RT Journal Article SR Electronic T1 Caudal counter-represses Hunchback to regulate even-skipped stripe 2 expression in Drosophila embryos JF bioRxiv FD Cold Spring Harbor Laboratory SP 226373 DO 10.1101/226373 A1 Ben J. Vincent A1 Max V. Staller A1 Francheska Lopez-Rivera A1 Meghan D.J. Bragdon A1 Zeba Wunderlich A1 Javier Estrada A1 Angela H. DePace YR 2017 UL http://biorxiv.org/content/early/2017/11/28/226373.abstract AB Hunchback is a bifunctional transcription factor that can activate and repress gene expression in Drosophila development. We investigated the regulatory DNA sequence features that control Hunchback function by perturbing enhancers for one of its target genes, even-skipped. While Hunchback directly represses the eve stripe 3+7 enhancer, we found that in the eve stripe 2+7 enhancer, Hunchback repression is prevented by Caudal binding—this relationship is called counter-repression. We found evidence that this relationship is conserved by comparing predicted binding sites for Hunchback and Caudal across orthologous eve stripe 2 enhancers. These results alter the textbook view of eve stripe 2 regulation wherein Hb is depicted as a direct activator. Instead, to generate stripe 2, Hunchback repression must be counteracted by Caudal binding. We discuss the implications of this interaction for eve stripe 2 regulation and evolution.