Cell type-specific trans-activation by the B-myb gene product: requirement of the putative cofactor binding to the C-terminal conserved domain.
The myb gene family has three members, c-myb, A-myb and B-myb. We have examined the trans-activating capacity of the B-myb gene product (B-Myb) in various types of cells. B-Myb functions as a transcriptional activator in CV-1 and HeLa cells, but not in NIH3T3 cells, indicating that B-Myb is a cell type-specific transcriptional activator. Deletion analyses of B-Myb have demonstrated that the region conserved between three members of the myb gene family (CR for conserved region) is necessary for trans-activation by B-Myb. An in vivo competition assay suggests that regulatory factor(s) that binds to the CR of B-Myb is required for transactivation. Analyses using an affinity resin show that multiple proteins bind to the CR of B-Myb and that the CR-binding proteins in CV-1 and HeLa cells are different from those in NIH3T3 cells. These results suggest that the CR-binding cofactor(s) is critical for the cell type-specific trans-activation by B-Myb.
Tashiro
S
S
Laboratory of Molecular Genetics, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan.
Takemoto
Y
Y
Handa
H
H
Ishii
S
S
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002522:Chlorocebus aethiops; D016384:Consensus Sequence; D017931:DNA Primers / Q000737:chemistry; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009857:Oncogenes; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators
D017931:DNA Primers; D015534:Trans-Activators