Transducing the Dpp morphogen gradient in the wing of Drosophila: regulation of Dpp targets by brinker.
Dpp, a TGFbeta, organizes pattern in the Drosophila wing by acting as a graded morphogen, activating different targets above distinct threshold concentrations. Like other TGFbetas, Dpp appears to induce transcription directly via activation of a SMAD, Mad. However, here we demonstrate that Dpp can also control gene expression indirectly by downregulating the expression of the brinker gene, which encodes a putative transcription factor that functions to repress Dpp targets. The medial-to-lateral Dpp gradient along the anterior-posterior axis is complemented by a lateral-to-medial gradient of Brinker, and the presence of these two opposing gradients may function to allow cells to detect small differences in Dpp concentration and respond by activating different target genes.
Campbell
G
G
Department of Genetics and Development, Center for Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA. camp+@pitt.edu
Tomlinson
A
A
D000595:Amino Acid Sequence; D000818:Animals; D052005:Bone Morphogenetic Protein Receptors, Type I; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins; D004742:Enhancer Elements, Genetic / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D017978:Receptors, Growth Factor / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology; D014921:Wings, Animal / Q000254:growth & development
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D017978:Receptors, Growth Factor; C064196:dpp protein, Drosophila; D017346:Protein Serine-Threonine Kinases; D052005:Bone Morphogenetic Protein Receptors, Type I