The MYC family: three genes, one master switch for growth
T ags: gene families, transcription factors, neuroblastoma, MYCN They switch on growth. They are amplified in tumours. And for decades they were called undruggable. Few gene families are as closely tied to cancer as the MYC family. Its three members, MYC , MYCN and MYCL , encode transcription factors that tell a cell when to grow, divide and build the biomass to do so. When that signal gets stuck on, the consequences are severe. What the MYC proteins do All three share a basic helix-loop-helix leucine zipper (bHLH-LZ) domain. To work, they pair up with a partner protein called MAX, and the MYC–MAX dimer binds E-box sequences (CACGTG) in DNA. From there it regulates a large programme of genes involved in ribosome biogenesis, metabolism, protein synthesis and cell cycle progression. MYC is less a single-target switch than an amplifier of the cell’s existing growth programme. Three siblings, three territories MYC is broadly expressed in proliferating cells and is deregulated in m...