Regulation of human ornithine decarboxylase expression by the c-Myc.Max protein complex.
The presence of a CACGTG element within a region of the human ornithine decarboxylase (ODC) promoter located at -491 to -474 base pairs 5' to the start site of transcription suggested that the c-Myc.Max protein complex may play a role in the regulation of ODC expression during growth. Electrophoretic mobility shift assays and methylation interference analysis showed that the nuclei of WI-38 cells expressing ODC contained proteins that bound to this region of the ODC gene in a manner that correlated with growth-associated ODC expression. Also, use of antibodies against c-Myc and Max and purified recombinant c-Myc and Max protein in the electrophoretic mobility shift assay confirmed that these proteins can specifically bind this portion of the human ODC promoter. Transient transfection studies showed that increase in the level of c-Myc and/or Max led to a significant enhancement of expression of a human ODC promoter-CAT reporter construct. Moreover, treatment of actively growing WI-38 cells with an antisense oligomer to c-Myc reduced the amount of endogenous protein complex formed and the amount of endogenous ODC mRNA expressed. These studies show that the c-Myc.Max protein complex plays a role in the transcriptional regulation of human ODC in vivo.
Peña
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A
Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
Reddy
C D
CD
Wu
S
S
Hickok
N J
NJ
Reddy
E P
EP
Yumet
G
G
Soprano
D R
DR
Soprano
K J
KJ
D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004247:DNA; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D008969:Molecular Sequence Data; D009955:Ornithine Decarboxylase / Q000235:genetics*; D011401:Promoter Regions, Genetic; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D006133:Growth Substances; C499330:MAX protein, human; C067850:Myc associated factor X; D016271:Proto-Oncogene Proteins c-myc; D011994:Recombinant Proteins; D014157:Transcription Factors; D004247:DNA; D015500:Chloramphenicol O-Acetyltransferase; D009955:Ornithine Decarboxylase