Feedback control of the EGFR signaling gradient: superposition of domain-splitting events in Drosophila oogenesis.
The morphogenesis of structures with repeated functional units, such as body segments and appendages, depends on multi-domain patterns of cell signaling and gene expression. We demonstrate that during Drosophila oogenesis, the two-domain expression pattern of Broad, a transcription factor essential for the formation of the two respiratory eggshell appendages, is established by a single gradient of EGFR activation that induces both Broad and Pointed, which mediates repression of Broad. Two negative-feedback loops provided by the intracellular inhibitors of EGFR signaling, Kekkon-1 and Sprouty, control the number and position of Broad-expressing cells and in this way influence eggshell morphology. Later in oogenesis, the gradient of EGFR activation is split into two smaller domains in a process that depends on Argos, a secreted antagonist of EGFR signaling. In contrast to the previously proposed model of eggshell patterning, we show that the two-domain pattern of EGFR signaling is not essential for specifying the number of appendages. Thus, the processes that define the two-domain patterns of Broad and EGFR activation are distinct; their actions are separated in time and have different effects on eggshell morphology.
Zartman
Jeremiah J
JJ
Lewis Sigler Institute and Department of Chemical Engineering, Carl Icahn Laboratory, Washington Road, Princeton University, Princeton, NJ 08544, USA.
Kanodia
Jitendra S
JS
Cheung
Lily S
LS
Shvartsman
Stanislav Y
SY
D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000196:embryology* / Q000502:physiology; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D025461:Feedback, Physiological / Q000502:physiology*; D005260:Female; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009866:Oogenesis / Q000502:physiology*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
C102117:Br protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C083884:pnt protein, Drosophila; C110486:sty protein, Drosophila; C075638:aos protein, Drosophila; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; C105053:Kek1 protein, Drosophila; D017027:Protein Tyrosine Phosphatases