scholarly journals Regulatory role of MEF2D in serum induction of the c-jun promoter.

1995 ◽  
Vol 15 (6) ◽  
pp. 2907-2915 ◽  
Author(s):  
T H Han ◽  
R Prywes
Keyword(s):  
Dna Binding ◽  
Reporter Gene ◽  
Hela Cells ◽  
Serum Response Factor ◽  
Common Mechanism ◽  
Response Factor ◽  
3T3 Cells ◽  
Nih 3T3 ◽  
Serum Response ◽  
Nih 3T3 Cells

Serum induction of c-jun expression in HeLa cells requires a MEF2 site at -59 in the c-jun promoter. MEF2 sites, found in many muscle-specific enhancers, are bound by a family of transcription factors, MEF2A through -D, which are related to serum response factor in their DNA binding domains. We have found that MEF2D is the predominant protein in HeLa cells that binds to the c-jun MEF2 site. Serum induction of a MEF2 reporter gene was not observed in a line of NIH 3T3 cells which contain low MEF2 site binding activity. Transfection of MEF2D into NIH 3T3 cells reconstituted serum induction, demonstrating that MEF2D is required for the serum response. Deletion analysis of MEF2D showed that its DNA binding domain, when fused to a heterologous transcriptional activation domain, was sufficient for serum induction of a MEF2 reporter gene. This is the domain homologous to that in the serum response factor which is required for serum induction of the c-fos serum response element, suggesting that serum regulation of c-fos and c-jun may share a common mechanism.

scholarly journals Cell-specific regulation of oncogene-responsive sequences of the c-fos promoter

1991 ◽  
Vol 11 (10) ◽  
pp. 5381-5387
Author(s):  
A Gutman ◽  
C Wasylyk ◽  
B Wasylyk
Keyword(s):  
Hela Cells ◽  
Serum Response Factor ◽  
Tumor Promoter ◽  
3T3 Cells ◽  
Carg Box ◽  
Specific Regulation ◽  
Nih 3T3 ◽  
Serum Response ◽  
Nih 3T3 Cells

We have identified oncogene-responsive sequences in the human c-fos promoter that mediate induction of transcription by several nonnuclear oncoproteins and the tumor promoter TPA. These sequences are regulated in a cell-specific manner. (i) In NIH 3T3 cells, the CArG box of the c-fos promoter is sufficient to mediate activation by oncogenes. (ii) In contrast, in HeLa cells, additional flanking sequences are also required, including the outer arm of the serum response element and the FAP site. We also show that the serum response factor, which binds to the CArG box, activates transcription in vivo in NIH 3T3 cells but not in HeLa cells. Finally, we present evidence that the intracellular level of the c-Fos protein could be a major determinant of cell-specific regulation of these oncogene-responsive elements of the c-fos promoter.

scholarly journals Cell-specific regulation of oncogene-responsive sequences of the c-fos promoter.

1991 ◽  
Vol 11 (10) ◽  
pp. 5381-5387 ◽  
Author(s):  
A Gutman ◽  
C Wasylyk ◽  
B Wasylyk
Keyword(s):  
Hela Cells ◽  
Serum Response Factor ◽  
Tumor Promoter ◽  
3T3 Cells ◽  
Carg Box ◽  
Specific Regulation ◽  
Nih 3T3 ◽  
Serum Response ◽  
Nih 3T3 Cells

We have identified oncogene-responsive sequences in the human c-fos promoter that mediate induction of transcription by several nonnuclear oncoproteins and the tumor promoter TPA. These sequences are regulated in a cell-specific manner. (i) In NIH 3T3 cells, the CArG box of the c-fos promoter is sufficient to mediate activation by oncogenes. (ii) In contrast, in HeLa cells, additional flanking sequences are also required, including the outer arm of the serum response element and the FAP site. We also show that the serum response factor, which binds to the CArG box, activates transcription in vivo in NIH 3T3 cells but not in HeLa cells. Finally, we present evidence that the intracellular level of the c-Fos protein could be a major determinant of cell-specific regulation of these oncogene-responsive elements of the c-fos promoter.

scholarly journals Leukemia-Related Transcription Factor TEL Is Negatively Regulated through Extracellular Signal-Regulated Kinase-Induced Phosphorylation

2004 ◽  
Vol 24 (8) ◽  
pp. 3227-3237 ◽  
Author(s):  
Kazuhiro Maki ◽  
Honoka Arai ◽  
Kazuo Waga ◽  
Ko Sasaki ◽  
Fumihiko Nakamura ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Dominant Negative Effect ◽  
Phosphorylation Sites ◽  
3T3 Cells ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

ABSTRACT TEL is an ETS family transcription factor that possesses multiple putative mitogen-activated protein kinase phosphorylation sites. We here describe the functional regulation of TEL via ERK pathways. Overexpressed TEL becomes phosphorylated in vivo by activated ERK. TEL is also directly phosphorylated in vitro by ERK. The inducible phosphorylation sites are Ser213 and Ser257. TEL binds to a common docking domain in ERK. In vivo ERK-dependent phosphorylation reduces trans-repressional and DNA-binding abilities of TEL for ETS-binding sites. A mutant carrying substituted glutamates on both Ser213 and Ser257 functionally mimics hyperphosphorylated TEL and also shows a dominant-negative effect on TEL-induced transcriptional suppression. Losing DNA-binding affinity through phosphorylation but heterodimerizing with unmodified TEL could be an underlying mechanism. Moreover, the glutamate mutant dominantly interferes with TEL-induced erythroid differentiation in MEL cells and growth suppression in NIH 3T3 cells. Finally, endogenous TEL is dephosphorylated in parallel with ERK inactivation in differentiating MEL cells and is phosphorylated through ERK activation in Ras-transformed NIH 3T3 cells. These data indicate that TEL is a constituent downstream of ERK in signal transduction systems and is physiologically regulated by ERK in molecular and biological features.

scholarly journals Dominant Negative Murine Serum Response Factor: Alternative Splicing within the Activation Domain Inhibits Transactivation of Serum Response Factor Binding Targets

1999 ◽  
Vol 19 (7) ◽  
pp. 4582-4591 ◽  
Author(s):  
Narasimhaswamy S. Belaguli ◽  
Wei Zhou ◽  
Thuy-Hanh T. Trinh ◽  
Mark W. Majesky ◽  
Robert J. Schwartz
Keyword(s):  
Dna Binding ◽  
Serum Response Factor ◽  
Smooth Muscles ◽  
Dominant Negative ◽  
C2c12 Cells ◽  
Luciferase Reporter ◽  
Response Factor ◽  
Activation Domain ◽  
Alternatively Spliced ◽  
Serum Response

ABSTRACT Primary transcripts encoding the MADS box superfamily of proteins, such as MEF2 in animals and ZEMa in plants, are alternatively spliced, producing several isoformic species. We show here that murine serum response factor (SRF) primary RNA transcripts are alternatively spliced at the fifth exon, deleting approximately one-third of the C-terminal activation domain. Among the different muscle types examined, visceral smooth muscles have a very low ratio of SRFΔ5 to SRF. Increased levels of SRFΔ5 correlates well with reduced smooth muscle contractile gene activity within the elastic aortic arch, suggesting important biological roles for differential expression of SRFΔ5 variant relative to wild-type SRF. SRFΔ5 forms DNA binding-competent homodimers and heterodimers. SRFΔ5 acts as a naturally occurring dominant negative regulatory mutant that blocks SRF-dependent skeletal α-actin, cardiac α-actin, smooth α-actin, SM22α, and SRF promoter-luciferase reporter activities. Expression of SRFΔ5 interferes with differentiation of myogenic C2C12 cells and the appearance of skeletal α-actin and myogenin mRNAs. SRFΔ5 repressed the serum-induced activity of the c-fos serum response element. SRFΔ5 fused to the yeast Gal4 DNA binding domain displayed low transcriptional activity, which was complemented by overexpression of the coactivator ATF6. These results indicate that the absence of exon 5 might be bypassed through recruitment of transcription factors that interact with extra-exon 5 regions in the transcriptional activating domain. The novel alternatively spliced isoform of SRF, SRFΔ5, may play an important regulatory role in modulating SRF-dependent gene expression.

scholarly journals Recruitment of the tinman homolog Nkx-2.5 by serum response factor activates cardiac alpha-actin gene transcription.

1996 ◽  
Vol 16 (11) ◽  
pp. 6372-6384 ◽  
Author(s):  
C Y Chen ◽  
R J Schwartz
Keyword(s):  
Dna Binding ◽  
Serum Response Factor ◽  
Binding Activity ◽  
Dominant Negative ◽  
Actin Gene ◽  
Response Factor ◽  
Dna Binding Activity ◽  
Actin Promoter ◽  
Alpha Actin ◽  
Serum Response

We recently showed that the cardiogenic homeodomain factor Nkx-2.5 served as a positive acting accessory factor for serum response factor (SRF) and that together they provided strong transcriptional activation of the cardiac alpha-actin promoter, depending upon intact serum response elements (SREs) (C. Y. Chen, J. Croissant, M. Majesky, S. Topouz, T. McQuinn, M. J. Frankovsky, and R. J. Schwartz, Dev. Genet. 19:119-130, 1996). As shown here, Nkx-2.5 and SRF collaborated to activate the endogenous murine cardiac alpha-actin gene in 10T1/2 fibroblasts by a mechanism in which SRF recruited Nkx-2.5 to the alpha-actin promoter. Activation of a truncated promoter consisting of the proximal alpha-actin SRE1 occurred even when Nkx-2.5 DNA-binding activity was blocked by a point mutation in the third helix of its homeodomain. Investigation of protein-protein interactions showed that Nkx-2.5 was bound to SRF in the absence of DNA in soluble protein complexes retrieved from cardiac myocyte nuclei but could also be detected in coassociated binding complexes on the proximal SRE1. Recruitment of Nkx-2.5 to an SRE depended upon SRF DNA-binding activity and was blocked by the dominant negative SRFpm1 mutant, which allowed for dimerization of SRF monomers but prevented DNA binding. Interactive regions shared by Nkx-2.5 and SRF were mapped to N-terminal/helix I and helix II/helix III regions of the Nkx-2.5 homeodomain and to the N-terminal extension of the MADS box. Our study suggests that physical association between Nkx-2.5 and SRF is one way that cardiac specified genes are activated in cardiac cell lineages.

scholarly journals Enhancement of Serum-response Factor-dependent Transcription and DNA Binding by the Architectural Transcription Factor HMG-I(Y)

1998 ◽  
Vol 273 (16) ◽  
pp. 9755-9760 ◽  
Author(s):  
Michael T. Chin ◽  
Andrea Pellacani ◽  
Hong Wang ◽  
Sharon S. J. Lin ◽  
Mukesh K. Jain ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Serum Response Factor ◽  
Response Factor ◽  
Serum Response

Human and Drosophila Homeodomain Proteins That Enhance the DNA-Binding Activity of Serum Response Factor

Science ◽  
1992 ◽  
Vol 257 (5073) ◽  
pp. 1089-1095 ◽  
Author(s):  
D. A. Grueneberg ◽  
S. Natesan ◽  
C. Alexandre ◽  
M. Z. Gilman
Keyword(s):  
Dna Binding ◽  
Serum Response Factor ◽  
Binding Activity ◽  
Response Factor ◽  
Homeodomain Proteins ◽  
Dna Binding Activity ◽  
Serum Response

scholarly journals Anticancer Effect of Hypophyllanthin, Niranthin and Lintetralin From Phyllanthus amarus on HeLa Cells And NIH/3T3 Cells

2019 ◽  
Vol 8 (2S7) ◽  
pp. 106-110
Keyword(s):  
Traditional Medicine ◽  
Hela Cells ◽  
Chemical Compounds ◽  
Phyllanthus Amarus ◽  
3T3 Cells ◽  
Anticancer Effect ◽  
Nih 3T3 ◽  
Mtt Assays ◽  
Nih 3T3 Cells

Phyllanthus amarus which is locally known as Dukung Anak was one of the herb used in traditional medicine and research of P. amarus in Malaysia was not widely reported. This present research has isolated three chemical compounds and its anticancer effect of this species has been determined. Three lignans namely hypophyllanthin was afforded from hexane crude while niranthin and lintetralin were afforded from ethanol crude. Anticancer test against HeLa cells and NIH/3T3 cells by MTT assays was tested for its anticancer effect. The result shows that hypophyllanthin was considered to possess an active anticancer effect on HeLa cells than NIH/3T3 cells compared to niranthin and lintetralin.

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