The enhancer of rudimentary gene, e(r), encodes a transcription co-activator that has been shown to activate the Notch gene, N, signaling pathway and the pyrimidine biosynthetic pathway. The interaction with Notch has been identified through a lethal interaction between null alleles of e(r) and viable hypomorphic alleles of Notch with a mutation of deltex. We hypothesize that loss of e(r) activity results in a reduction in Notch expression which results in lethality. The stage at which the lethality occurs should indicate the stage at which Notch activation by e(r) is crucial. Both the N and e(r) genes are on the X chromosome, so lethal interactions can be seen as the absence of hemizygous males, however, the flies can only be scored as adults. In order to access the presence of N and e(r) mutant larvae, we utilized a wild-type X chromosome carrying the GFP gene. In the lethality crosses, heterozygous female larvae and wild-type male larvae will GFP+, while N e(r) mutant larvae will be GFP-. Using this approach, we determined that N e(r) mutant flies are fully viable as larvae, but they dies during the pupal stage. These data suggest that e(r) is activating N during the pupal stage, and that this activation is necessary for the normal development of the fly during metamorphosis.
|Presenters:||Hannah Cushman (Graduate Student)
Stuart Tsubota (Faculty)
|Time:||10:45 am (Session II)|