PLM over extension and early termination defects are observed at the L1 larval stage.

<p>(A) L1 larva expressing <i>mec-4;;gfp (zdIs5)</i>. Anterior is to the left. Solid arrow points to where the PLM axon ends. The ALM cell body and the anterior end of the PLM axon are shown in each panel. A line diagram corresponding to the morphology of the neuron is shown to the right. The dashed lines in all panels represent the wild-type PLM termination boundary. In wild-type L1s (top <i>gfp</i> panel) the PLM axons are between 103 and 114 µm in length, and terminate at a region anterior to the tip of the ALM cell body. <i>vab-1(dx31)</i> mutants (middle <i>gfp</i> panel) have L1 PLM axons that overgrow beyond the normal wild-type range. Animals that over express VAB-1 (MYR-VAB-1) (bottom <i>gfp</i> panel) have L1 PLM axons that are significantly shorter (undergrowth) than wild-type. (B) <i>vab-1</i>, <i>nck</i>-1 and <i>wsp-1</i> L1s have PLM axons that are overgrown beyond the normal range. (C) The <i>nck-1(ok694)</i> and <i>wsp-1(gm324)</i> alleles significantly reduced the undergrowth defects caused by MYR-VAB-1. Error bars indicated the SEM, and significant differences between some of the strains were compared (using student's t-test), **P<0.01; ***P<0.001. ‘N’ refers to the number of axons scored.