Disruption of the Sphk2 gene in the mouse genome by homologous recombination. (A) Schematic representation of the mouse Sphk2 locus before and after recombination. Homologous recombination removes exons 3 to 6. (B) Detection of knockout and WT alleles by PCR analysis of genomic DNA; bands of 511 and 733 bp are expected for +/+ and -/- animals, respectively, and both bands for heterozygotes. Locations of primers are indicated in panel A. (C) mRNA expression of Sphk1, Sphk2, Sgpp1, Sgpp2, Sgpl1, Cerk, Smpd1, Smpd2, and Smpd3 in kidneys of Sphk2^-/- mice relative to WT as determined by quantitative real-time PCR. The data represent mean values ± SD, n = 3.