Inhibition of Murine Erythroleukemia Cell Differentiation by Normal and Partially Deleted c-myc Genes

In our study of normal and partially deleted myc genes we found that N- myc, similarly to L- myc, can substitute for c-myc and inhibit MEL cell differentiation. All of the known putative functional domains of c-myc seem to be required for this inhibition. It is conceivable that c-myc inhibits differentiation by a mechanism that is related to its normal role in the cell, possibly by regulating transcription of genes involved in growth promotion. As was previously found for all of the other known activities of c-Myc, the HLH and LZ dimerization motifs are absolutely necessary for inhibition of MEL cell differentiation. Heterodimerization of Myc with Max or Maxclike proteins could be a prerequisite for such inhibition. It is, therefore, of interest to study the regulation of max in MEL cells expressing normal and deregulated myc genes.