An HSPG network influences D-type motor axon guidance.

<p>A: Summary of relevant single and double mutants. All the single mutants have no or only minor defects, meaning that on average no more than one commissural axon fails to reach the dorsal nerve cord (DNC). The dashed line at 5 commissures per animal indicates the limit separating the single mutants from the weak enhancers. Weak enhancers (one to two commissural axons fail to reach the DNC, limit indicated by dashed line at 4 commissures per animal) are double mutants that are considered not to play an important role in D-type axon guidance. Strong enhancers have very clear D-type axon guidance defects (the dashed line at 2 commissures per animal is to allow for distant bars to be visually comparable). Statistical test results are indicated as follows: ns = not significant, * = p<0.05, ** = p<0.005, *** = p<0.0005. Superscripts (also shown in the bars of the corresponding strains) indicate to which strain the comparison was made: 1: <i>hse-5</i>(tm472), 2: <i>sdn-1</i>(zh20), 3: <i>cle-1</i>(cg120), 4: <i>hst-2</i>(ok595), 5: <i>lon-2</i>(e678) <i>sdn-1</i>(zh20). B-E: Representative pictures of wild type (B), <i>sdn-1</i>(zh20) (C) and <i>hse-5</i>(tm472) (D) single mutants and the strongest enhancer <i>hse-5</i>(tm472)<i>; sdn-1</i>(zh20) (E). The transgene <i>oxIs12</i> is present in all backgrounds. F: HSPG core proteins and HS modifying enzymes can be placed into two groups based on the strength of the D-type motor axon guidance defects observed in double mutants. Only the double mutants of the group of strong enhancers are considered for this network. For a complete set of strains see Figure S2. Grey bars in A represent the number of commissural axons growing away from the ventral nerve cord (VNC); white bars indicate the number of commissural axons reaching the DNC. Numbers are from 50 L1 animals +/- SEM.