Our long-term objective is to understand how genes control the specialization of body segments in Drosophila. Much of our work is focused on the homeotic gene spineless (ss), which specifies the identity of the distal antenna, ss encodes a bHLH PAS transcription factor that is the closest known homolog of the mammalian aryl hydrocarbon receptor (Ahr). Our major objectives are to determine how antennal expression of ss is regulated and how ss controls its downstream targets. Interactions of the upstream regulators Dll, Hth, and Exd with a 521 bp antennal enhancer from ss will be characterized in detail. Interactions between Ss, Hth, Dll, and Exd with three enhancers likely controlled by Ss will also be characterized. Two likely Ss targets identified encode antenna-specific detoxification genes; if these prove to be direct targets of Ss, we will test whether Ahr controls expression of similar genes known to be expressed in the mammalian olfactory system. Our second major focus is on how adult abdominal segments are patterned. We have shown that mutations in the ecdysone-inducible gene E93 cause defects in numerous patterning events in the early pupa, including the patterning of the abdominal tergites. In normal development, many target genes appear to change their responses to EGFR, Hh, and Dpp signaling in the early pupal period; E93 may be at least partly responsible for directing this transition. Our specific goals are to identify products of E93 that function in imaginal patterning, determine the extent to which the early pupal transition is affected by E93, and identify targets of E93 involved in patterning. We also plan to characterize three novel genes that regulate pigmentation in the abdomen; these genes will be mapped and their relationships determined to omb and bob, key pigmentation regulators identified in previous work. Our work will provide insights into the functioning of Ahr, and may lead to a better understanding of how target gene specificity is controlled for signaling systems known to play an important role in cancer.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Development - 1 Study Section (DEV)
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Haynes, Susan R
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Washington University
Schools of Arts and Sciences
Saint Louis
United States
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Mou, Xiaochun; Duncan, Dianne M; Baehrecke, Eric H et al. (2012) Control of target gene specificity during metamorphosis by the steroid response gene E93. Proc Natl Acad Sci U S A 109:2949-54
Duncan, Dianne; Kiefel, Paula; Duncan, Ian (2010) Control of the spineless antennal enhancer: direct repression of antennal target genes by Antennapedia. Dev Biol 347:82-91
Emmons, Richard B; Duncan, Dianne; Duncan, Ian (2007) Regulation of the Drosophila distal antennal determinant spineless. Dev Biol 302:412-26
Kankel, Mark W; Duncan, Dianne M; Duncan, Ian (2004) A screen for genes that interact with the Drosophila pair-rule segmentation gene fushi tarazu. Genetics 168:161-80
Kopp, Artyom; Duncan, Ian (2002) Anteroposterior patterning in adult abdominal segments of Drosophila. Dev Biol 242:15-30
Kopp, A; Blackman, R K; Duncan, I (1999) Wingless, decapentaplegic and EGF receptor signaling pathways interact to specify dorso-ventral pattern in the adult abdomen of Drosophila. Development 126:3495-507
Emmons, R B; Duncan, D; Estes, P A et al. (1999) The spineless-aristapedia and tango bHLH-PAS proteins interact to control antennal and tarsal development in Drosophila. Development 126:3937-45
Kopp, A; Muskavitch, M A; Duncan, I (1997) The roles of hedgehog and engrailed in patterning adult abdominal segments of Drosophila. Development 124:3703-14
Kopp, A; Duncan, I (1997) Control of cell fate and polarity in the adult abdominal segments of Drosophila by optomotor-blind. Development 124:3715-26
Breen, T R; Duncan, I M (1986) Maternal expression of genes that regulate the bithorax complex of Drosophila melanogaster. Dev Biol 118:442-56

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