Disentangling the Myc:Max:Mad network (360G-Wellcome-206935_Z_17_Z)

Myc is a transcription factor that is dysregulated and often elevated, in most tumours. However, the proteins reside in an interwoven network of effectors and shared heterodimeric partners which has been suggested to be essential for some, perhaps most of Myc functions. The goal of the project is to investigate this by separating the functions of the Myc:Max heterodimer from the rest of the network, by making use of the fact that both dimerization and specificity of network components is determined by their individual bHLH-Leucine Zipper dimerization domains. Therefore reciprocal specificity variants of Myc and Max based on the heterodimerizing HLHZip domains of the S. cerevisiae RTG1 and RTG3 transcription factors will be used. These domains are different to the mammalian domains so the proteins are unlikely to interfere with other mammalian HLHZip proteins, but likely to still carry out Myc:Max functions. Interactions and functions of MycRTG and MaxRTG in cultured cells, and the ability of the MycRTG/MaxRTG heterodimer to rescue cells lacking wild type Myc will be determined, with assays at the cellular level (e.g. rescue of Myc-dependent cell proliferation) and at the molecular level (ability of MycRTG/MaxRTG to bind E-box containing sequences and regulate Myc/Max transcriptional targets).