title: Huckebein repressor activity in Drosophila terminal patterning is mediated by Groucho.
abstract: The Groucho corepressor mediates negative transcriptional regulation in association with various DNA-binding proteins in diverse developmental contexts. We have previously implicated Groucho in Drosophila embryonic terminal patterning, showing that it is required to confine tailless and huckebein terminal gap gene expression to the pole regions of the embryo. Here we reveal an additional requirement for Groucho in this developmental process by establishing that Groucho mediates repressor activity of the Huckebein protein. Putative Huckebein target genes are derepressed in embryos lacking maternal groucho activity and biochemical experiments demonstrate that Huckebein physically interacts with Groucho. Using an in vivo repression assay, we identify a functional repressor domain in Huckebein that contains an FRPW tetrapeptide, similar to the WRPW Groucho-recruitment domain found in Hairy-related repressor proteins. Mutations in Huckebein's FRPW motif abolish Groucho binding and in vivo repression activity, indicating that binding of Groucho through the FRPW motif is required for the repressor function of Huckebein. Taken together with our earlier results, these findings show that Groucho-repression regulates sequential aspects of terminal patterning in Drosophila.
authors.affiliation: Department of Biochemistry, Hadassah Medical School, The Hebrew University, PO Box 12272, Jerusalem 91120, Israel.
authors.forename: R E
authors.initials: RE
authors.lastname: Goldstein
authors.forename: G
authors.initials: G
authors.lastname: Jiménez
authors.forename: O
authors.initials: O
authors.lastname: Cook
authors.forename: D
authors.initials: D
authors.lastname: Gur
authors.forename: Z
authors.initials: Z
authors.lastname: Paroush
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D019521:Body Patterning / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics*; D029721:Drosophila Proteins; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000235:genetics*; D008297:Male; D008954:Models, Biological; D009154:Mutation; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics*; D020798:Two-Hybrid System Techniques
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D012097:Repressor Proteins; C087725:Hkb protein, Drosophila; C091023:gro protein, Drosophila