<i>gt1681</i> mutants are hypersensitive to 6-OHDA.

<p><b>A</b>. The extent of dopaminergic degeneration is indicated for wild-type and <i>gt1681</i> mutant worms after intoxication with 10 mM 6-OHDA. Neurodegeneration of L1 worms was scored after 24, 48 and 72 h as described in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004767#s4" target="_blank">Materials and Methods</a>, and categorized as “complete loss,” “partial loss” or “no loss” phenotypes (labeled black, white and gray, respectively). Asterisks represent statistical significance of differences from wild-type (****p<0.00001). <b>B</b>. Representative images showing progressive stages of dopaminergic neurodegeneration. Absence of degeneration in wild-type (upper left panel) and complete degeneration in <i>gt1681</i> mutant worms 72 h post 6-OHDA intoxication (upper right panel, complete degeneration); lower panel and inset are examples of partial degeneration <i>in gt1881</i>. Arrows indicate ‘blebs in degenerating neurons. <b>C</b>. Extent of neurodegeneration at various developmental stages in wild-type and <i>gt1681</i> mutant worms 72 h post 6-OHDA intoxication. <b>D</b>. In wild-type and <i>gt1681</i> worms, development is equally retarded following treatment with 6-OHDA. Progression to various developmental stages was scored once 95% of untreated worms reached adulthood.