In vertebrates, large exons often skip splicing events and are evolutionarily conserved. Scientists from Nagoya University, Japan, led by Associate Professor Akio Masuda, have recently identified the mechanism behind regulated splicing of large constitutive exons which are rich in disordered regions, and their potential involvement in the assembly of transcription factors. They also explained how dual-regulation by two distinct groups of splicing factors ensures phase-separation of large exon-containing transcription factors.