…Immunostaining of ovaries was performed as described previously (57). Immunostaining of polytene squashes was performed as described previously (58).…”

Section: Discussionmentioning

confidence: 99%

The Drosophila DAXX-Like Protein (DLP) Cooperates with ASF1 for H3.3 Deposition and Heterochromatin Formation

Fromental-Ramain

Ramain

Hamiche

2017

Molecular and Cellular Biology

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Histone variants are nonallelic isoforms of canonical histones, and they are deposited, in contrast to canonical histones, in a replication-independent (RI) manner. RI deposition of H3.3, a histone variant from the H3.3 family, is mediated in mammals by distinct pathways involving either the histone regulator A (HIRA) complex or the death-associated protein (DAXX)/␣-thalassemia X-linked mental retardation protein (ATRX) complex. Here, we investigated the function of the Drosophila DAXX-like protein (DLP) by using both fly genetic approaches and protein biochemistry. DLP specifically interacts with H3.3 and shows a prominent localization on the base of the X chromosome, where it appears to act in concert with XNP, the Drosophila homolog of ATRX, in heterochromatin assembly and maintenance. The functional association between DLP and XNP is further supported by a series of experiments that illustrate genetic interactions and the DLP-XNP-dependent localization of specific chromosomal proteins. In addition, DLP both participates in the RI deposition of H3.3 and associates with anti-silencing factor 1 (ASF1). We suggest, in agreement with a recently proposed model, that DLP and ASF1 are part of a predeposition complex, which is recruited by XNP and is necessary to prevent DNA exposure in the nucleus.KEYWORDS DLP, heterochromatin, histone variant, H3.3, XNP, ASF1 I n the nucleus, DNA is packaged under the form of chromatin. The basic repeating unit of chromatin is the nucleosome, and the nucleosome core particle consists of approximately 146 bp of DNA wrapped around a histone octamer composed of two copies of each of the histones H2A, H2B, H3, and H4. (1, 2). Gene-rich domains are packaged into euchromatin, which is decondensed in interphase nuclei and is enriched for histone modifications characteristic of transcriptionally active regions. Moreover, euchromatin often exhibits high DNA accessibility. In contrast, gene-poor domains and repetitive sequences are packaged into condensed heterochromatin that carries histone modifications associated with transcriptional repression.In addition to the canonical core histones, cells express nonallelic-isoform histone variants (3). Histone variants have emerged as essential contributors to the regulation of chromatin structure, and they are involved in multiple processes, including chromatin stability, DNA repair, and transcriptional regulation. Canonical histones are almost exclusively expressed during the S phase of the cell cycle and are incorporated into chromatin in a DNA replication-dependent fashion, whereas replication-independent (RI) histone variants are expressed throughout the cell cycle.One of the best-studied histone variants is H3.3, which can replace the major species H3 (4). H3.3 is expressed and incorporated at all phases of the cell cycle (5). The available data suggest that H3.3 is a marker of active chromatin and associated with the

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Drosophila Polycomb-group regulated chromatin inhibits the accessibility of a trans-activator to its target DNA.

Cited by 182 publications

References 53 publications

The Human L(3)MBT Polycomb Group Protein Is a Transcriptional Repressor and Interacts Physically and Functionally with TEL (ETV6)

The Human L(3)MBT Polycomb Group Protein Is a Transcriptional Repressor and Interacts Physically and Functionally with TEL (ETV6)

Silencing of RNA Polymerases II and III-Dependent Transcription by the KRAB Protein Domain of KOX1, a Krüppel-Type Zinc Finger Factor

The Drosophila DAXX-Like Protein (DLP) Cooperates with ASF1 for H3.3 Deposition and Heterochromatin Formation

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