Mechanism of c-Myb-C/EBP beta cooperation from separated sites on a promoter.
c-Myb, but not avian myeloblastosis virus (AMV) v-Myb, cooperates with C/EBP beta to regulate transcription of myeloid-specific genes. To assess the structural basis for that difference, we determined the crystal structures of complexes comprised of the c-Myb or AMV v-Myb DNA-binding domain (DBD), the C/EBP beta DBD, and a promoter DNA fragment. Within the c-Myb complex, a DNA-bound C/EBP beta interacts with R2 of c-Myb bound to a different DNA fragment; point mutations in v-Myb R2 eliminate such interaction within the v-Myb complex. GST pull-down assays, luciferase trans-activation assays, and atomic force microscopy confirmed that the interaction of c-Myb and C/EBP beta observed in crystal mimics their long range interaction on the promoter, which is accompanied by intervening DNA looping.
Tahirov
Tahir H
TH
Kanagawa Academy of Science and Technology, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan. tahir@med.yokohama-cu.ac.jp
Sato
Ko
K
Ichikawa-Iwata
Emi
E
Sasaki
Motoko
M
Inoue-Bungo
Taiko
T
Shiina
Masaaki
M
Kimura
Kazumi
K
Takata
Shioka
S
Fujikawa
Atsushi
A
Morii
Hisayuki
H
Kumasaka
Takashi
T
Yamamoto
Masaki
M
Ishii
Shunsuke
S
Ogata
Kazuhiro
K
D000123:Acetyltransferases; D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003461:Crystallography; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000502:physiology; D009690:Nucleic Acid Conformation; D020626:Oncogene Proteins v-myb / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000502:physiology*; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D013329:Structure-Activity Relationship; D015533:Transcriptional Activation / Q000502:physiology
D022782:CCAAT-Enhancer-Binding Protein-beta; D020626:Oncogene Proteins v-myb; D011506:Proteins; D016271:Proto-Oncogene Proteins c-myc; D000123:Acetyltransferases; C077509:mim-1 protein, Gallus gallus