Acute organotypic cortical slice culture experiments were performed essentially as described (Flynn et al., 2009). We added 106–107 pfu of Cofilin-RFP or RFP control adenovirus directly on the brain tissue at 24 hr and the tissue was fixed and stained at 72 hr. Primary mouse hippocampal and cortical CB-839 concentration neurons were dissected from E16.5–E17 brains and cultured as previously described (Garvalov et al., 2007). The DeltaVision RT (Applied Precision) setup was primarily used for live-cell imaging of fluorescent proteins. Neurons from Lifeact-GFP transgenic mice (Riedl

et al., 2010) were used to visualize actin dynamics. In other experiments, AC KO neurons or wild-type littermate controls were transfected with Lifeact-GFP and/or EB3-mCherry to label the actin and growing microtubules, respectively. GDC-0199 Rescue experiments with Cofilin-DD were performed on AC KO neurons cotransfected with Lifeact-GFP and pTuner Cofilin-DD or empty pTuner plasmid (Clontech). Indirect immunofluorescence was performed under conditions optimal for the preservation of the cytoskeleton. Neuronal cultures were fixed with 4% paraformaldehyde, 4% sucrose in PHEM fixation buffer and prepared for immunofluorescence (Witte et al., 2008). Local actin destabilization was achieved by application

of a local field of latrunculin B essentially as described (Bradke and Dotti, 1999). The ultrastructural analysis of the actin cytoskeleton was essentially performed as described (Auinger and Small, 2008) with minor modifications for optimal preservation of the neuronal cytoskeleton. The cortices of E16.5–E18 embryonic brains were rapidly dissected and resuspended in SDS lysis buffer and prepared for SDS-PAGE and western blotting. Relative levels of filamentous and globular actin were determined using the F:G actin kit from Cytoskeleton according to the manufacturer’s guidelines. We are very grateful for the technical assistance of Ralf Zenke, Ireen König, and Hans Fried. Frank Gertler, Franck Polleux, and Gerard Marriott receive our appreciation for reagents supplied in this study. We thank Barbara Bernstein, Mark Hübener, Artur Kania, Claudia Laskowski,

Klemens Rottner, Michael Sixt, and Michael Stiess for helpful comments and suggestions on the manuscript. Tryptophan synthase Xiao-bing Yuan (Shanghai Institute for Biological Sciences) is gratefully acknowledged for instruction in utero electroporation techniques. We gratefully acknowledge support from the Marie Curie Actions (K.C.F.), the Max Planck Society (F.B), the Deutsche Forschungsgemeinschaft (F.B. and W.W.), and Austrian Science Fund (FWF to J.V.S.). “
“Neuronal migration is a directional process achieved by periodic translocation of the cell body within a long thin exploring process. We and others have described two main steps in the cell body translocation (Solecki et al., 2004; Bellion et al., 2005; Schaar and McConnell, 2005; Tsai et al.