The EGF receptor defines domains of cell cycle progression and survival to regulate cell number in the developing Drosophila eye.
The number of cells in developing organs must be controlled spatially by extracellular signals. Our results show how cell number can be regulated by cell interactions controlling proliferation and survival in local neighborhoods in the case of the Drosophila compound eye. Intercellular signals act during the second mitotic wave, a cell cycle that generates a pool of uncommitted cells used for most ommatidial fates. We find that G1/S progression to start the cell cycle requires EGF receptor inactivity. EGF receptor activation is then required for progression from G2 to M phase of the same cells, and also prevents apoptosis. EGF receptor activation depends on short-range signals from five-cell preclusters of photoreceptor neurons not participating in the second mitotic wave. Through proliferation and survival control, such signals couple the total number of uncommitted cells being generated to the neural patterning of the retina.
Baker
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Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA. baker@aecom.yu.edu
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D000818:Animals; D002452:Cell Count; D018797:Cell Cycle Proteins; D002470:Cell Survival / Q000502:physiology; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism*; D005123:Eye / Q000166:cytology / Q000196:embryology; D016193:G1 Phase / Q000502:physiology; D016195:G2 Phase / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008938:Mitosis / Q000502:physiology*; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases; D020687:cdc25 Phosphatases / Q000235:genetics / Q000378:metabolism
D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D008565:Membrane Proteins; C076026:spi protein, Drosophila; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D010749:Phosphoprotein Phosphatases; D017027:Protein Tyrosine Phosphatases; D020687:cdc25 Phosphatases; C059217:stg protein, Drosophila