Corpus ID: 25743100

Hox repression of a target gene: extradenticle-independent, additive action through multiple monomer binding sites.

@article{Galant2002HoxRO,
  title={Hox repression of a target gene: extradenticle-independent, additive action through multiple monomer binding sites.},
  author={Ron Galant and C. Walsh and S. Carroll},
  journal={Development},
  year={2002},
  volume={129 13},
  pages={
          3115-26
        }
}
Homeotic (Hox) genes regulate the identity of structures along the anterior-posterior axis of most animals. The low DNA-binding specificities of Hox proteins have raised the question of how these transcription factors selectively regulate target gene expression. The discovery that the Extradenticle (Exd)/Pbx and Homothorax (Hth)/Meis proteins act as cofactors for several Hox proteins has advanced the view that interactions with cofactors are critical to the target selectivity of Hox proteins… Expand
Collaboration between Smads and a Hox protein in target gene repression
TLDR
This work finds that two Smad proteins, effectors of the Drosophila Dpp/TGF-β pathway, that are genetically required for the activation of the spalt (sal) gene in the wing, collaborate with the Hox protein Ultrabithorax (Ubx) to directly repress sal in the haltere. Expand
HOX proteins and their co-factors in transcriptional regulation
TLDR
This chapter examines the molecular mechanisms by which HOX proteins regulate transcription, with an emphasis on how they achieve specificity, through the construction of artificial HOX-responsive enhancers and the identification of naturally occurring target elements. Expand
Genome-Wide Analysis of the Binding of the Hox Protein Ultrabithorax and the Hox Cofactor Homothorax in Drosophila
TLDR
Overall, a set of direct Ubx targets in the haltere imaginal disc is defined and it is suggested that chromatin accessibility has important implications for Hox target selection and for transcription factor binding in general. Expand
In vivo Hox binding specificity revealed by systematic changes to a single cis regulatory module
TLDR
A cis regulatory module directly regulated by seven different Drosophila Hox proteins is analysed and it is found that similar regulation can be achieved by Amphioxus orthologs, suggesting these three mechanisms are conserved from insects to chordates. Expand
Dissecting the functional specificities of two Hox proteins.
TLDR
Evidence is provided that another Drosophila Hox protein, Deformed (Dfd), uses a very similar mechanism to achieve specificity in vivo, thus generalizing this mechanism and suggesting that the interaction between these DNA-binding proteins and theDNA-binding site determines the architecture of the Hox-cofactor-DNA ternary complex. Expand
Hox cofactors in vertebrate development.
TLDR
Evidence that homeodomain-containing transcription factors that pattern the body axes of animal embryos reflect a requirement for Pbx and Meis/Prep proteins as Hox cofactors is described and the possibility that other proteins may participate in the DNA-bound Hox complex, contributing to DNA-binding specificity in the absence of, or in addition to, PbX and MeIS/Prep. Expand
Selection of distinct Hox–Extradenticle interaction modes fine-tunes Hox protein activity
TLDR
Hox–PBC interaction is identified as a template for subtle regulation of Hox protein activity that may have played a major role in the diversification of H Cox protein function in development and evolution. Expand
Function and specificity of synthetic Hox transcription factors in vivo
TLDR
The results show that synthetic Scr-HD genes are sufficient for homeotic function in Drosophila and suggest that the N terminus of Scr has a role in transcriptional potency, rather than specificity, which makes it an important tool for synthetic biology. Expand
Genome-Wide Tissue-Specific Occupancy of the Hox Protein Ultrabithorax and Hox Cofactor Homothorax in Drosophila
TLDR
The first whole-genome analysis of the binding sites and target genes regulated by Ubx to specify the morphologies of the adult T3 segment of the fly is provided, suggesting that Ubx regulates many downstream transcription factors and developmental pathways in the haltere and T3 leg. Expand
Direct regulation of knot gene expression by Ultrabithorax and the evolution of cis-regulatory elements in Drosophila
TLDR
A wing-specific cis-regulatory element controlling the knot gene is identified, which is expressed in the developing Drosophila wing but not the haltere, and has two apparently functionally redundant blocks of sequences for repression by UBX, which suggests that the complete evolutionary unit of regulatory control is larger than the minimal experimentally defined control element. Expand
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References

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TLDR
It is shown that a conserved N-terminal domain of HTH directly binds to EXD in vitro, and is sufficient to induce the nuclear localization ofEXD in vivo, however, mutating a key DNA binding residue in the HTH homeodomain abolishes many of its in vivo functions. Expand
Trimeric Association of Hox and TALE Homeodomain Proteins Mediates Hoxb2 Hindbrain Enhancer Activity
TLDR
In this study, it is demonstrated that Pbx and Meis bind DNA as heterotrimeric complexes with Hoxb1 on a genetically defined Hox b2 enhancer, r4, that mediates the cross-regulatory transcriptional effects of H Coxb1 in vivo. Expand
Homeotic response elements are tightly linked to tissue-specific elements in a transcriptional enhancer of the teashirt gene.
TLDR
This work identified a tsh gene enhancer that is differentially activated by Hox proteins in epidermis and mesoderm, and proposes that local interactions between homeotic proteins and other factors effect activation of targets in proper cell types. Expand
A model for extradenticle function as a switch that changes HOX proteins from repressors to activators
TLDR
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TLDR
It is shown that a hybrid version of Ubx (Ubx-VP16), which possesses an enhanced transcriptional activation function, no longer directs A1 denticle pattern in embryonic epidermal cells, but it mimics Antp in directing T2 denticles pattern, and it can rescue the cuticular loss-of-function phenotype of Antp mutants. Expand
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TLDR
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TLDR
An 813 bp dpp enhancer is identified which is capable of driving expression of a lacZ gene in a correct pattern in the embryonic midgut and represents the smallest in vivo homeotic response element (HOMRE) identified to date. Expand
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TLDR
It appears that the strong repressive effects of BX-C proteins on Dll expression arose relatively late in insect evolution, and is suggested to have evolved within the hexapods in a complex, segment-specific manner. Expand
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TLDR
The results suggest that Exd is a specificity cofactor for the trunk Hox genes, and that the control of Exd subcellular localization is a mechanism to regulate Hox activity during development. Expand
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TLDR
It is suggested that the control mechanism of subcellular distribution of Exd found in Drosophila probably operates in other organisms as well as it is shown that mutual interactions between Exd and BX-C proteins ensure the correct amounts of interacting molecules. Expand
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