The difference in the cytoskeletal machinery of growth cones of growing axons and leading processes

In this study, we compared axonal elongating growth cones and leading process growth cones in the same conditions that manipulated filopodia, lamellipodia and drebrin, the latter mediates actin filament-microtubule interaction. Cerebral cortex (CX) neurons and medial ganglionic eminence (MGE) neurons from embryonic mice were cultured on less-adhesive cover glasses. Inhibition of filopodia formation by triple knock down of Mena, ENA and VASP or double knock down of Daam1 and fascin affected axon formation of CX neurons but did not affect the morphology of leading process of MGE neurons. On the other hand, treatment with CK666, to inhibit lamellipodia formation, did not affect axons, but destroyed the leading process growth cones. When drebrin was knocked down, the morphology of CX neurons remained unchanged, but the leading processes of MGE neurons became shorter. In vivo assay of radial migration of CX neurons revealed that drebrin knock down inhibited migration, while it did not affect axon elongation. These results showed that filopodia-microtubule system is the main driving machinery in elongating growth cones, while lamellipodia-drebrin-microtubule system is the main system in leading process growth cones of migrating neurons.

Source: Developmental Neuroscience - January 31, 2022 Category: Neuroscience Source Type: research