title: Repression of Dpp targets in the Drosophila wing by Brinker.
abstract: Patterning along developing body axes is regulated by gradients of transcription factors, which activate or repress different genes above distinct thresholds. Understanding differential threshold responses requires knowledge of how these factors regulate transcription. In the Drosophila wing, expression of genes such as omb and sal along the anteroposterior axis is restricted by lateral-to-medial gradients of the transcriptional repressor Brinker (Brk). omb is less sensitive to repression by Brk than sal and is consequently expressed more laterally. Contrary to previous suggestions, we show that Brk cannot repress simply by competing with activators, but requires specific repression domains along with its DNA-binding domain. Brk possesses at least three repression domains, but these are not equivalent; one, 3R, is sufficient to repress omb but not sal. Thus, although sal and omb show quantitative differences in their response to Brk, there are qualitative differences in the mechanisms that Brk uses to repress them.
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Winter
authors.forename: Gerard
authors.initials: G
authors.lastname: Campbell
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D017344:Genes, Insect / Q000502:physiology*; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014921:Wings, Animal / Q000033:anatomy & histology* / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C118082:brk protein, Drosophila