tramtrack acts downstream of numb to specify distinct daughter cell fates during asymmetric cell divisions in the Drosophila PNS.
Asymmetric cell divisions allow a sensory organ precursor (SOP) cell to generate a neuron and its support cells in the Drosophila PNS. We demonstrate a role of tramtrack (ttk), previously identified as a zinc finger-containing putative transcription factor, in the determination of different daughter cell fates. Both loss of function and overexpression of ttk affect the fates of the SOP progeny. Whereas loss of ttk function transforms support cells to neurons, ttk overexpression results in the reverse transformation. ttk is expressed in support cells but not in neurons. It has been shown that numb, a membrane-associated protein asymmetrically distributed during the SOP division, confers different daughter cell fates. Loss of ttk or numb function results in reciprocal cell fate transformation. Epistatic studies suggest that ttk acts downstream of numb. We propose that ttk executes the command dictated by asymmetrically localized numb to specify distinct daughter cell fates during multiple asymmetric divisions.
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Howard Hughes Medical Institute, Department of Physiology, University of California at San Francisco 94143, USA.
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D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D015870:Gene Expression; D007605:Juvenile Hormones / Q000235:genetics / Q000502:physiology*; D017933:Peripheral Nervous System / Q000166:cytology* / Q000196:embryology / Q000254:growth & development; D012097:Repressor Proteins; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D007605:Juvenile Hormones; D012097:Repressor Proteins; C060606:numb protein, Drosophila; C075878:ttk protein, Drosophila