v-Fps-responsiveness in the Egr-1 promoter is mediated by serum response elements.
Egr-1, a mitogen-responsive transcription factor, is rapidly induced by v-Fps in the absence of protein synthesis. Thus, Egr-1 is a primary response to the protein-tyrosine kinase activity of v-Fps. To determine the v-Fps-responsive elements in the Egr-1 promoter, deletion mutants of the Egr-1 promoter were used in transient expression assays. A v-Fps expression vector was contransfected into NIH 3T3 cells with chloramphenicol acetyl transferase (CAT) gene expression vectors under the control of the Egr-1 promoter or the Egr-1 promoter containing various deletions. Responsiveness to v-Fps was restricted to a region that contained repeated CC(A/T)6GG sequences, known as CArG boxes. CArG boxes form the core of serum response element (SREs). v-Fps-induced Egr-1 promoter activation was lost by sequential removal of four tandemly repeated SREs. This region, containing four SREs, was found to be sufficient for maximal Egr-1 induction by v-Fps when placed upstream from a heterologous promoter. Individual SREs from this region were able to respond to v-Fps, however, the activation of the individual SREs was lower than that observed for the clustered SREs. These data suggest that v-Fps-responsiveness in the Egr-1 promoter is mediated by SREs.
Alexandropoulos
K
K
Institute for Biomolecular Structure and Function, Hunter College, City University of New York, NY 10021.
Qureshi
S A
SA
Rim
M
M
Sukhatme
V P
VP
Foster
D A
DA
D016475:3T3 Cells; D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D015681:Fusion Proteins, gag-onc / Q000378:metabolism*; D005786:Gene Expression Regulation; D017874:Immediate-Early Proteins; D051379:Mice; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats; D026362:Serum Response Factor; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; C486110:Egr1 protein, rat; D015681:Fusion Proteins, gag-onc; D017874:Immediate-Early Proteins; D009687:Nuclear Proteins; D026362:Serum Response Factor; D014157:Transcription Factors; D011505:Protein-Tyrosine Kinases; C068415:v-fps oncogene protein, Fujinami sarcoma virus