Figure 4. Suppression of the high LRO Nile red phenotype of
kat-1 by mutations in the proton coupled amino acid transmembrane transporter
skat-1. (A) a
kat-1 mutant has a doubling of LRO Nile red. A
skat-1 single mutant has a 30% reduction in LRO Nile red. The
kat-1;
skat-1 double mutant show a near complete absence of LRO Nile red, indicating that
skat-1 completely suppresses the high LRO Nile red of a
kat-1 mutant. Representative images of individual animals are shown in the right panel. (B) As with the
kat-1;
skat-1 double mutant, loss of
skat-1 in mutants lacking serotonin (
tph-1 and
cat-4) show a synergistic decrease in LRO Nile red. The dramatic increase in LRO Nile red in the
kat-1;
tub-1 double mutant is strongly suppressed in the
kat-1;
skat-1;
tub-1 triple mutant (representative image shown at right). (A and B, N.25, significance by ANOVA with Bonferroni correction.) (C)
skat-1 acts in the intestine in a cell autonomous manner to regulate LRO Nile red. Expression of
skat-1 under the intestine specific promoter
vha-6 in a
kat-1;
skat-1 double mutant fully restores the high LRO Nile red phenotype of a
kat-1 mutant, whereas expression in the nervous system under the
rab-3 promoter does not. (D) SKAT-1::GFP expressed under the intestine-specific
vha-6 promoter highlights hollow vesicles which are also positive for autofluorescent material, likely representing lysosome-related organelles (arrows). A large amount of SKAT-1::GFP is localized to smaller, more punctate cytoplasmic structures and does not co-localize with autofluorescent material (angle brackets).