摘要：

This chapter focuses on the proteins of the Myc network that are essential regulators of cell growth and differentiation. The identification of the Myc partner, Max, in 1991 and the subsequent realization that this protein is the essential dimeric partner for all known c-Myc functions was a major boost to the field and led to a number of very interesting observations and findings. The chapter focuses on c-Myc's role as a transcription factor in the regulation of cell growth, apoptosis, and transformation. The most exciting recent findings suggest that the Myc network not only includes proto-oncoproteins (c-, N-, and L-Myc) but, with the Mad family proteins, also potential tumor suppressors. This together with the fact that Myc proteins as well as Max are essential, as deduced from homozygous disruption of the genes in mice, places the Myc network in a central position in the regulation of cell growth and homeostasis. Genes that have been generated by the duplication of and divergence from an ancestral gene(s) are grouped into families. The myc family of protooncogenes has most likely arisen through such duplications. It currently consists of three well-characterized members; c-myc, N-myc, and L-myc. Two additional genes, B-myc and S-myc, have been identified only in rodents. The c-, N-, and L-myc genes share similar genomic organization and the corresponding proteins contain several regions of high sequence homology. The identification of the Myc dimerization partner Max has significantly advanced our understanding of the molecular function of c-Myc.

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