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Fig. 1. Growth cones contain F-actin-rich foci within their central domain in vitro and in vivo. (A,B) Confocal images of phalloidin-labeled spinal neuron (A) or retinal ganglion cell (B) growth cones with F-actin foci (arrowheads) cultured on different substrata. (C,D). Quantification of foci number (C; n≥26) and area (D; n≥51) in growth cones on different substrata. Lines represent the mean intensity. (E) TIRF images of a live spinal growth cone on laminin expressing GFP-β-actin. Note stable F-actin foci in the C-domain as the growth cone advances (red boxes). (F,G) Confocal z-series projections of whole-mount Xenopus spinal cords with F-actin-labeled motoneurons and commissural interneurons by using targeted expression of mCh-UtrCH. (F) Lateral view shows motoneuron axons extending along the ventral fascicle with F-actin foci (arrowheads). (G) Ventral view of a spinal cord showing commissural interneuron growth cones at the midline. Scale bars: 5 µm (A,B,E,G); 10 µm (F). FN, fibronectin; LN, laminin; PDL, poly-d-lysine. |
