Cell-type specificity of short-range transcriptional repressors

Ryu, Jae Ryeon; Olson, L. Karl; Arnosti, David N.

doi:10.1073/pnas.231394998

Cited by 12 publications

(15 citation statements)

References 53 publications

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“…In these experiments, dCtBP was efficiently expressed and showed a nuclear localization (data not shown). Moreover, the dCtBP form used here was found to be functional in S2 cells because in a different promoter context, its overexpression was shown to interfere with activation (22). In good agreement with these results, co-transfection of increasing amounts of RNAi directed against dCtBP showed no significant effect on the ability of TTK69 to repress GAGA-mediated activation of the eve promoter (Fig.…”

Section: Repression By Ttk69 Of Gaga-dependent Activation Is Not Affesupporting

confidence: 81%

Repression by TTK69 of GAGA-mediated Activation Occurs in the Absence of TTK69 Binding to DNA and Solely Requires the Contribution of the POZ/BTB Domain of TTK69

Pagans

Piñeyro²,

Kosoy³

et al. 2004

Journal of Biological Chemistry

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tramtrack 69 (TTK69) is known to repress GAGA-mediated activation of the eve promoter in S2 cells. Here, we show that repression by TTK69 occurs in the absence of bona fide TTK69-binding sites on the template, indicating that it does not require the binding of TTK69 to DNA. Consistent with this interpretation, the POZ/BTB domain of TTK69, which does not bind DNA, is sufficient for repression. Moreover, a fusion protein in which the POZ/BTB domain of GAGA is replaced by that of TTK69 is not capable of activating the eve promoter but efficiently represses GAGA-dependent activation. Repression involves GAGA-TTK69 interaction because TTK69 is not capable of repressing basal transcription. Most probably, GAGA-TTK69 interaction occurs at the promoter because GAGA⅐TTK69 complexes are fully competent in binding DNA in vitro. Our results also show that repression by TTK69 of GAGA-dependent activation of the eve promoter is not mediated by any of the co-repressors known to interact with TTK69 (dMi2 or C-terminal binding protein) or by trichostatin A-sensitive histone deacetylases. Altogether, these observations strongly suggest that the binding of TTK69 prevents the interaction of GAGA with the transcription machinery and, therefore, compromises its activation potential.

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Section: Repression By Ttk69 Of Gaga-dependent Activation Is Not Affesupporting

confidence: 81%

Repression by TTK69 of GAGA-mediated Activation Occurs in the Absence of TTK69 Binding to DNA and Solely Requires the Contribution of the POZ/BTB Domain of TTK69

Pagans

Piñeyro²,

Kosoy³

et al. 2004

Journal of Biological Chemistry

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“…However, this system is not efficient in mammalian cells. For this reason, and based on the knowledge acquired about how TetR binds to its target operator, several chimeric versions of TetR fused to eukaryotic regulatory domains were constructed, such as the acidic activation domain (tTA) (22,115,403) and repression domains (tTS) (33,336). Based on hybrid transregulators, transgenic mice able to produce diphtheria toxin or the regulated expression of Shiga toxin ␤ to induce apoptosis in mammalian fibroblastic cells were obtained.…”

Section: Biotechnological Applications and Future Prospectsmentioning

confidence: 99%

The TetR Family of Transcriptional Repressors

Ramos

Martínez-Bueno

Molina‐Henares

et al. 2005

Microbiol Mol Biol Rev

978

1,133

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We have developed a general profile for the proteins of the TetR family of repressors. The stretch that best defines the profile of this family is made up of 47 amino acid residues that correspond to the helix-turn-helix DNA binding motif and adjacent regions in the three-dimensional structures of TetR, QacR, CprB, and EthR, four family members for which the function and three-dimensional structure are known. We have detected a set of 2,353 nonredundant proteins belonging to this family by screening genome and protein databases with the TetR profile. Proteins of the TetR family have been found in 115 genera of gram-positive, α-, β-, and γ-proteobacteria, cyanobacteria, and archaea. The set of genes they regulate is known for 85 out of the 2,353 members of the family. These proteins are involved in the transcriptional control of multidrug efflux pumps, pathways for the biosynthesis of antibiotics, response to osmotic stress and toxic chemicals, control of catabolic pathways, differentiation processes, and pathogenicity. The regulatory network in which the family member is involved can be simple, as in TetR (i.e., TetR bound to the target operator represses tetA transcription and is released in the presence of tetracycline), or more complex, involving a series of regulatory cascades in which either the expression of the TetR family member is modulated by another regulator or the TetR family member triggers a cell response to react to environmental insults. Based on what has been learned from the cocrystals of TetR and QacR with their target operators and from their three-dimensional structures in the absence and in the presence of ligands, and based on multialignment analyses of the conserved stretch of 47 amino acids in the 2,353 TetR family members, two groups of residues have been identified. One group includes highly conserved positions involved in the proper orientation of the helix-turn-helix motif and hence seems to play a structural role. The other set of less conserved residues are involved in establishing contacts with the phosphate backbone and target bases in the operator. Information related to the TetR family of regulators has been updated in a database that can be accessed at www.bactregulators.org

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“…A different strategy was adopted by engineering a tc‐controlled trans ‐silencer protein [81]. Fusion of the KRAB domain of Kox1 [97] to TetR yielded a hybrid protein called tTS, that not only substantially repressed basal transcription from P tet ‐1 even if the tet operators were located 3 kbp distant from the minimal promoter, but also efficiently down‐regulated gene expression from a CMV enhancer‐driven P tet ‐1 [83]. This strategy therefore appears to be more versatile in coping with unwanted target gene expression than the promoter adaptation proposed above.…”

Section: Gene Regulation By Tetr‐based Transregulatorsmentioning

confidence: 99%

“…3A; tTA or Tet-Off) [75][76][77][78][79][80] or a repression domain ( Fig. 3B; tTS) [81][82][83]. The transactivator tTA directs expression from a tc-dependent promoter that contains seven repeats of a tetO 2 element from the transposon Tn10.…”

Section: Gene Regulation By Tetr-based Transregulatorsmentioning

confidence: 99%

“…In addition and in contrast to tTA, the tc-dependent silencing of complex promoters offers the unique possibility of reversibly down-regulating the expression of cellular genes on top of their normal regulation. The KRAB domain is inactive in S. cerevisiae and Drosophila where it was replaced with repression domains from the proteins SSN6 [82], knirps, giant or dCtBP [83].…”

Section: Gene Regulation By Tetr-based Transregulatorsmentioning

confidence: 99%

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Gene regulation by tetracyclines

Berens¹,

Hillen²

2003

European Journal of Biochemistry

219

184

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The Tet repressor protein (TetR) regulates transcription of a family of tetracycline (tc) resistance determinants in Gram-negative bacteria. The resistance protein TetA, a membrane-spanning H + -[tcAEM] + antiporter, must be sensitively regulated because its expression is harmful in the absence of tc, yet it has to be expressed before the drugs' concentration reaches cytoplasmic levels inhibitory for protein synthesis. Consequently, TetR shows highly specific tetO binding to reduce basal expression and high affinity to tc to ensure sensitive induction. Tc can cross biological membranes by diffusion enabling this inducer to penetrate the majority of cells. These regulatory and pharmacological properties are the basis for application of TetR to selectively control the expression of single genes in lower and higher eukaryotes. TetR can be used for that purpose in some organisms without further modifications. In mammals and in a large variety of other organisms, however, eukaryotic transcriptional activator or repressor domains are fused to TetR to turn it into an efficient regulator. Mechanistic understanding and the ability to engineer and screen for mutants with specific properties allow tailoring of the DNA recognition specificity, the response to inducer tc and the dimerization specificity of TetR-based eukaryotic regulators. This review provides an overview of the TetR properties as they evolved in bacteria, the functional modifications necessary to transform it into a convenient, specific and efficient regulator for use in eukaryotes and how the interplay between structure ) function studies in bacteria and specific requirements of particular applications in eukaryotes have made it a versatile and highly adaptable regulatory system.

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Cell-type specificity of short-range transcriptional repressors

Cited by 12 publications

References 53 publications

Repression by TTK69 of GAGA-mediated Activation Occurs in the Absence of TTK69 Binding to DNA and Solely Requires the Contribution of the POZ/BTB Domain of TTK69

Repression by TTK69 of GAGA-mediated Activation Occurs in the Absence of TTK69 Binding to DNA and Solely Requires the Contribution of the POZ/BTB Domain of TTK69

The TetR Family of Transcriptional Repressors

Gene regulation by tetracyclines

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