Generation and molecular characterization of the Nogo deletion mutant. A , The strategy to obtain the Nogo deletion allele via two consecutive gene targeting steps followed by Cre-mediated excision. A, B, C above the exons (black bars) refer to Nogo isoforms. Dotted lines, Splicing pattern for the Nogo-C transcript; Neo, neomycin resistance gene; Hprt, hypoxanthine phosphoribosyltransferase gene; IRES, internal ribosomal entry site; GFPLacZ, green fluorescent protein and β-galactosidase fusion gene; small arrows, primers used to analyze the Nogo-C transcript by RT-PCR. Two Frt sites flanking Hprt are omitted for simplicity. B , Northern blot with a C-terminal common probe. Nogo-A,B,C transcripts run at 4.7, 2.6, and 1.7 kb, respectively. Arrowheads indicate a slightly shorter, mutated form of Nogo-C transcript. WT, Wild type. C , RT-PCR to confirm the absence of Nogo-C transcript in the Nogo deletion mutant. D , Western blot analysis on Nogo-A, NgR1, MAG, and OMgp in Nogo-A,B gene-trap and Nogo deletion mutants. α-tub, α-Tubulin.