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Fig. 3. Retroviral infection of heterogeneous primary cerebellar cultures is
specific for proliferating CGNPs. (A,B) Cultures pretreated with Shh vehicle
(Veh) alone prior to infection with GFP-carrying retroviruses showed only
5-10% infection levels (A), compared with
70% infection levels in cells
pre-treated with Shh (B). Merge of GFP-immunolabeled cells and DAPI-stained
fields (blue) are shown. (A) Several infected cells are highlighted
(arrowheads). (C,D) CGNPs infected with GFP retroviruses that
subsequently exit the cell cycle coexpress the neuronal marker, NeuN (FITC,
green) (C), but not GFAP (FITC, green), an astroglial cell marker (D),
indicating selective infection of neuronal precursors. After infection, cells
were treated with vehicle alone for 48 hours prior to immunostaining. (C)
Yellow pseudo-color indicates cells with overlapping expression (arrows); the
inset shows infected cell with typical granule neuron morphology at higher
power. (D) Arrowhead indicates a GFAP-positive cell. Note the paucity of
GFAP-positive cells; we observed no astroglia that co-expressed GFP under our
conditions of infection. (C',D') DAPI-staining (blue) of the
fields shown in C,D.