scholarly journals Attenuation of Glucocorticoid Signaling through Targeted Degradation of p300 via the 26S Proteasome Pathway

2002 ◽  
Vol 16 (12) ◽  
pp. 2819-2827 ◽  
Author(s):  
Qiao Li ◽  
Anna Su ◽  
Jihong Chen ◽  
Yvonne A. Lefebvre ◽  
Robert J. G. Haché
Keyword(s):  
Gene Expression ◽  
Glucocorticoid Receptor ◽  
Sodium Butyrate ◽  
Steroid Receptor ◽  
26S Proteasome ◽  
Regulatory Control ◽  
Specific Gene ◽  
Control Of Gene Expression ◽  
Steroid Receptor Coactivator ◽  
Proteasome Pathway

Abstract The effects of acetylation on gene expression are complex, with changes in chromatin accessibility intermingled with direct effects on transcriptional regulators. For the nuclear receptors, both positive and negative effects of acetylation on specific gene transcription have been observed. We report that p300 and steroid receptor coactivator 1 interact transiently with the glucocorticoid receptor and that the acetyltransferase activity of p300 makes an important contribution to glucocorticoid receptor-mediated transcription. Treatment of cells with the deacetylase inhibitor, sodium butyrate, inhibited steroid-induced transcription and altered the transient association of glucocorticoid receptor with p300 and steroid receptor coactivator 1. Additionally, sustained sodium butyrate treatment induced the degradation of p300 through the 26S proteasome pathway. Treatment with the proteasome inhibitor MG132 restored both the level of p300 protein and the transcriptional response to steroid over 20 h of treatment. These results reveal new levels for the regulatory control of gene expression by acetylation and suggest feedback control on p300 activity.

scholarly journals A Floxed exon (Flexon) approach to Cre-mediated conditional gene expression

2021 ◽  
Author(s):  
Justin M Shaffer ◽  
Iva Greenwald
Keyword(s):  
Gene Expression ◽  
Specific Protein ◽  
Specific Gene ◽  
Coding Region ◽  
Specific Expression ◽  
Control Of Gene Expression ◽  
Tissue Specific ◽  
Nonsense Mediated Decay ◽  
Conditional Gene Expression ◽  
Stop Cassette

Conditional gene expression allows for genes to be manipulated and lineages to be marked during development. In the established "lox-stop-lox" approach, Cre-mediated tissue-specific gene expression is achieved by excising the stop cassette, a lox-flanked translational stop that is inserted into the 5' untranslated region of a gene to halt its expression. Although lox-stop-lox has been successfully used in many experimental systems, the design of traditional stop cassettes also has common issues and limitations. Here, we describe the Floxed exon (Flexon), a stop cassette within an artificial exon that can be inserted flexibly into the coding region of any gene to cause premature termination of translation and nonsense-mediated decay of the mRNA. We demonstrate its efficacy in C. elegans by showing that, when promoters that cause weak and/or transient cell-specific expression are used to drive Cre in combination with a gfp(flexon) transgene, strong and sustained expression is obtained in specific lineages. We also describe several potential additional applications for using Flexon for developmental studies, including more precise control of gene expression using intersectional methods, tissue-specific protein degradation or RNAi, and generation of genetic mosaics. The Flexon approach should be feasible in any system where any site-specific recombination-based method may be applied.

scholarly journals Intronic enhancers regulate the expression of genes involved in tissue-specific functions and homeostasis

2020 ◽  
Author(s):  
Beatrice Borsari ◽  
Pablo Villegas-Mirón ◽  
Hafid Laayouni ◽  
Alba Segarra-Casas ◽  
Jaume Bertranpetit ◽  
...  
Keyword(s):  
Gene Expression ◽  
Embryonic Stem ◽  
Gene Expression Pattern ◽  
Specific Gene ◽  
Control Of Gene Expression ◽  
Tissue Specific ◽  
Tissue Specific Gene ◽  
Specific Gene Expression ◽  
Expression Of Genes ◽  
Genomic Location

AbstractTissue function and homeostasis reflect the gene expression signature by which the combination of ubiquitous and tissue-specific genes contribute to the tissue maintenance and stimuli-responsive function. Enhancers are central to control this tissue-specific gene expression pattern. Here, we explore the correlation between the genomic location of enhancers and their role in tissue-specific gene expression. We found that enhancers showing tissue-specific activity are highly enriched in intronic regions and regulate the expression of genes involved in tissue-specific functions, while housekeeping genes are more often controlled by intergenic enhancers. Notably, an intergenic-to-intronic active enhancers continuum is observed in the transition from developmental to adult stages: the most differentiated tissues present higher rates of intronic enhancers, while the lowest rates are observed in embryonic stem cells. Altogether, our results suggest that the genomic location of active enhancers is key for the tissue-specific control of gene expression.

scholarly journals Transcriptional Regulation by Steroid Receptor Coactivator Phosphorylation

2005 ◽  
Vol 26 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Ray-Chang Wu ◽  
Carolyn L. Smith ◽  
Bert W. O’Malley
Keyword(s):  
Transcription Factors ◽  
Posttranslational Modifications ◽  
Transcriptional Activation ◽  
Regulation Of Gene Expression ◽  
Gene Activation ◽  
Steroid Receptor ◽  
Tissue Type ◽  
Specific Gene ◽  
Steroid Receptor Coactivator ◽  
Cell Tissue

The basic mechanisms underlying ligand-dependent transcriptional activation by nuclear receptors (NRs) require the sequential recruitment of various coactivators. Increasing numbers of coactivators have been identified in recent years, and both biochemical and genetic studies demonstrate that these coactivators are differentially used by transcription factors, including NRs, in a cell/tissue type- and promoter-specific manner. However, the molecular basis underlying this specificity remains largely unknown. Recently, NRs and coregulators were shown to be targets of posttranslational modifications activated by diverse cellular signaling pathways. It is argued that posttranslational modifications of these proteins provide the basis for a combinatorial code required for specific gene activation by NRs and coactivators, and that this code also enables coactivators to efficiently stimulate the activity of other classes of transcription factors. In this review, we will focus on coactivators and discuss the recent progress in understanding the role of phosphorylation of the steroid receptor coactivator family and the potential ramifications of this posttranslational modification for regulation of gene expression.

scholarly journals Reduction of Coactivator Expression by Antisense Oligodeoxynucleotides Inhibits ERα Transcriptional Activity and MCF-7 Proliferation

2002 ◽  
Vol 16 (2) ◽  
pp. 253-270 ◽  
Author(s):  
Ilaria T. R. Cavarretta ◽  
Ratna Mukopadhyay ◽  
David M. Lonard ◽  
Lex M. Cowsert ◽  
C. Frank Bennett ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activity ◽  
Steroid Receptors ◽  
Biological Effects ◽  
Steroid Receptor ◽  
Transient Transfection ◽  
Antisense Oligodeoxynucleotides ◽  
Steroid Receptor Coactivator ◽  
Mcf 7

Abstract Steroid receptor RNA activator (SRA) is a novel coactivator for steroid receptors that acts as an RNA molecule, whereas steroid receptor coactivator (SRC) family members, such as steroid receptor coactivator-1 (SRC-1) and transcriptional intermediary factor 2 (TIF2) exert their biological effects as proteins. Individual overexpression of each of these coactivators, which can form multimeric complexes in vivo, results in stimulated ERα transcriptional activity in transient transfection assays. However there is no information on the consequences of reducing SRC-1, TIF2, or SRA expression, singly or in combination, on ERα transcriptional activity. We therefore developed antisense oligodeoxynucleotides (asODNs) to SRA, SRC-1, and TIF2 mRNAs, which rapidly and specifically reduced the expression of each of these coactivators. ERα-dependent gene expression was reduced in a dose-dependent fashion by up to 80% in cells transfected with these oligonucleotides. Furthermore, treatment of cells with combinations of SRA, SRC-1, and TIF2 asODNs reduced ERα transcriptional activity to an extent greater than individual asODN treatment alone, suggesting that these coactivators cooperate, in at least an additive fashion, to activate ERα-dependent target gene expression. Finally, treatment of MCF-7 cells with asODN against SRC-1 and TIF2 revealed a requirement of these coactivators, but not SRA, for hormone-dependent DNA synthesis and induction of estrogen-dependent pS2 gene expression, indicating that SRA and SRC family coactivators can fulfill specific functional roles. Taken together, we have developed a rapid method to reduce endogenous coactivator expression that enables an assessment of the in vivo role of specific coactivators on ERα biological action and avoids potential artifacts arising from overexpression of coactivators in transient transfection assays.

scholarly journals Nuclear Integration of Glucocorticoid Receptor and Nuclear Factor-κB Signaling by CREB-binding Protein and Steroid Receptor Coactivator-1

1998 ◽  
Vol 273 (45) ◽  
pp. 29291-29294 ◽  
Author(s):  
Kelly-Ann Sheppard ◽  
Kathleen M. Phelps ◽  
Amy J. Williams ◽  
Dimitris Thanos ◽  
Christopher K. Glass ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Binding Protein ◽  
Steroid Receptor ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Creb Binding Protein ◽  
Steroid Receptor Coactivator
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