Pan-neuronal, pioneer and interneuron defects in <i>lron-11</i> mutants.

Panels A, C, E, G, I, K show wildtype, panels B, D, F, H, J, L show lron-11 mutants. The anterior side of the animals are towards the left of the image, the left side of the animals is towards the top of the image. Scale bars: 20μm. A, B: VNC visualized with the pan-neuronal marker evIs111[rgef-1::GFP]. A) In wildtype animals axons do not cross between left and right axon tracts. B) in lron-11(ok2333) mutant animals axons cross between the left and right axon tracts (arrows). C, D: DNC visualized with the pan-neuronal marker evIs111[rgef-1::GFP]. C) In wildtype animals axons are tightly fasciculated. D) in lron-11(ok2333) mutant animals axons are partially defasciculated (arrows). E-H: Pioneer axons (PVPR and AVG) visualized with hdIs26[odr-2::CFP & sra-6::DsRed2]. PVPR is the fainter axon in the left tract. AVG is the brighter axon below it, in the right tract. E) In wildtype animals PVPR crosses from the right tract into the left tract close to the posterior end of the VNC (arrow). F) In lron-11(ok2333) mutant animals the PVPR axons sometimes crosses into the left tract at a much more anterior position (arrow, ‘late separation defect’) close to the vulva (marked with a ‘v’). G) In wildtype animals pioneer axons stay in their axon tracts. H) In lron-11(ok2333) the PVPR axon sometimes crosses into the right axon tract and then back into the left axon tract (arrows). I-L: Command interneuron axons visualized with rhIs4[glr-1::GFP]. I) In wildtype animals CI axons entering the VNC from the nerve ring (nr) on the left side cross into the right axon tract anterior to the retrovescicular ganglion (rvg). J) In lron-11(ok2333) mutant animals, some CI axons are late crossing into the right tract (arrow). K) In wildtype animals all CI axons extend in the right axon tract (‘v’ marks the position of the vulva). L) In lron-11(ok2333) mutant animals, some CI axons cross into the left tract at various positions and sometime cross back (arrows).