Gene expression regulated by G-actin switch
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE17105 | GEO | 2009/07/15
SECONDARY ACCESSION(S): PRJNA119785
REPOSITORIES: GEO
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Project description:We analysed the G-actin regulated transcriptome by gene expression analysis using previously characterised actin binding drugs. We found many known MAL/MRTF-dependent target genes of serum response factor (SRF) as well as unknown directly regulated genes. Experiment Overall Design: Three conditions were used for the microarray analysis: control NIH 3T3 cells, cells treated with cytochalasin D, and cells treated with latrunculin B and cytochalasin D. For each condition, three independent biological replicates were analysed.
2009-08-07 | E-GEOD-17105 | biostudies-arrayexpress
Project description:Actin has important functions in both cytoplasm and nucleus of the cell, with active nuclear transport mechanisms maintaining the cellular actin balance. Nuclear actin levels are subject to regulation during many cellular processes from cell differentiation to cancer. Here we show that nuclear actin levels increase upon differentiation of PC6.3 cells towards neuron-like cells. Photobleaching experiments demonstrate that this increase is due to decreased nuclear export of actin during cell differentiation. Increased nuclear actin levels lead to decreased nuclear localization of MRTF-A, a well-established transcription cofactor of SRF. In line with MRTF-A localization, transcriptomics analysis reveals that MRTF/SRF target gene expression is first transiently activated, but then substantially downregulated during PC6.3 cell differentiation. This study therefore describes a novel cellular context, where regulation of nuclear actin is utilized to tune MRTF/SRF target gene expression during cell differentiation.
2022-06-27 | GSE206781 | GEO
Project description:Serum response factor (SRF) is a ubiquitously expressed transcription factor that is essential for brain development and function. SRF activity is controlled by two competing classes of coactivators, myocardin-related transcription factors (MRTF) and ternary complex factors, which introduce specificity into gene expression programs. Here, we explored the MRTF-mediated regulatory mechanism in mouse cortical neurons. Using gene-reporter assays and pharmacological and genetic approaches in isolated mouse cortical neurons, we found that cyclase-associated protein 1 (CAP1) repressed neuronal MRTF-SRF activity. CAP1 promoted cytosolic retention of MRTF by controlling cytosolic G-actin levels that required its helical folded domain and its CARP domain. This function of CAP1 was not redundant with that of its homolog CAP2 and was independent of cofilin1 and actin-depolymerizing factor. Deep RNA sequencing and mass spectrometry in cerebral cortex lysates from CAP1 knockout (CAP1-KO) mice supported the in vivo relevance for the CAP1-actin-MRTF-SRF signaling axis. Our study identified CAP1 as a repressor of neuronal gene expression and led to the identification of likely MRTF-SRF target genes in the developing cerebral cortex, whose dysregulation may contribute to impaired formation of neuronal networks in CAP1-KO mice. Together with our previous studies that implicated CAP1 in actin dynamics in axonal growth cones or excitatory synapses, we established CAP1 as a crucial actin regulator in neurons.
2024-03-22 | GSE262154 | GEO
Project description:To control transcription, SRF recruits signal-regulated co-activators, the Ternary Complex Factors (TCFs) and the Myocardin-related Transcription Factors (MRTFs), which compete for a common site on its DNA-binding domain. The TCFs - SAP-1, Elk-1 and Net - are Ets proteins that link SRF activity to Ras-ERK signalling. In contrast, the two MRTFs, MRTF-A and MRTF-B, link SRF activity to Rho-actin signalling. In this novel signalling pathway, the actin-binding MRTF RPEL domain acts as a G-actin sensor, controlling MRTF nuclear accumulation in response to signal-induced depletion of the G-actin pool. Previous studies have suggested that the Ras-ERK signalling and Rho-actin pathways control specific subsets of SRF target genes. We used ChIP-seq and RNA-seq to analyse the immediate-early transcriptional response in NIH3T3 fibroblasts, using pathway-specific inhibitors to identify the contributions of Ras-ERK and Rho-actin signalling Chromatin immunoprecipitation and sequencing (ChIP-seq) in NIH3T3 fibroblast after serum stimulation in presence or absence of LatrunculinB or U0126 drugs and using antibodies against SRF, MRTF-A, MRTF-B, SAP1, ELK1, NET, Pol II, PolII S5P, PolII S2P and total H3. Validation by ChIP-PCR. Strand specific total-RNA-seq following DSN normalisation and validation by qRT-PCR from NIH3T3 stimulated by serum or Cytochalasin D in presence or absence of LatrunculinB and/or U0126 drugs.
2014-04-24 | E-GEOD-45888 | biostudies-arrayexpress
Project description:Chemokine signaling is important for the seeding of different sites by hematopoietic stem cells during development. Serum Response Factor (SRF) controls multiple genes governing adhesion and migration, mainly by recruiting members of the Myocardin-Related Transcription Factor (MRTF) family of G-actin regulated cofactors. We used vav-iCre to inactivate MRTF-SRF signaling early during hematopoietic development. In both Srf- and Mrtf-deleted animals, hematopoiesis in fetal liver and spleen is intact, but does not become established in fetal bone marrow. Srf-null HSC/Ps (hematopoietic stem/progenitor cells) fail to effectively engraft in transplantation experiments, exhibiting normal proximal signaling responses to SDF-1, but reduced adhesiveness, F-actin assembly, and reduced motility. Srf-null HSC/Ps fail to polarise in response to SDF-1, and cannot migrate through restrictive membrane pores to SDF-1 or Scf in vitro. Mrtf-null HSC/Ps were also defective in chemotactic responses to SDF-1. MRTF-SRF signaling is thus critical for the response to chemokine signaling during hematopoietic development. Strand specific RNA sequencing (RNA-seq) in sorted WT and SRF deleted LSK cells with or without a 30 minute SDF stimulation and validation by qRT-PCR
2015-03-04 | E-GEOD-63820 | biostudies-arrayexpress
Project description:To control transcription, SRF recruits signal-regulated co-activators, the Ternary Complex Factors (TCFs) and the Myocardin-related Transcription Factors (MRTFs), which compete for a common site on its DNA-binding domain. The TCFs - SAP-1, Elk-1 and Net - are Ets proteins that link SRF activity to Ras-ERK signalling. In contrast, the two MRTFs, MRTF-A and MRTF-B, link SRF activity to Rho-actin signalling. In this novel signalling pathway, the actin-binding MRTF RPEL domain acts as a G-actin sensor, controlling MRTF nuclear accumulation in response to signal-induced depletion of the G-actin pool. Previous studies have suggested that the Ras-ERK signalling and Rho-actin pathways control specific subsets of SRF target genes. We used ChIP-seq and RNA-seq to analyse the immediate-early transcriptional response in NIH3T3 fibroblasts, using pathway-specific inhibitors to identify the contributions of Ras-ERK and Rho-actin signalling
2014-04-24 | GSE45888 | GEO
Project description:Nuclear actin participates in many essential cellular processes including gene transcription, chromatic remodelling and mRNA processing. Actin shuttles into and out the nucleus through the action of dedicated transport receptors importin-9 and exportin-6, but how this transport is regulated remains unclear. Here we show that RASSF1A is a novel regulator of actin nucleocytoplasmic trafficking and is required for the active maintenance of nuclear actin levels through supporting binding of exportin-6 (XPO6) to RAN GTPase. RASSF1A (Ras association domain family 1 isoform A) is a tumor suppressor gene frequently silenced by promoter hypermethylation in all major solid cancers. Specifically, we demonstrate that endogenous RASSF1A localizes to the nuclear envelope (NE) and is required for nucleo-cytoplasmic actin transport and the concomitant regulation of Myocardin-related transcription factor A (MRTF-A), a coactivator of the transcription factor serum response factor (SRF). The RASSF1A/RAN/XPO6/nuclear actin pathway is aberrant in cancer cells where RASSF1A expression is lost and correlates with reduced MTRF/SRF activity leading to cell adhesion defects. Taken together, we have identified a previously unknown mechanism by which the nuclear actin pool is regulated and uncovered a previously unknown link of RASSF1A and MTRF/SRF in tumor suppression.
2019-05-30 | PXD011517 | Pride
Project description:Chemokine signaling is important for the seeding of different sites by hematopoietic stem cells during development. Serum Response Factor (SRF) controls multiple genes governing adhesion and migration, mainly by recruiting members of the Myocardin-Related Transcription Factor (MRTF) family of G-actin regulated cofactors. We used vav-iCre to inactivate MRTF-SRF signaling early during hematopoietic development. In both Srf- and Mrtf-deleted animals, hematopoiesis in fetal liver and spleen is intact, but does not become established in fetal bone marrow. Srf-null HSC/Ps (hematopoietic stem/progenitor cells) fail to effectively engraft in transplantation experiments, exhibiting normal proximal signaling responses to SDF-1, but reduced adhesiveness, F-actin assembly, and reduced motility. Srf-null HSC/Ps fail to polarise in response to SDF-1, and cannot migrate through restrictive membrane pores to SDF-1 or Scf in vitro. Mrtf-null HSC/Ps were also defective in chemotactic responses to SDF-1. MRTF-SRF signaling is thus critical for the response to chemokine signaling during hematopoietic development.
2015-03-04 | GSE63820 | GEO
Project description:Myocardin-related transcription factor A (MRTF-A) in complex with the serum response factor (SRF) regulates the expression of cytoskeletal genes in response to cytoplasmic and nuclear actin dynamics. Different components of nucleoskeleton, besides nuclear actin, also regulate the activity of MRTF-A. Here we extend these studies by showing that lamina-associated polypeptide 2α (Lap2α), the nucleoplasmic isoform of Lap2, is a novel regulator, and a direct binding partner of MRTF-A. Lap2α is a nucleoplasmic protein that interacts with A-type lamins and the retinoblastoma protein (pRb) and contributes to chromatin organization. Unlike other known MRTF-A regulators, Lap2α is not required for MRTF-A nucleo-cytoplasmic shuttling; it functions within the nucleus where it binds MRTF-A directly via its unique C-terminal domain prior to MRTF-A forming the complex with chromatin and SRF. Such interaction affects MRTF-A transcriptional activity since genome-wide analysis revealed reduced binding of MRTF-A to SRF target genes in Lap2α knockout cells compared to control cells that consequently led to impaired expression of target genes. Our studies therefore add another regulatory layer to the control MRTF-A-SRF-mediated gene expression, and broaden the role of Lap2α in transcriptional regulation.
2020-12-15 | GSE159370 | GEO
Project description:Myocardin-related transcription factor A (MRTF-A) in complex with the serum response factor (SRF) regulates the expression of cytoskeletal genes in response to cytoplasmic and nuclear actin dynamics. Different components of nucleoskeleton, besides nuclear actin, also regulate the activity of MRTF-A. Here we extend these studies by showing that lamina-associated polypeptide 2α (Lap2α), the nucleoplasmic isoform of Lap2, is a novel regulator, and a direct binding partner of MRTF-A. Lap2α is a nucleoplasmic protein that interacts with A-type lamins and the retinoblastoma protein (pRb) and contributes to chromatin organization. Unlike other known MRTF-A regulators, Lap2α is not required for MRTF-A nucleo-cytoplasmic shuttling; it functions within the nucleus where it binds MRTF-A directly via its unique C-terminal domain prior to MRTF-A forming the complex with chromatin and SRF. Such interaction affects MRTF-A transcriptional activity since genome-wide analysis revealed reduced binding of MRTF-A to SRF target genes in Lap2α knockout cells compared to control cells that consequently led to impaired expression of target genes. Our studies therefore add another regulatory layer to the control MRTF-A-SRF-mediated gene expression, and broaden the role of Lap2α in transcriptional regulation.
2020-12-15 | GSE159369 | GEO