Department of Zoology, University of Hawai`i 2538 McCarthy Mall, Edmondson 152 Honolulu, HI 96822 phone: (808) 956-8088 fax: (808) 956-9812 robinow@hawaii.edu
One project in the lab focuses on the regulation of programmed cell death, or apoptosis, in the nervous system. In Drosophila, the genes reaper, grim and head involution defective (hid) induce apoptosis when expressed at high levels. We have identified two distinct sets of neurons that die by apoptosis shortly after the emergence of the adult from the pupal case at the conclusion of metamorphosis, in a low steroid hormone environment. Both sets of neurons accumulate reaper and grim transcripts, but not hid transcripts immediately prior to their death. Application of the biologically active steroid 20-hydroxyecdysone prevents transcription of these genes and prevents the death of these neurons. We have identified a genomic region that regulates expression of the grim gene that is sensitive to the titer of 20E. We are currently characterizing this region to determine the mechanism by which 20E represses transcription of this gene.
The steroid hormone 20E drives Drosophila development by interacting with nuclear receptors that act as ligand regulated transcription factors. To define the cellular mechanisms and interactions involved in nuclear receptor signaling, we are currently conducting a screen to identify genes that are involved in nuclear receptor signaling pathways. This screen is designed to identify genes that function during metamorphosis when the animal undergoes a dramatic reorganization. Characterization of genes identified in this screen will help define the molecular pathways that are regulated by hormones during development.
Sung C, Robinow S. 2000. Characterization of the regulatory elements controlling neuronal expression of the A-isoform of the ecdysone receptor gene of Drosophila melanogaster. Mechanisms of Development 91:237-248.
Draizen TA, Ewer J, Robinow S. 1999. Genetic and hormonal regulation of the death of peptidergic neurons in the Drosophila CNS. J Neurobiol 38:455-465.
Robinow S, Draizen TA, Truman JW. 1997. Genes that induce apoptosis: transcriptional regulation in identified, doomed neurons of the Drosophila CNS. Devel Biol 190:206-213.