Basic fibroblast growth factor activates serum response factor gene expression by multiple distinct signaling mechanisms. Mol Cell Biol 1999 Jun;19(6):3977-88
Date
05/18/1999Pubmed ID
10330138Pubmed Central ID
PMC104357DOI
10.1128/MCB.19.6.3977Scopus ID
2-s2.0-0033043177 (requires institutional sign-in at Scopus site) 21 CitationsAbstract
Serum response factor (SRF) plays a central role in the transcriptional response of mammalian cells to a variety of extracellular signals. It is a key regulator of many cellular early response genes which are believed to be involved in cell growth and differentiation. The mechanism by which SRF activates transcription in response to mitogenic agents has been extensively studied; however, significantly less is known about regulation of the SRF gene itself. Previously, we identified distinct regulatory elements in the SRF promoter that play a role in activation, including a consensus ETS domain binding site, a consensus overlapping Sp/Egr-1 binding site, and two SRF binding sites. We further showed that serum induces SRF by a mechanism that requires an intact SRF binding site, also termed a CArG box. In the present study we demonstrate that in response to stimulation of cells by a purified growth factor, basic fibroblast growth factor (bFGF), the SRF promoter is upregulated by a complex pathway that involves at least two independent mechanisms: a CArG box-independent mechanism that is mediated by an ETS binding site, and a novel CArG box-dependent mechanism that requires both an Sp factor binding site and the CArG motifs for maximal stimulation. Our analysis indicates that the CArG/Sp element activation mechanism is mediated by distinct signaling pathways. The CArG box-dependent component is targeted by a Rho-mediated pathway, and the Sp binding site-dependent component is targeted by a Ras-mediated pathway. Both SRF and bFGF have been implicated in playing an important role in mediating cardiogenesis during development. The implications of our findings for SRF expression during development are discussed.
Author List
Spencer JA, Major ML, Misra RPAuthor
Ravindra P. Misra PhD Associate Provost, Professor in the Biochemistry department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
3T3 CellsAnimals
Blotting, Northern
DNA-Binding Proteins
Electrophoresis, Polyacrylamide Gel
Fibroblast Growth Factor 2
Gene Expression Regulation
Genes, Reporter
Genes, fos
Genes, ras
Luciferases
Mice
Models, Genetic
Mutagenesis
Nuclear Proteins
Plasmids
Promoter Regions, Genetic
Regulatory Sequences, Nucleic Acid
Rho Factor
Ribonucleases
Serum Response Factor
Signal Transduction
Subcellular Fractions
Time Factors
Transfection
