Evolution of a transcriptional repression domain in an insect Hox protein

ABSTRACT The transcriptional coactivators p300 and CREB binding protein (CBP) are important regulators of the cell cycle, differentiation, and tumorigenesis. Both p300 and CBP are targeted by viral oncoproteins, are mutated in certain forms of cancer, are phosphorylated in a cell cycle-dependent manner, interact with transcription factors such as p53 and E2F, and can be found complexed with cyclinE-Cdk2 in vivo. Moreover, p300-deficient cells show defects in proliferation. Here we demonstrate that transcriptional activation by both p300 and CBP is stimulated by coexpression of the cyclin-dependent kinase inhibitor p21WAF/CIP1. Significantly this stimulation is independent of both the inherent histone acetyltransferase (HAT) activity of p300 and CBP and of the previously reported carboxyl-terminal binding site for cyclinE-Cdk2. Rather, we describe a previously uncharacterized transcriptional repression domain (CRD1) within p300. p300 transactivation is stimulated through derepression of CRD1 by p21. Significantly p21 regulation of CRD1 is dependent on the nature of the core promoter. We suggest that CRD1 provides a novel mechanism through which p300 and CBP can switch activities between the promoters of genes that stimulate growth and those that enhance cell cycle arrest.

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MyoR Modulates Cardiac Conduction by Repressing Gata4

Molecular and Cellular Biology ◽

10.1128/mcb.00860-14 ◽

2014 ◽

Vol 35 (4) ◽

pp. 649-661 ◽

Cited By ~ 5

Author(s):

John P. Harris ◽

Minoti Bhakta ◽

Svetlana Bezprozvannaya ◽

Lin Wang ◽

Christina Lubczyk ◽

...

Keyword(s):

Transcriptional Repression ◽

Atrioventricular Node ◽

Electrical Activation ◽

Cardiac Conduction ◽

Specific Gene ◽

Dependent Manner ◽

Regulatory Circuit ◽

Genetic Deletion ◽

Repression Domain ◽

Av Delay

The cardiac conduction system coordinates electrical activation through a series of interconnected structures, including the atrioventricular node (AVN), the central connection point that delays impulse propagation to optimize cardiac performance. Although recent studies have uncovered important molecular details of AVN formation, relatively little is known about the transcriptional mechanisms that regulate AV delay, the primary function of the mature AVN. We identify here MyoR as a novel transcription factor expressed in Cx30.2+cells of the AVN. We show that MyoR specifically inhibits a Cx30.2 enhancer required for AVN-specific gene expression. Furthermore, we demonstrate that MyoR interacts directly with Gata4 to mediate transcriptional repression. Our studies reveal that MyoR contains two nonequivalent repression domains. While the MyoR C-terminal repression domain inhibits transcription in a context-dependent manner, the N-terminal repression domain can function in a heterologous context to convert the Hand2 activator into a repressor. In addition, we show that genetic deletion of MyoR in mice increases Cx30.2 expression by 50% and prolongs AV delay by 13%. Taken together, we conclude that MyoR modulates a Gata4-dependent regulatory circuit that establishes proper AV delay, and these findings may have wider implications for the variability of cardiac rhythm observed in the general population.

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Human Cytomegalovirus Immediate-Early Protein IE2 Tethers a Transcriptional Repression Domain to p53

Journal of Biological Chemistry ◽

10.1074/jbc.271.7.3534 ◽

1996 ◽

Vol 271 (7) ◽

pp. 3534-3540 ◽

Cited By ~ 83

Author(s):

Hsiu-Lan Tsai ◽

Guang-Hsiung Kou ◽

Shan-Chun Chen ◽

Cheng-Wen Wu ◽

Young-Sun Lin

Keyword(s):

Human Cytomegalovirus ◽

Transcriptional Repression ◽

Immediate Early ◽

Early Protein ◽

Repression Domain

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The DEAD Box Protein DP103 Is a Regulator of Steroidogenic Factor-1

Molecular Endocrinology ◽

10.1210/mend.15.1.0580 ◽

2001 ◽

Vol 15 (1) ◽

pp. 69-79 ◽

Cited By ~ 43

Author(s):

Qinglin Ou ◽

Jean-François Mouillet ◽

Xiaomei Yan ◽

Christoph Dorn ◽

Peter A. Crawford ◽

...

Keyword(s):

Transcriptional Repression ◽

Transcriptional Activity ◽

Point Mutations ◽

Hypothalamic Nucleus ◽

Rna Helicases ◽

Interacting Protein ◽

Steroidogenic Factor 1 ◽

Dead Box ◽

The Dead ◽

Repression Domain

Abstract The nuclear receptor steroidogenic factor-1 (SF-1) is essential for development of the gonads, adrenal gland, and the ventromedial hypothalamic nucleus. It also regulates the expression of pivotal steroidogenic enzymes and other important proteins in the reproductive system. We sought to elucidate the mechanisms that govern the transcriptional activity of SF-1. We demonstrate here that a previously uncharacterized domain, located C-terminal to the DNA binding domain of SF-1, exhibits transcriptional repression function. Point mutations in this domain markedly potentiate the transcriptional activity of native SF-1. Using an SF-1 region that spans this proximal repression domain as bait in a yeast two-hybrid system, we cloned an SF-1 interacting protein that is homologous to human DP103, a member of the DEAD box family of putative RNA helicases. DP103 directly interacts with the proximal repression domain of SF-1, and mutations in this domain abrogate its interaction with DP103. DP103 is expressed predominantly in the testis and is also expressed at a lower level in other steroidogenic and nonsteroidogenic tissues. Functionally, DP103 exhibits a native transcriptional repression function that localizes to the C-terminal region of the protein and represses the activity of wild-type, but not mutant, SF-1. Together, the physical and functional interaction of DP103 with a previously unrecognized repression domain within SF-1 represents a novel mechanism for regulation of SF-1 activity.

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Mad proteins contain a dominant transcription repression domain.

Molecular and Cellular Biology ◽

10.1128/mcb.16.10.5772 ◽

1996 ◽

Vol 16 (10) ◽

pp. 5772-5781 ◽

Cited By ~ 116

Author(s):

D E Ayer ◽

C D Laherty ◽

Q A Lawrence ◽

A P Armstrong ◽

R N Eisenman

Keyword(s):

Dna Binding ◽

Transcriptional Repression ◽

Binding Domain ◽

Full Length ◽

Dna Binding Domain ◽

Interaction Domain ◽

Transcription Repression ◽

Helix Loop Helix ◽

Repression Domain

Transcription repression by the basic region-helix-loop-helix-zipper (bHLHZip) protein Mad1 requires DNA binding as a ternary complex with Max and mSin3A or mSin3B, the mammalian orthologs of the Saccharomyces cerevisiae transcriptional corepressor SIN3. The interaction between Mad1 and mSin3 is mediated by three potential amphipathic alpha-helices: one in the N terminus of Mad (mSin interaction domain, or SID) and two within the second paired amphipathic helix domain (PAH2) of mSin3A. Mutations that alter the structure of the SID inhibit in vitro interaction between Mad and mSin3 and inactivate Mad's transcriptional repression activity. Here we show that a 35-residue region containing the SID represents a dominant repression domain whose activity can be transferred to a heterologous DNA binding region. A fusion protein comprising the Mad1 SID linked to a Ga14 DNA binding domain mediates repression of minimal as well as complex promoters dependent on Ga14 DNA binding sites. In addition, the SID represses the transcriptional activity of linked VP16 and c-Myc transactivation domains. When fused to a full-length c-Myc protein, the Mad1 SID specifically represses both c-Myc's transcriptional and transforming activities. Fusions between the GAL DNA binding domain and full-length mSin3 were also capable of repression. We show that the association between Mad1 and mSin3 is not only dependent on the helical SID but is also dependent on both putative helices of the mSin3 PAH2 region, suggesting that stable interaction requires all three helices. Our results indicate that the SID is necessary and sufficient for transcriptional repression mediated by the Mad protein family and that SID repression is dominant over several distinct transcriptional activators.

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The inv(16) Fusion Protein Associates with Corepressors via a Smooth Muscle Myosin Heavy-Chain Domain

Molecular and Cellular Biology ◽

10.1128/mcb.23.2.607-619.2003 ◽

2003 ◽

Vol 23 (2) ◽

pp. 607-619 ◽

Cited By ~ 123

Author(s):

Kristie L. Durst ◽

Bart Lutterbach ◽

Tanawan Kummalue ◽

Alan D. Friedman ◽

Scott W. Hiebert

Keyword(s):

Amino Acids ◽

Smooth Muscle ◽

Fusion Protein ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Transcriptional Repression ◽

Coiled Coil ◽

Smooth Muscle Myosin ◽

Muscle Myosin ◽

Repression Domain

ABSTRACT Inversion(16) is one of the most frequent chromosomal translocations found in acute myeloid leukemia (AML), occurring in over 8% of AML cases. This translocation results in a protein product that fuses the first 165 amino acids of core binding factor β to the coiled-coil region of a smooth muscle myosin heavy chain (CBFβ/SMMHC). CBFβ interacts with AML1 to form a heterodimer that binds DNA; this interaction increases the affinity of AML1 for DNA. The CBFβ/SMMHC fusion protein cooperates with AML1 to repress the transcription of AML1-regulated genes. We show that CBFβ/SMMHC contains a repression domain in the C-terminal 163 amino acids of the SMMHC region that is required for inv(16)-mediated transcriptional repression. This minimal repression domain is sufficient for the association of CBFβ/SMMHC with the mSin3A corepressor. In addition, the inv(16) fusion protein specifically associates with histone deacetylase 8 (HDAC8). inv(16)-mediated repression is sensitive to HDAC inhibitors. We propose a model whereby the inv(16) fusion protein associates with AML1 to convert AML1 into a constitutive transcriptional repressor.

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