Title

An accelerated assay for the identification of life span extending interventions in Drosophila melanogaster

Date of Completion

January 2005

Keywords

Biology, Genetics

Degree

Ph.D.

Abstract

Recent advances in aging research have uncovered genes and genetic pathways that influence life span in such diverse organisms as yeast, nematodes, flies and mice. Continued discovery of new genes and therapeutic drugs that affect the aging process has been confounded by the absence of a phenotype other than death of the organism. Until now, time-consuming life span analysis remained the only method available for detecting interventions affecting life span. The necessity of performing such life spans for each genetic or pharmacological intervention makes the logistics and feasibility of conducting large drug screens or mutagenesis experiments quite daunting. ^ Reported here is the development of a rapid assay in D. melanogaster that utilizes the expression of molecular biomarkers of aging as a surrogate indicator of physiological age. When a toxin reporter gene is expressed under the control of a biomarker of aging driver, it leads to early death of the fly and reduction of life span by ∼80%. This greatly reduces the time needed to perform analysis. At the same time, biomarker driven toxin expression is age dependent and can be used to identify interventions resulting in life span change. This assay recapitulates the effects of known life span extending interventions, such as ambient temperature, dietary restriction and reproductive status. Furthermore, single gene mutations that have been shown to extend life span can be identified using this system. This assay can be used as a high-throughput screen for testing the effects of drugs on life span and provides the basis for a mutagenesis with the goal of isolating single gene mutations that extend life span. ^ Also reported here is a unique linamarin/linamarase system for use as an inducible cyanide expression system in Drosophila. UAS-Linamarase lines can be used in conjunction with any GAL4 based driver and will produce cyanide in the presence of linamarin. This system could provide the inducibility needed to produce a more refined screening system using age-dependent drivers, similar to the non-inducible rapid assay previously described. The linamarin/linamarase system may also prove useful as a driver specific inducible toxin tool for use in tissue specific ablation studies. ^