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Poster Full Abstracts - Drosophila Models of Human Diseases
Poster board number is above title. The first author is the presenter
246
Hsp70 activity was diminished suggesting TPI[sgk] is a functional protein and that reducing TPI[sgk] degradation can abrogate disease pathogenesis. The
autophagy pathway was also assessed for a role in TPI[sgk] degradation and no change in TPI[sgk] degradation was observed with pharmacological studies.
423C
Neurodegeneration in a Temporally-Controlled Fly Model of Huntington’s Disease.
Kurt Jensen
1
, Diego Rincon-Limas
1
, Pedro Fernandez-Funez
1,2
. 1)
Neurology, University of Florida, Gainesville, FL; 2) Neurosciences, University of Florida, Gainesville, FL.
Huntington’s disease (HD) is a devastating condition characterized by accumulation of Huntingtin-containing intranuclear inclusions in the brain neurons
of affected individuals. Unfortunately, the exact mechanism by which the expanded Huntingtin protein (Htt) leads to neurotoxicity is not clear. HD is a
complex disease, and early changes that lead to neuropathology are not obvious. These early changes are particularly difficult to detect in
Drosophila
since
traditional UAS-controlled transgenes result in gene expression in developing neurons, potentially causing both neurodevelopmental and neurodegenerative
phenotypes. We opted to overcome this drawback by inducing ubiquitous expression of mutant Htt under the temporal control of the Gal80
ts
repressor. In our
system, Gal80
ts
; da>Gal4 flies were mated to UAS-Htt flies, and the resulting progeny were kept at 18°C throughout development (Gal80 active, system off).
Upon eclosion, the adult flies were shifted to 31.5°C (Gal80 inactive, system on) and aged for up to 20 days. First, we determined the “on” kinetics of mutant
Htt at both the RNA and protein levels. Muatnt
Htt
RNA was detected soon after induction, and mutant Htt protein was detected shortly thereafter. Then, we
characterized this HD fly model functionally, histologically, and biochemically over time. The mutant Htt protein formed high-molecular weight aggregates,
and changes in other HD-related pathology markers were also observed. Minor ultrastructural changes in brain structure were observed in the
photoreceptors; however, these flies demonstrated a pronounced lethality. These results demonstrate the utility of establishing a model for HD that more
rigorously controls transgene expression, while still providing a relevant disease model. We hope that this system will be exploited to further dissect HD and
other neurodegenerative disease pathways.
424A
A Drosophila model of Multisystem proteinopathy caused by VCP/p97 mutation.
Nam Chul Kim, J. Paul Taylor. Developmental Neurobiology, St.Jude
Children's Research Hospital, Memphis, TN.
Multisystem proteinopathy (MSP) caused by mutations in valosin-containing protein (VCP)/p97, formerly known as IBMPFD-ALS, is an adult onset
progressive disease affecting muscles (inclusion body myopathy), bone (Paget’s disease of bone), the brain (frontotemporal dementia) and motor neurons
(amyotrophic lateral sclerosis). As a recent study indentified VCP/p97 mutations in sporadic and familial forms of ALS, we generated and characterized a
Drosophila model of ALS caused by VCP mutation to elucidate the role of VCP in disease pathogenesis. In 3rd instar larvae, mutant model animals have
developmental defects in their neuromuscular junction (NMJ) such as small and premature synapses and a reduction in active zones . In adult abdominal
NMJs, we found unstable and denervated synapses called footprints. Motor neuron dendrite formation was also significantly reduced in 3rd instar larval
stage. Electron microscopy study revealed that motoneuron axons in mutant animals were severely degenerated. In NMJs and axons, fewer mitochondrias
were observed compared to wild type control and the velocity of their transport also decreased. These defects by overexpression of dVCP
R152H
mutant protein
in motor neurons resulted in abnormal locomotor behavior in 3rd instar larval stage (crawling) and also in adult stage (walking and flying). Therefore, this
Drosophila model successfully recapitulates several important disease phenotypes of ALS patients and will be beneficial for further characterization of the
disease mechanism in motor neurons.
425B
Accumulation of insoluble forms of FUS protein correlates with toxicity in drosophila.
Magalie Lecourtois, Laetitia Miguel, Tracey Avequin, Morgane
Delarue, Sébastien Feuillette, Thierry Frébourg, Dominique Campion. UMR Inserm U614, IFRMP23, Rouen Institute for Medical Research and Innovation,
Faculty of Medicine, University of Rouen, 22 Boulevard Gambetta, 76183 Rouen Cedex 01, France.
The Fused in Sarcoma/translated in liposarcoma (FUS) protein is highly conserved and ubiquitously expressed. Physiologically, FUS is primarily located
in the nucleus, but continuously shuttles between nucleus and cytoplasm. The precise roles of the protein are not fully elucidated, although FUS is known to
be involved in multiple levels of RNA processing including transcription, pre-mRNA splicing, transport to and rapid local RNA translation at the synapse,
and decay. Last, FUS proteins may also be involved in microRNA biogenesis. Recently, FUS has been identified as a major constituent of nuclear and/or
cytoplasmic ubiquitin-positive inclusions in patients with frontotemporal lobar degeneration (FTLD) or amyotrophic lateral sclerosis (ALS). In brain tissue
of patients presenting FTLD with FUS pathology, pathological FUS proteins shift towards an insoluble fraction. To explore aspects of FUS pathogenesis in
vivo, we have developed a new Drosophila transgenic model expressing a wild-type isoform of human FUS protein. We found that when expressed in retinal
cells, FUS proteins are mainly recovered as soluble forms and their overexpression results in a mild eye phenotype, with malformed interommatidial bristles
and the appearance of ectopic extensions. On the other hand, when FUS proteins are specifically targeted to adult differentiated neurons, they are mainly
recovered as insoluble forms, and their overexpression drastically reduces fly lifespan. Importantly, FUS neurotoxicity occurs regardless of inclusion
formation. Lastly, we showed that molecular chaperones reduce FUS toxicity by modulating protein solubility. Altogether, our data indicate that
accumulation of insoluble non-aggregated FUS forms might represent the primary toxic species in human FUS proteinopathies.
426C
Use of
Drosophila
cultured cells to investigate homeostasis and toxicity of metals such as copper, manganese and zinc.
Stephanie E. Mohr
1
, Quentin
Gilly
1
, Benjamin McElvany
1
, Claire Y. Hu
1
, Ian T. Flockhart
1
, Donghui Yang-Zhou
1
, Norbert Perrimon
1,2
. 1) Dept Gen, Harvard Med Sch, Boston, MA; 2)
HHMI, Harvard Med Sch, Boston, MA.
Metals such as copper, manganese and zinc are essential to cell survival but in excess, the same metals can result in cell death and disease. Thus,
maintaining appropriate intracellular metal levels is critically important to cell survival. We have developed a platform for studying metal homeostasis and
toxicity using
Drosophila
cultured cells. As expected, low levels of metal supplementation have beneficial or neutral effects on cell viability as measured by
a total cellular ATP readout, whereas supplementation with high levels significantly reduces cell viability. To test the utility of RNAi screening as a method
for identifying factors required for metal homeostasis and toxicity, we generated RNAi reagents for knockdown of 50 gene candidates identified based on
similarity to genes conferring sensitivity or resistance to metal supplementation in other model systems. As expected, several membrane transporters and