West Coast Worm Meeting Abstracts - Caenorhabditis elegans ...

West Coast Worm Meeting 2000
NEUROTOXIN SENSITIVITY OF DOPAMINERGIC NEURONS
IN C. ELEGANS: ROLE OF THE DOPAMINE TRANSPORTER
AND CELL DEATH PATHWAYS
R. Nass 1,2 , J. Duerr 3 , , J. Rand 3 , D. M. Miller 2,4 , R. D. Blakely 1,2
1Dept of Pharmacol, Vanderbilt U. Med. School, Nashville, TN
2Ctr. for Molecular Neuroscience, Vanderbilt U. Med. School, Nashville, TN
3Program in Molecular and Cell Biology, OMRF, Oklahoma City, OK
4Dept of Cell Biology, Vanderbilt U. Med. School, Nashville, TN
The dopamine transporter (DAT) constitutes the primary mechanism for the inactivation of dopamine (DA)
neurotransmission in the brain. DATs are targets for many psychoactive drugs and the cellular gateway
for the accumulation of the neurotoxin 6-hydroxydopamine (6-OHDA) which evokes neuronal death and
Parkinson-like syndrome in animal models. We have previously cloned and tagged the C. elegans DAT
(CeDAT), and have shown that it is functionally similar to mammalian DATs and expressed exclusively in
the DA neurons (Jayanthi et al. 1998, Nass et al. 1999). We have also developed WT and DAT knockout
transgenic lines which target a CeDAT promotor-GFP fusion to all 8 DA neurons in the hermaphrodite.
Intense GFP expression is seen throughout the axons and dendrites in the live animals. We now show
that a brief exposure to 6-OHDA results in the blebbing of DA neuronal processes, swelling of DA
neuronal cell bodies, and the loss of CeDAT-GFP expression, while co-exposure with CeDAT substrates
or antagonists significantly reduces the 6-OHDA induced response. We also show that this response is
dependent on the expression of CeDAT, since the CeDAT knockout line is insensitive to the effects of the
neurotoxin. Furthermore, the effect appears to be dependent on a necrotic cell death pathway, since the 6
OHDA induced response occurs in a caspase-deficient ced-3 knockout background. These studies as
well as our progress on toxin-based genetic screens for regulators of CeDAT function, localization, and
the toxin mediated cell death will be presented. Supported by MH19732-07 (RN), GM38679 (JR),
NS26115 (DMM), MH58921 (RDB)
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