Fig 6. Dendrite overgrowth may reflect expansion of a sensory compartment. (A, B)
mapk-15 mutants expressing the oxygen-sensing guanylate cyclase GCY35-HA-GFP and soluble mCherry under control of a URX-specific promoter (
gcy-37pro)were imaged (A) at the L3 stage before overgrowth or (B) at the L4 stage afterovergrowth. (C) Wild-type,
mapk-15,
mapk-15;
tax-2,
egl-4(gf),and
mapk-15;
egl-4(gf)animals were synchronized as two-day adults and dendrite and nose lengths weremeasured.
mapk-15 and
mapk-15;
tax-2 mutants carried transgenes overexpressing wild-type GCY-35 or a cyclase-dead mutant (GCY-35D473A). Colored bars,individual dendrites; black bars, population averages. Brackets indicate numbers of dendrites in the indicated range. (D) URX calcium responses to a 7%-21% oxygenshift were measured in wild-type (n = 18),
mapk-15 animals with dendrite overgrowth (n = 17), and
gcy-35 animals (n = 10) as sensory-defective controls. Solid lines,average YFP/CFP ratio; shaded areas, SEM; black bars, time intervals used for statistical comparison vs wild-type control. n = 15 in all cases. (E) Locomotory activity wasmeasured in response to 7%-14%-17%-21% oxygen shifts for
npr-1 animals,
npr-1;
mapk-15 animals with or without URX overgrowth, and
npr-1;
gcy-35;
gcy-36animals as sensory-defective controls. Solid lines, average speed; shaded areas, SEM; black bars indicate time intervals used for statistical comparisons. Color-coded pvalues,
mapk-15 with/without overgrowth vs
npr-1 controls (n > 70). Comparison of
mapk-15 animals with overgrowth vs those without overgrowth yielded p>0.05 forall conditions. In all panels, p-values were calculated with the Mann-Whitney U test.