Sustained induction of egr-1 by v-src correlates with a lack of fos-mediated repression of the egr-1 promoter.
Serum stimulation of quiescent fibroblasts leads to a transient induction of the transcription factor egr-1. However, the induction of egr-1 by v-src was found to be sustained rather than transient. The proto-oncogene fos has been reported to be co-regulated with egr-1 and to repress serum-induced egr-1 expression. We found that c-fos prevents v-src-induced gene expression regulated by the egr-1 promoter. Thus, the sustained induction of egr-1 by v-src could be explained by a lack of c-fos induction by v-src. Consistent with this hypothesis, egr-1 and c-fos were co-induced by serum, but not by v-src, in Balb/c 3T3 cells; v-src did not induce c-fos expression in these cells. We propose that sustained expression of egr-1 induced by v-src in Balb/c 3T3 cells is due to a lack of c-fos down-regulation of egr-1.
Qureshi
S A
SA
Institute for Biomolecular Structure and Function, Hunter College, City University of New York, New York 10021.
Rim
M H
MH
Alexandropoulos
K
K
Berg
K
K
Sukhatme
V P
VP
Foster
D A
DA
D016475:3T3 Cells; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation / Q000502:physiology*; D016762:Genes, fos / Q000502:physiology*; D016391:Genes, src / Q000502:physiology*; D017874:Immediate-Early Proteins; D051379:Mice; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D017874:Immediate-Early Proteins; D014157:Transcription Factors