Epithelial-mesenchymal transition (EMT) is a cell state change used repeatedly during development across evolution, while aberrant EMT is associated with cancer metastasis. The transcriptional control of EMT has been extensively studied, and several transcription factors (TFs) shown to play crucial roles; notably, TFs such as Twist and Snail have been proposed to be ‘master regulators’ of EMT. On , Lindsay Saunders and David McClay challenge this concept by analysing the specific functions of TFs implicated in the EMT gene regulatory network (GRN) of early sea urchin embryos. The authors analyse five features of EMT - basement membrane remodelling, de-adhesion, apical constriction, loss of apico-basal polarity and directed motility - and find that different TFs show varying effects on each of these processes. They then use these data to build sub-circuits within the GRN for each feature. Strikingly, none of the TFs are involved in all five sub-circuits, implying that - in sea urchin at least - the idea of a master regulator for EMT does not hold.
