Honours supervisors and projects

Dr Richard Burke

Molecular genetics of heavy metal homeostasis in Drosophila

Telephone: 9905 9531
Email: richard.burke@sci.monash.edu.au

In the Burke laboratory we study how heavy metal levels are regulated in animals. Metals such as copper, zinc and iron are essential for many vital biological processes but are also potentially toxic at high levels. Strict homeostatic mechanisms are required to maintain correct metal levels. By analysing the function of metal transport proteins and chaperones, we can dissect the molecular pathways required for metal homeostasis and define the biological roles played by these metals.

One key function of copper and zinc is in neuronal function. Copper and zinc transporters are expressed in neuronal tissues, elevated metal levels are observed in the brain, and several key players in human neurodegenerative disease are all known copper binding proteins. We wish to investigate the exact role of metal homeostasis in neurogenesis, in particular in processes such as learning and memory.

Project 1. Characterization of copper and zinc transport pathways

We have isolated a number of known and novel genes required for cellular transport of the essential metals copper and zinc in Drosophila. Mutant phenotypes include defects in pigmentation, eye formation motility, longevity and general growth and development. This project will characterise the function of these genes in metal absorption, development of the fly and neuronal function by generating loss- and gain- of function mutations, testing gene expression patterns, monitoring cellular localization of the gene products and investigating genetic interactions with known metal transport genes.

Project 2. Role of copper in immune function and lymphocyte proliferation

Copper is known to be essential for the formation of melanin which is required for both insect pigmentation and immune system function. Genetically-induced copper deficiency results in loss of adult pigmentation in the fly. Interestingly, suppression of copper homeostasis genes also results in the over proliferation of blood cells in the fly larva and adult, resulting in large melanotic tumours. This project will examine whether this effect on blood cell proliferation is due to direct influence of copper on important growth signalling pathways or an indirect effect of increased oxidative stress in these cells.

Project 3. Modelling amyloidogenic diseases in Drosophila

Several human neurodegenerative diseases feature the accumulation of amyloid plaques linked to disease pathology. The human APP gene is strongly implicated in Alzheimer disease (AD) while the transthyretin (TTR) gene is implicated in many cases of Familial amyloidogenic polyneuropathy (FAP), a rare but fatal hereditary disease causing peripheral neuropathy. This project involves investigation of fly models of these diseases by over expressing wildtype and mutant human APP and TTR in Drosophila neuronal tissues. Such models could aid in the identification of additional genetic factors in AD and FAP and also in drug discovery.

Methods for the above projects will include: generation of transgenic Drosophila strains; immunohistochemistry; generation of Drosophila mutants by imprecise P element excision; tissue sectioning; RNA in situ hybridisation; in vivo monitoring of GFP fusion proteins and reporter genes; RNAi suppression of gene activity; genetic interactions.