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

ABSTRACT: The mechanism of the differential usage of shared binding sites helps drive functional divergence within transcription factor (TF) families. 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. Further, the START domains of PHB and CNA help the TF discriminate if these mutually bound genes are considered “responsive” or “non-responsive” in relation to target regulation. We show that the dSTART domain, too, controls this discrimination of PHB. Taken together, our study shows the dSTART domain employs similar mechanisms of regulation as the START domain, specifically in regulating the differential usage of shared binding sites.

ORGANISM(S): Arabidopsis thaliana

PROVIDER: GSE304240 | GEO | 2026/09/10

REPOSITORIES: GEO