FIG. 1.

Functional domains of Myc. The amino-terminal domain (NTD) of Myc contains two conserved sequences, Myc Box 1 (MBI) and Myc Box II (MBII), that are required for transcriptional activation activity. The carboxyl-terminal domain (CTD) contains the b/HLH/Z domain, which is responsible for dimerization with Max and binding to E-box DNA. A nuclear localization signal (NLS) is present in the central region of the protein. The arrowheads point to multiple phosphorylation sites reported previously. The Myc fragments used in the following experiments are peptide 1 to 352 (NT-Myc) and peptide 353 to 439 (CT-Myc).