A cryptic START domain regulates deeply conserved transcription factors [ChIP-Seq]

In the CLASS III HOMEODOMAIN LECUINE ZIPPER (HD-ZIPIII) family of TFs, the divergence between CORONA (CNA) and PHABULOSA (PHB) paralogs is in part regulated by their START domains. Here we test if the newly identified disorder-containing START (dSTART) domain is also involved in regulating the mechanism of divergence.

We show that the genes bound between PHB and PHB-d∆ have near complete overlap (~98%). However, at the shared sites, ChIP signal intensities were either higher in PHB peaks or equally strong between PHB and PHB-d∆. This suggests that, like the START domains of CNA and PHB, the dSTART domain is important for DNA binding affinity at specific sites in the genome.