scholarly journals Cardiac Tissue Enriched Factors Serum Response Factor and GATA-4 Are Mutual Coregulators

2000 ◽  
Vol 20 (20) ◽  
pp. 7550-7558 ◽  
Author(s):  
Narasimhaswamy S. Belaguli ◽  
Jorge L. Sepulveda ◽  
Vishal Nigam ◽  
Frédéric Charron ◽  
Mona Nemer ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Cardiac Tissue ◽  
Serum Response Factor ◽  
Zinc Finger Protein ◽  
Response Factor ◽  
Mads Box ◽  
Cardiovascular Tissue ◽  
Serum Response

ABSTRACT Combinatorial interaction among cardiac tissue-restricted enriched transcription factors may facilitate the expression of cardiac tissue-restricted genes. Here we show that the MADS box factor serum response factor (SRF) cooperates with the zinc finger protein GATA-4 to synergistically activate numerous myogenic and nonmyogenic serum response element (SRE)-dependent promoters in CV1 fibroblasts. In the absence of GATA binding sites, synergistic activation depends on binding of SRF to the proximal CArG box sequence in the cardiac and skeletal α-actin promoter. GATA-4's C-terminal activation domain is obligatory for synergistic coactivation with SRF, and its N-terminal domain and first zinc finger are inhibitory. SRF and GATA-4 physically associate both in vivo and in vitro through their MADS box and the second zinc finger domains as determined by protein A pullout assays and by in vivo one-hybrid transfection assays using Gal4 fusion proteins. Other cardiovascular tissue-restricted GATA factors, such as GATA-5 and GATA-6, were equivalent to GATA-4 in coactivating SRE-dependent targets. Thus, interaction between the MADS box and C4 zinc finger proteins, a novel regulatory paradigm, mediates activation of SRF-dependent gene expression.

Functional antagonism between YY1 and the serum response factor

1992 ◽  
Vol 12 (9) ◽  
pp. 4209-4214
Author(s):  
A Gualberto ◽  
D LePage ◽  
G Pons ◽  
S L Mader ◽  
K Park ◽  
...  
Keyword(s):  
Serum Response Factor ◽  
Regulatory Element ◽  
Target Sequence ◽  
Response Factor ◽  
Basal Expression ◽  
Actin Promoter ◽  
Alpha Actin ◽  
Serum Response

The rapid, transient induction of the c-fos proto-oncogene by serum growth factors is mediated by the serum response element (SRE). The SRE shares homology with the muscle regulatory element (MRE) of the skeletal alpha-actin promoter. It is not known how these elements respond to proliferative and cell-type-specific signals, but the response appears to involve the binding of the serum response factor (SRF) and other proteins. Here, we report that YY1, a multifunctional transcription factor, binds to SRE and MRE sequences in vitro. The methylation interference footprint of YY1 overlaps with that of the SRF, and YY1 competes with the SRF for binding to these DNA elements. Overexpression of YY1 repressed serum-inducible and basal expression from the c-fos promoter and repressed basal expression from the skeletal alpha-actin promoter. YY1 also repressed expression from the individual SRE and MRE sequences upstream from a TATA element. Unlike that of YY1, SRF overexpression alone did not influence the transcriptional activity of the target sequence, but SRF overexpression could reverse YY1-mediated trans repression. These data suggest that YY1 and the SRF have antagonistic functions in vivo.

scholarly journals Functional antagonism between YY1 and the serum response factor.

1992 ◽  
Vol 12 (9) ◽  
pp. 4209-4214 ◽  
Author(s):  
A Gualberto ◽  
D LePage ◽  
G Pons ◽  
S L Mader ◽  
K Park ◽  
...  
Keyword(s):  
Serum Response Factor ◽  
Regulatory Element ◽  
Target Sequence ◽  
Response Factor ◽  
Basal Expression ◽  
Actin Promoter ◽  
Alpha Actin ◽  
Serum Response

The rapid, transient induction of the c-fos proto-oncogene by serum growth factors is mediated by the serum response element (SRE). The SRE shares homology with the muscle regulatory element (MRE) of the skeletal alpha-actin promoter. It is not known how these elements respond to proliferative and cell-type-specific signals, but the response appears to involve the binding of the serum response factor (SRF) and other proteins. Here, we report that YY1, a multifunctional transcription factor, binds to SRE and MRE sequences in vitro. The methylation interference footprint of YY1 overlaps with that of the SRF, and YY1 competes with the SRF for binding to these DNA elements. Overexpression of YY1 repressed serum-inducible and basal expression from the c-fos promoter and repressed basal expression from the skeletal alpha-actin promoter. YY1 also repressed expression from the individual SRE and MRE sequences upstream from a TATA element. Unlike that of YY1, SRF overexpression alone did not influence the transcriptional activity of the target sequence, but SRF overexpression could reverse YY1-mediated trans repression. These data suggest that YY1 and the SRF have antagonistic functions in vivo.

scholarly journals Inhibition of Serum Response Factor Improves Response to Enzalutamide in Prostate Cancer

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3540
Author(s):  
R. William Watson ◽  
Haleema Azam ◽  
Claudia Aura ◽  
Niamh Russell ◽  
Janet McCormack ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Serum Response Factor ◽  
Specific Antigen ◽  
Xenograft Model ◽  
Tumour Volume ◽  
Lead Target ◽  
Response Factor ◽  
Serum Response

Castrate-resistant prostate cancer (CRPC) is challenging to treat with the androgen receptor (AR), the main target and key focus of resistance. Understanding the mechanisms of AR interaction with co-regulators will identify new therapeutic targets to overcome AR resistance mechanisms. We previously identified the serum response factor (SRF) as a lead target in an in vitro model of CRPC and showed that SRF expression in tissues of CRPC patients was associated with shorter survival. Here, we tested SRF inhibition in vitro and in vivo to assess SRF as a potential target in CRPC. Inhibition of SRF with the small-molecule inhibitor CCG1423 resulted in enhanced response to enzalutamide in vitro and reduced tumour volume of LuCaP 35CR, a CRPC patient-derived xenograft model. Nuclear localisation of AR post-CCG1423 was significantly decreased and was associated with decreased α-tubulin acetylation in vitro and decreased prostate specific antigen (PSA) levels in vivo. SRF immunoreactivity was tested in metastatic tissues from CRPC patients to investigate its role in enzalutamide response. Kaplan–Meier curves showed that high SRF expression was associated with shorter response to enzalutamide. Our study supports the use of SRF inhibitors to improve response to enzalutamide.

scholarly journals Protein Kinase Cδ Blocks Immediate-Early Gene Expression in Senescent Cells by Inactivating Serum Response Factor

2004 ◽  
Vol 24 (16) ◽  
pp. 7298-7311 ◽  
Author(s):  
Keith Wheaton ◽  
Karl Riabowol
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Serum Response Factor ◽  
Immediate Early Gene ◽  
Early Gene ◽  
Immediate Early ◽  
Response Factor ◽  
Serum Response

ABSTRACT Fibroblasts lose the ability to replicate in response to growth factors and become unable to express growth-associated immediate-early genes, including c-fos and egr-1, as they become senescent. The serum response factor (SRF), a major transcriptional activator of immediate-early gene promoters, loses the ability to bind to the serum response element (SRE) and becomes hyperphosphorylated in senescent cells. We identify protein kinase C delta (PKCδ) as the kinase responsible for inactivation of SRF both in vitro and endogenously in senescent cells. This is due to a higher level of PKCδ activity as cells age, production of the PKCδ catalytic fragment, and its nuclear localization in senescent but not in low-passage-number cells. The phosphorylation of T160 of SRF by PKCδ in vitro and in vivo led to loss of SRF DNA binding activity. Both the PKCδ inhibitor rottlerin and ectopic expression of a dominant negative form of PKCδ independently restored SRE-dependent transcription and immediate-early gene expression in senescent cells. Modulation of PKCδ activity in vivo with rottlerin or bistratene A altered senescent- and young-cell morphology, respectively. These observations support the idea that the coordinate transcriptional inhibition of several growth-associated genes by PKCδ contributes to the senescent phenotype.

scholarly journals A growth factor-induced kinase phosphorylates the serum response factor at a site that regulates its DNA-binding activity.

1993 ◽  
Vol 13 (10) ◽  
pp. 6260-6273 ◽  
Author(s):  
V M Rivera ◽  
C K Miranti ◽  
R P Misra ◽  
D D Ginty ◽  
R H Chen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Serum Response Factor ◽  
Critical Role ◽  
Response Factor ◽  
Serum Response Element ◽  
Response Element ◽  
Ribosomal S6 Kinase ◽  
Serum Response

A signaling pathway by which growth factors may induce transcription of the c-fos proto-oncogene has been characterized. Growth factor stimulation of quiescent fibroblasts activates a protein kinase cascade that leads to the rapid and transient phosphorylation of the serum response factor (SRF), a regulator of c-fos transcription. The in vivo kinetics of SRF phosphorylation and dephosphorylation parallel the activation and subsequent repression of c-fos transcription, suggesting that this phosphorylation event plays a critical role in the control of c-fos expression. The ribosomal S6 kinase pp90rsk, a growth factor-inducible kinase, phosphorylates SRF in vitro at serine 103, the site that becomes newly phosphorylated upon growth factor stimulation in vivo. Phosphorylation of serine 103 significantly enhances the affinity and rate with which SRF associates with its binding site, the serum response element, within the c-fos promoter. These results suggest a model in which the growth factor-induced phosphorylation of SRF at serine 103 contributes to the activation of c-fos transcription by facilitating the formation of an active transcription complex at the serum response element.

scholarly journals MCM1 point mutants deficient in expression of alpha-specific genes: residues important for interaction with alpha 1.

1994 ◽  
Vol 14 (4) ◽  
pp. 2534-2544 ◽  
Author(s):  
L Bruhn ◽  
G F Sprague
Keyword(s):  
Dna Binding ◽  
Serum Response Factor ◽  
Specific Gene ◽  
Response Factor ◽  
Binding Assays ◽  
Yeast Saccharomyces Cerevisiae ◽  
Coregulatory Proteins ◽  
Serum Response

Complexes formed between MCM1 and several coregulatory proteins--alpha 1, alpha 2, and STE12--serve to govern transcription of the a- and alpha-specific gene sets in the yeast Saccharomyces cerevisiae. The N-terminal third of MCM1, MCM1(1-98), which includes a segment homologous to mammalian serum response factor, is capable of performing all of the functions necessary for cell-type-specific gene regulation, including DNA binding and interaction with coregulatory proteins. To explore the mechanisms by which MCM1(1-98) functions, we isolated point mutants that are specifically deficient in alpha-specific gene expression in vivo, anticipating that many of the mutants would be impaired for interaction with alpha 1. Indeed, in vitro DNA binding assays revealed that a substantial number of the mutants were specifically defective in the ability to bind cooperatively with alpha 1. Two other mutant classes were also found. One class, exemplified most clearly by substitutions at residues 22 and 27, exhibited a general defect in DNA binding. The second class, exemplified by substitutions at residues 33 and 41, was proficient at DNA binding and interaction with alpha 1 in vitro, suggesting that these mutants may be defective in achieving an alpha 1-mediated conformational change required for transcription activation in vivo. Most of the mutants defective for interaction with alpha 1 had substitutions within residues 69 to 81, which correspond to a region of serum response factor important for interaction with its coregulatory proteins. A subset of the mutants with changes in this region were also defective in the ability to bind with STE12 to DNA from an a-specific gene, suggesting that a common region of MCM1(1-98) mediates interaction with both alpha 1 and STE12. This region of MCM1 does not seem to constitute an independent domain of the protein, however, because some substitutions within this region affected DNA binding. Only two of the MCM1(1-98) point mutants showed significant defects in the ability to form complexes with alpha 2, suggesting that the mechanism by which MCM1 interacts with alpha 2 is distinct from that by which it interacts with alpha 1 and STE12.

scholarly journals Serum response factor is essential for synaptic maturation in the hippocampus

2020 ◽  
Author(s):  
Anna Krysiak ◽  
Matylda Roszkowska ◽  
Lena Majchrowicz ◽  
Anna Beroun ◽  
Piotr Michaluk ◽  
...  
Keyword(s):  
Dendritic Spines ◽  
Serum Response Factor ◽  
Imaging Techniques ◽  
Expression Patterns ◽  
Autism Spectrum ◽  
Response Factor ◽  
Serum Response

AbstractDisturbances of gene expression patterns that occur during brain development can severely affect signal transmission, connectivity, and plasticity—key features that underlie memory formation and storage in neurons. Abnormalities at the molecular level can manifest as changes in the structural and functional plasticity of dendritic spines that harbor excitatory synapses. This can lead to such developmental neuropsychiatric conditions as Autism spectrum disorders, intellectual disabilities, and schizophrenia. The present study investigated the role of the major transcriptional regulator serum response factor (SRF) in synapse maturation and its impact on behavioral phenotypes. Using in vitro and in vivo models of early postnatal SRF deletion, we studied its influence on key morphological and physiological hallmarks of spine development. The elimination of SRF in developing neurons resulted in a phenotype of immature dendritic spines and impairments in excitatory transmission. Moreover, using a combination of molecular and imaging techniques, we showed that SRF-depleted neurons exhibited a lower level of specific glutamate receptor mRNAs and a decrease in their surface expression. Additionally, the early postnatal elimination of SRF in hippocampal CA1 excitatory neurons caused spine immaturity and a specific social deficit that is frequently observed in autism patients. Altogether, our data suggest that the regulation of structural and functional dendritic spine maturation begins at the stage of gene transcription, which underpins the crucial role of such transcription factors as SRF. Moreover, disturbances of the postnatal expression of SRF translate to behavioral changes in adult animals.

A growth factor-induced kinase phosphorylates the serum response factor at a site that regulates its DNA-binding activity

1993 ◽  
Vol 13 (10) ◽  
pp. 6260-6273
Author(s):  
V M Rivera ◽  
C K Miranti ◽  
R P Misra ◽  
D D Ginty ◽  
R H Chen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Serum Response Factor ◽  
Critical Role ◽  
Response Factor ◽  
Serum Response Element ◽  
Response Element ◽  
Ribosomal S6 Kinase ◽  
Serum Response

A signaling pathway by which growth factors may induce transcription of the c-fos proto-oncogene has been characterized. Growth factor stimulation of quiescent fibroblasts activates a protein kinase cascade that leads to the rapid and transient phosphorylation of the serum response factor (SRF), a regulator of c-fos transcription. The in vivo kinetics of SRF phosphorylation and dephosphorylation parallel the activation and subsequent repression of c-fos transcription, suggesting that this phosphorylation event plays a critical role in the control of c-fos expression. The ribosomal S6 kinase pp90rsk, a growth factor-inducible kinase, phosphorylates SRF in vitro at serine 103, the site that becomes newly phosphorylated upon growth factor stimulation in vivo. Phosphorylation of serine 103 significantly enhances the affinity and rate with which SRF associates with its binding site, the serum response element, within the c-fos promoter. These results suggest a model in which the growth factor-induced phosphorylation of SRF at serine 103 contributes to the activation of c-fos transcription by facilitating the formation of an active transcription complex at the serum response element.

scholarly journals Serum response factor is an essential transcription factor in megakaryocytic maturation

Blood ◽  
2010 ◽  
Vol 116 (11) ◽  
pp. 1942-1950 ◽  
Author(s):  
Stephanie Halene ◽  
Yuan Gao ◽  
Katherine Hahn ◽  
Stephanie Massaro ◽  
Joseph E. Italiano ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Serum Response Factor ◽  
Critical Role ◽  
Response Factor ◽  
Megakaryoblastic Leukemia ◽  
Serum Response ◽  
Essential Transcription Factor

Abstract Serum response factor (Srf) is a MADS–box transcription factor that is critical for muscle differentiation. Its function in hematopoiesis has not yet been revealed. Mkl1, a cofactor of Srf, is part of the t(1;22) translocation in acute megakaryoblastic leukemia, and plays a critical role in megakaryopoiesis. To test the role of Srf in megakaryocyte development, we crossed Pf4-Cre mice, which express Cre recombinase in cells committed to the megakaryocytic lineage, to SrfF/F mice in which functional Srf is no longer expressed after Cre-mediated excision. Pf4-Cre/SrfF/F knockout (KO) mice are born with normal Mendelian frequency, but have significant macrothrombocytopenia with approximately 50% reduction in platelet count. In contrast, the BM has increased number and percentage of CD41+ megakaryocytes (WT: 0.41% ± 0.06%; KO: 1.92% ± 0.12%) with significantly reduced ploidy. KO mice show significantly increased megakaryocyte progenitors in the BM by FACS analysis and CFU-Mk. Megakaryocytes lacking Srf have abnormal stress fiber and demarcation membrane formation, and platelets lacking Srf have abnormal actin distribution. In vitro and in vivo assays reveal platelet function defects in KO mice. Critical actin cytoskeletal genes are down-regulated in KO megakaryocytes. Thus, Srf is required for normal megakaryocyte maturation and platelet production partly because of regulation of cytoskeletal genes.

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