scholarly journals Recruitment of the NCoA/SRC-1/p160 Family of Transcriptional Coactivators by the Aryl Hydrocarbon Receptor/Aryl Hydrocarbon Receptor Nuclear Translocator Complex

2002 ◽  
Vol 22 (12) ◽  
pp. 4319-4333 ◽  
Author(s):  
Timothy V. Beischlag ◽  
Song Wang ◽  
David W. Rose ◽  
Joseph Torchia ◽  
Suzanne Reisz-Porszasz ◽  
...  

ABSTRACT The aryl hydrocarbon receptor complex heterodimeric transcription factor, comprising the basic helix-loop-helix-Per-ARNT-Sim (bHLH-PAS) domain aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator (ARNT) proteins, mediates the toxic effects of TCDD (2,3,7,8 tetrachlorodibenzo-p-dioxin). The molecular events underlying TCDD-inducible gene activation, beyond the activation of the AHRC, are poorly understood. The SRC-1/NCoA-1, NCoA-2/GRIP-1/TIF-2, and p/CIP/AIB/ACTR proteins have been shown to act as mediators of transcriptional activation. In this report, we demonstrate that SRC-1, NCoA-2, and p/CIP are capable of independently enhancing TCDD-dependent induction of a luciferase reporter gene by the AHR/ARNT dimer. Furthermore, injection of anti-SRC-1 or anti-p/CIP immunoglobulin G into mammalian cells abolishes the transcriptional activity of a TCDD-dependent reporter gene. We demonstrate by coimmunoprecipitation and by a reporter gene assay that SRC-1 and NCoA-2 but not p/CIP are capable of interacting with ARNT in vivo after transient transfection into mammalian cells, while AHR is capable of interacting with all three coactivators. We confirm the interactions of ARNT and AHR with SRC-1 with immunocytochemical techniques. Furthermore, SRC-1, NCoA-2, and p/CIP all associate with the CYP1A1 enhancer region in a TCDD-dependent fashion, as demonstrated by chromatin immunoprecipitation assays. We demonstrate by yeast two-hybrid, glutathione S-transferase pulldown, and mammalian reporter gene assays that ARNT requires its helix 2 domain but not its transactivation domain to interact with SRC-1. This indicates a novel mechanism of action for SRC-1. SRC-1 does not require its bHLH-PAS domain to interact with ARNT or AHR, but utilizes distinct domains proximal to its p300/CBP interaction domain. Taken together, these data support a role for the SRC family of transcriptional coactivators in TCDD-dependent gene regulation.

Foods ◽  
2016 ◽  
Vol 5 (1) ◽  
pp. 15 ◽  
Author(s):  
Yoshiaki Amakura ◽  
Tomoaki Tsutsumi ◽  
Morio Yoshimura ◽  
Masafumi Nakamura ◽  
Hiroshi Handa ◽  
...  

2003 ◽  
Vol 26 (4) ◽  
pp. 532-539 ◽  
Author(s):  
Yoshiaki Amakura ◽  
Tomoaki Tsutsumi ◽  
Masafumi Nakamura ◽  
Hiroko Kitagawa ◽  
Junko Fujino ◽  
...  

2004 ◽  
Vol 50 (5) ◽  
pp. 530-536 ◽  
Author(s):  
Masashi Sekimoto ◽  
Miho Iwamoto ◽  
Shoji Miyajima ◽  
Kiyomitsu Nemoto ◽  
Masakuni Degawa

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Alberto Celma ◽  
Geeta Mandava ◽  
Agneta Oskarsson ◽  
Juan Vicente Sancho ◽  
Lubertus Bijlsma ◽  
...  

Abstract Background Fresh water bodies represent less than 1% of overall amount of water on earth and ensuring their quality and sustainability is pivotal. Although several campaigns have been performed to monitor the occurrence of micropollutants by means of chemical analysis, this might not cover the whole set of chemicals present in the sample nor the potential toxic effects of mixtures of natural and anthropogenic chemicals. In this sense, by selecting relevant toxicity endpoints when performing in vitro bioanalysis, effect-based methodologies can be of help to perform a comprehensive assessment of water quality and reveal biological activities relevant to adverse health effects. However, no prior bioanalytical study was performed in wetland water samples from the Spanish Mediterranean coastline. Methods Eleven samples from relevant water bodies from the Spanish Mediterranean coastline were collected to monitor water quality on 8 toxicity endpoints. Aryl hydrocarbon receptor (AhR), androgenicity (AR+ and AR−), estrogenicity (ER+ and ER−), oxidative stress response (Nrf2) and vitamin D receptor (VDR+ and VDR−) reporter gene assays were evaluated. Results AhR was the reporter gene assay showing a more frequent response over the set of samples (activated by 9 out of 11 samples), with TCDD-eq in the range 7.7–22.2 pM. For AR, ER and VDR assays sporadic activations were observed. Moreover, no activity was observed on the Nrf2 reporter gene assay. Wastewater and street runaway streams from Valencia could be responsible for enhanced activities in one of the water inputs in the Natural Park ‘L’Albufera’. Conclusions Water quality of relevant wetlands from the Spanish Mediterranean coastline has been evaluated. The utilization of a panel of 5 different bioassays to cover for different toxicity endpoints has demonstrated to be a good tool to assess water quality.


Author(s):  
Karin Lauschke ◽  
Andreas Frederik Treschow ◽  
Mikkel Aabech Rasmussen ◽  
Nichlas Davidsen ◽  
Bjørn Holst ◽  
...  

AbstractTo test large numbers of chemicals for developmental toxicity, rapid in vitro tests with standardized readouts for automated data acquisition are needed. However, the most widely used assay, the embryonic stem cell test, relies on the counting of beating embryoid bodies by visual inspection, which is laborious and time consuming. We previously developed the PluriBeat assay based on differentiation of human induced pluripotent stem cells (hiPSC) that we demonstrated to be predictive for known teratogens at relevant concentrations using the readout of beating cardiomyocytes. Here, we report the development of a novel assay, which we term the PluriLum assay, where we have introduced a luciferase reporter gene into the locus ofNKX2.5of our hiPSC line. This enabled us to measure luminescence intensities instead of counting beating cardiomyocytes, which is less labor intensive. We established twoNKX2.5reporter cell lines and validated their pluripotency and genetic stability. Moreover, we confirmed that the genetically engineeredNKX2.5reporter cell line differentiated into cardiomyocytes with the same efficiency as the original wild-type line. We then exposed the cells to valproic acid (25–300 μM) and thalidomide (0.1–36 µM) and compared the PluriBeat readout of the cardiomyocytes with the luminescence intensity of the PluriLum assay. The results showed that thalidomide decreased luminescence intensity significantly with a higher potency and efficacy compared to the beating readout. With this, we have developed a novel hiPSC-based assay with a standardized readout that may have the potential for higher throughput screening for developmental toxicity.


2002 ◽  
Vol 76 (24) ◽  
pp. 12683-12690 ◽  
Author(s):  
Noriko Yokosawa ◽  
Shin-ichi Yokota ◽  
Toru Kubota ◽  
Nobuhiro Fujii

ABSTRACT Constitutive levels of production of STAT-1 were reduced by 10 h postinfection (p.i.) and significantly lost by 24 h p.i. in FL cells acutely infected with mumps virus (MuV). This result was consistent with that observed in previous studies and experiments with cells persistently infected with MuV (FLMT cells). There was a marked decrease in the amount of STAT-1 in cells expressing MuV accessory protein V (MuV-V). Furthermore, single amino acid substitutions in the Cys-rich region of V protein (Vc189a, Vc207a, and Vc214a) showed that each cysteine residue plays an important role in the decrease in STAT-1 production, but substitution of a histidine residue at amino acid position 203 had no effect. These events and the resultant suppression of the alpha interferon (IFN-α) response were confirmed by a luciferase reporter gene assay with five tandem repeats of the IFN-α-stimulated response element as an enhancer element of the firely luciferase gene. STAT-1 production was restored and detectable in FLMT cells treated with a proteosome inhibitor, such as MG132 or lactacystin. In the presence of MG132, ubiquitination of STAT-1 and the interaction of MuV-V with STAT-1 were demonstrated in FLMT cells by immunoprecipitation with anti-STAT-1 antibody. The same results for the interaction and ubiquitination were obtained in experiments with an expression vector for a C-terminal deletion mutant of STAT-1. The truncated STAT-1 molecules were degraded in the presence of MuV-V. Therefore, the C-terminal region (transcriptional activation and Src homology 2 domains) of STAT-1 is not necessary for its degradation caused by MuV-V. Our data suggest that MuV-V promotes ubiquitination and degradation of STAT-1.


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