v-Fps-responsiveness in the Egr-1 promoter is mediated by serum response elements.

AUTOR(ES)

Alexandropoulos, K

RESUMO

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.

Documentos Relacionados

• A ternary complex factor-dependent mechanism mediates induction of egr-1 through selective serum response elements following antigen receptor cross-linking in B lymphocytes.
• Intramolecular recombination in polyomavirus DNA is controlled by promoter elements.
• 12-O-tetradecanoylphorbol-13-acetate activation of the MDR1 promoter is mediated by EGR1.
• Ionizing radiation activates transcription of the EGR1 gene via CArG elements.
• Krüppel-associated box-mediated repression of RNA polymerase II promoters is influenced by the arrangement of basal promoter elements.