ASK-1 (apoptosis signal-regulating kinase 1) is a direct E2F target gene.
In the present study, we show that E2Fs (E2 promoter-binding factors) regulate the expression of ASK-1 (apoptosis signal-regulating kinase 1), which encodes a mitogen-activated protein kinase kinase kinase, also known as MAP3K5. Its mRNA expression is cell-cycle-regulated in human T98G cells released from serum starvation. Moreover, overexpression and RNA interference experiments support the requirement of endogenous E2F/DP (E2F dimerization partner) activity for ASK-1 expression. Characterization of the human ASK-1 promoter demonstrates that the -95/+11 region is critical for E2F-mediated up-regulation. Chromatin immunoprecipitation assays show that E2F1-E2F4 are bound in vivo to the ASK-1 promoter in cycling cells, probably through a non-consensus E2F-binding site located 12 bp upstream of the transcription start site. Mutation of this site completely abolishes the ASK-1 promoter response to E2Fs as well as the E2F1 binding in electrophoretic mobility-shift experiments. Our results indicate that E2Fs modulate the expression of ASK-1 and suggest that some of the cellular functions of ASK-1 may be under the control of E2F transcription factors. Moreover, the up-regulation of ASK-1 may also favour the p53-independent E2F1 apoptotic activity.
Kherrouche
Zoulika
Z
CNRS UMR 8161, Institut de Biologie de Lille, 1 rue Calmette, BP 447, 59021 Lille, France.
Blais
Alexandre
A
Ferreira
Elisabeth
E
De Launoit
Yvan
Y
Monté
Didier
D
D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D050684:E2F Transcription Factors / Q000502:physiology*; D050687:E2F1 Transcription Factor / Q000502:physiology; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D006801:Humans; D020084:Long Interspersed Nucleotide Elements; D048848:MAP Kinase Kinase Kinase 5 / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000502:physiology; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D050680:Transcription Factor DP1 / Q000502:physiology; D015854:Up-Regulation
D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D050680:Transcription Factor DP1; D048848:MAP Kinase Kinase Kinase 5