Transactivation of the human c-myc gene by c-Myb.
We analyse the contribution of six Myb-binding sites in the upstream c-myc sequences to transactivation by co-transfection assays. Surprisingly, deletion of the six Myb-binding sites did not influence the transactivation of c-myc by c-Myb protein. Instead, the strongest transactivation was observed with a c-myc reporter plasmid which contains only 450 bp of exon 1 including the c-myc promoter P2. An exchange of the DNA binding domain of c-Myb by that of GAL4 led only to small transactivation effects indicating that the DNA binding domain of c-Myb is essential for transactivation of the c-myc gene. These results suggest either an indirect transactivation mechanism of the c-myc gene by c-Myb proteins or a role of the DNA binding domain for additional effects than DNA binding.
Zobel
A
A
Max-Planck-Institut fuer Molekulare Genetik, Abt. Schuster, Germany.
Kalkbrenner
F
F
Vorbrueggen
G
G
Moelling
K
K
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002872:Chromosome Deletion; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D016259:Genes, myc; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D020598:Proto-Oncogene Proteins c-myb; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D015533:Transcriptional Activation; D014162:Transfection
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb