Identification of two novel mouse nuclear proteins that bind selectively to a methylated c-Myc recognizing sequence.
The c-Myc recognizes the sequence CACGTG (Blackwell, T. K., Kretzner, L., Blackwood, E.M., Eisenman, R. N., and Weintraub, H. (1990) Science 250, 1149-1151), and its binding is inhibited by methylation of the core CpG (Prendergast, G. C. and Ziff, E. B. (1991) Science 251, 186-189). We identified two novel nuclear proteins, MMBP-1 and MMBP-2, that bound specifically and under physiological salt condition to the c-Myc binding motif of which cytidine in the CpG sequence was methylated. MMBP-1 was about 42 kD and MMBP-2 was about 63 kD. MMBP-1 was found in specific cells, while MMBP-2 was found in all the cell lines tested, suggesting that MMBP-1 may modulate the role of MMBP-2 in tissue specific manner. We propose that the two proteins play a role in the regulation of c-Myc function through stabilizing or destabilizing the methylation state of the c-Myc binding motif.
Suetake
I
I
Institute for Protein Research, Osaka University, Japan.
Tajima
S
S
Asano
A
A
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002458:Cell Fractionation; D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008297:Male; D008745:Methylation; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016271:Proto-Oncogene Proteins c-myc; D004247:DNA