An RFX transcription factor regulates ciliogenesis in the closest living relatives of animals

Cilia allowed our protistan ancestors to sense and explore their environment, avoid predation, and capture bacterial prey.¹^(,)²^(,)³ Regulated ciliogenesis was likely critical for early animal evolution,²^(,)⁴^(,)⁵^(,)⁶ and in modern animals, deploying cilia in the right cells at the right time is crucial for development and physiology. Two transcription factors, RFX and FoxJ1, coordinate ciliogenesis in animals⁷^(,)⁸^(,)⁹ but are absent from the genomes of many other ciliated eukaryotes,...