Figure 1

Different cerebellar layers can be targeted by ex ovo electroporation. The cerebellar anlage is positioned right under the bifurcation of the middorsal sinus and the middle cerebral vein. (a) The injection site is indicated by +. The head of the embryo was turned and stabilized with a hook prepared from a spatula (arrowhead). (b) Tweezer electrodes were placed parallel to the head. It was important to avoid contact between embryo and electrode (indicated by white brackets) to prevent tissue damage. (c,d) One half of the cerebellum was successfully transfected by electroporation. The untransfected half of the cerebellum could serve as an internal control for the analysis of phenotypes. (d) Successful transfection of one half of the cerebellum after ex ovo electroporation with platelet electrodes is shown in a 250-μm-thick coronal slice. (e-i) Depending on the depth of the injection, different cerebellar layers could be targeted: deep injections into the ventricle resulted predominantly in transfection of the ventricular zone labeling all cell types proliferating and migrating from there, such as Purkinje cells, interneurons, and glia cells (e). With superficial injections the developing ML (f,g) and granule cells of the external germinal layer (h,i) were transfected. Parallel fibers in the developing ML were visualized using AX-1 as a marker (g). Granule cells were identified by Pax6 (i). EGL, external germinal layer; ML, molecular layer; PS, pial surface; V, ventricle. Bar: 2 mm in (a,b), 1 mm in (c), 500 μm in (d), 100 μm in (e-g), 50 μm in (h,i).