Capicua integrates input from two maternal systems in Drosophila terminal patterning.
In Drosophila, the maternal terminal system specifies cell fates at the embryonic poles via the localised stimulation of the Torso receptor tyrosine kinase (RTK). Signalling by the Torso pathway relieves repression mediated by the Capicua and Groucho repressors, allowing the restricted expression of the zygotic terminal gap genes tailless and huckebein. Here we report a novel positive input into tailless and huckebein transcription by maternal posterior group genes, previously implicated in abdomen and pole cell formation. We show that absence of a subset of posterior group genes, or their overactivation, leads to the spatial reduction or expansion of the tailless and huckebein posterior expression domains, respectively. We demonstrate that the terminal and posterior systems converge, and that exclusion of Capicua from the termini of posterior group mutants is ineffective, accounting for reduced terminal gap gene expression in these embryos. We propose that the terminal and posterior systems function coordinately to alleviate transcriptional silencing by Capicua, and that the posterior system fine-tunes Torso RTK signalling output, ensuring precise spatial domains of tailless and huckebein expression.
Cinnamon
Einat
E
Department of Biochemistry, Faculty of Medicine, Hadassah Medical School, The Hebrew University, Jerusalem, Israel.
Gur-Wahnon
Devorah
D
Helman
Aharon
A
St Johnston
Daniel
D
Jiménez
Gerardo
G
Paroush
Ze'ev
Z
D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D024002:HMGB Proteins; D009154:Mutation; D011401:Promoter Regions, Genetic; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D020218:Response Elements; D015398:Signal Transduction / Q000502:physiology; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D024002:HMGB Proteins; C087725:Hkb protein, Drosophila; D012097:Repressor Proteins; C074090:TLL protein, Drosophila; C404284:cic protein, Drosophila; D020794:Receptor Protein-Tyrosine Kinases; C080148:tor protein, Drosophila