A novel cis-regulatory element, the PTS, mediates an anti-insulator activity in the Drosophila embryo.
The Abd-B Hox gene contains an extended 3' cis-regulatory region that is subdivided into a series of separate lab domains. The lab-7 domain activates Abd-B in parasegment 12 (ps12), whereas lab-8 controls expression in ps13. iab-7 is flanked by two insulators, Fab-7 and Fab-8, which are thought to prevent regulatory factors, such as Polycomb silencers, from influencing neighboring iab domains. This organization poses a potential paradox, since insulator DNAs can work in a dominant fashion to block enhancer-promoter interactions over long distances. Here, we present evidence for a novel cis-regulatory sequence located within lab-7, the promoter targeting sequence (PTS), which permits distal enhancers to overcome the blocking effects of Fab-8 and the heterologous su(Hw) insulator. We propose that the PTS converts dominant, long-range insulators into local regulatory elements that separate neighboring lab domains.
Zhou
J
J
Department of Molecular Cell Biology, University of California, Berkeley 94720, USA.
Levine
M
M
D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D004742:Enhancer Elements, Genetic; D005801:Genes, Homeobox / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D017403:In Situ Hybridization; D008957:Models, Genetic; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid
C062393:Abd-B proteins, Drosophila; D029721:Drosophila Proteins; D018398:Homeodomain Proteins