Mutation in sph^2BC.

(A) Top, schematic representation of the Spna1 cDNA with numbers above the line corresponding to the repeats of 106 aa that comprise the α-spectrin protein. Exon numbering infers correspondence to the human. Arrow above the line shows the location of exon 41. Shown below the cDNA schematic is nucleotide (top) and amino acid (bottom) sequence of the +/+ andsph^2BC/sph^2BC cDNAs in the vicinity of the exon 41 skip. Double hatch marks (//) denote sequences not represented in the figure; numbers of base pairs (bp) and amino acids (aa) not represented are shown between the hatch marks. (B) α-Spectrin genomic sequence at the exon 41/intron 41 boundary obtained from spleen DNA of wild-type (+/+) andsph^2BC/sph^2BC mice. Upward arrow denotes exon 41/intron 41 boundary. The mutated base in thesph^2BC allele is marked by an underline and an asterisk. (C) Representative genomic PCR of tail DNA from +/+ andsph^2BC/+ mice. Lane M is marker; sizes in kb are shown on left. Lanes labeled 53: PCR products from a reaction containing primers (53 and 54) that amplify wild-type and mutant alleles of Spna1. Lanes labeled 52: PCR products from a reaction containing primers (52 and 54) designed to identify the G→T transition in the sph^2BC allele. Genotype of mice is noted above each bracketed pair of reactions.