Figure 6. Endoglycan reduces the adhesive strength of commissural neuron growth cones.

(A) Example of snapshots taken before and after growth cone blasting of mRFP-positive commissural neurons cultured on a HEK cell layer (shown in the brightfield channel). White arrowheads and asterisks show the location of the growth cone and the approximate location of the micropipette tip, respectively. (B) Control mRFP-transfected commissural neurons were plated either on a layer of control HEK cells or HEK cells expressing Endoglycan. The time it took to detach a growth cone from the HEK cells was taken as a measure for the adhesive strength. The adhesion of growth cones to HEK cells expressing Endoglycan was significantly reduced (0.59 ± 0.26 compared to 1 ± 0.61 on control HEK cells). N(replicates)=3, n(growth cones)=40 (HEK^Ctrl) and 50 (HEK^Endo-myc). (C) Similar observations were made when commissural neurons were transfected with Endoglycan instead of the HEK cells. Detachment was faster for growth cones of mRFP-transfected neurons co-transfected with Endoglycan and plated on control HEK cells (0.83 ± 0.33) compared to control neurons transfected only with mRFP (1 ± 0.41). N(replicates)=6, n(growth cones)=52 (CN^Ctrl) and 51 (CN^Endo-myc). *p<0.05, ****p<0.0001, Two tailed Mann-Whitney test. Error bars represent standard deviation. CN, commissural neuron; Ctrl, control. Scale bar: 50 μm. Source data and statistics are available in Figure 6—source data 1 spreadsheet.