DOMAINS OF HUMAN C-MYC PROTEIN REQUIRED FOR AUTOSUPPRESSION AND COOPERATION WITH RAS ONCOGENES ARE OVERLAPPING

Amino acids 106 to 143 and 354 to 433 of the human c-myc protein (439 amino acids) were shown to be required for the protein to suppress c-myc gene transcription and were found to exactly overlap with those necessary for c-myc to cooperate with ras oncogenes in the transformation of rat embryo fibroblasts. The essential carboxyl-terminal region harbors structural motifs (a basic region, a helix-loop-helix motif, and a "leucine zipper") which, in other proteins, can mediate dimerization and sequence-specific DNA binding.