Figure 1.

Targeted disruption of the SV2A gene. (A) Strategy for generating SV2A-minus mice. A portion of the SV2A gene was isolated by screening a mouse 129SV genomic DNA library with a probe corresponding to the 5′-end of the rat SV2A cDNA. The exon containing the translation start site is depicted as a black box. A targeting construct was generated in which this exon and surrounding DNA were replaced with a gene encoding neomycin resistance. To allow for negative selection, a gene encoding thymidine kinase was placed at the end of the short arm of the construct. Homologous recombination of the construct resulted in a disrupted gene that produced a shorter fragment when digested with the restriction enzyme HindIII. Cells and animals were genotyped by Southern analysis of HindIII-digested genomic DNA probed with the DNA fragment depicted as a gray box above the schematic of the disrupted gene.H3, HindIII; X1, XbaI; A1, ApaI; S1, SpeI; neo, gene encoding neomycin resistance; TK, gene encoding thymidine kinase; w.t., wild type. (B) Southern analysis demonstrating disruption of the SV2A gene. Shown is a Southern analysis of genomic DNA isolated from two litters produced by mice heterozygous (+/−) for the SV2A gene disruption. DNA containing the disruption produces a smaller HindIII-digestion fragment. Genotypes are indicated at the tops of the lanes. Homozygous mutants are marked with an asterisk. wt, wild type.