Cystin, a novel cilia-associated protein, is disrupted in the cpk mouse model of polycystic kidney disease
J. Clin. Invest. Xiaoying Hou, et al. 109:533 doi:10.1172/JCI14099 [Go to this article.]

Figure 2
Organization of the cpk genomic sequence and identification of the cpk mutation. (a) Alignment of the cpk cDNA, the UniGene consensus sequences, and the BAC genomic sequence demonstrated that the cpk gene is encoded in five exons spanning 14.4 kb of genomic DNA. The first nucleotide of the cDNA corresponds to the first nucleotide of exon 1, which spans 1,184 bp and is the largest of the five exons. This exon contains an ATG start site that lies within a Kozak consensus sequence (CGCGCCatgG). The 435-bp ORF extends into exon 3. Exons 4 and 5 are apparently untranslated, and a putative cryptic splice site (gaacagCTG) within exon 5 appears to account for the 1,856-bp and 1,786-bp (gray box) splice variants. An atypical polyadenylation signal (ATTAAA) lies 22-nt upstream of the poly(A⁺) tail. Of note, the microsatellite marker, D12Mit12, lies within intron 1 of the cpk gene. (b) PCR amplification and direct sequence analysis identified tandem 12-bp and 19-bp deletions in exon 1 of the cpk gene. The comparative sequence is indicated in b text. The resulting frameshift truncates the predicted protein. The position of the PCR primers is identified by arrows. The putative Kozak sequence is underlined and iized. (c) Primers flanking the tandem deletion in the cpk mutant allele amplify a 351-bp product from wild-type (B6 and D2) DNA, a 320-bp product from B6-cpk/cpk DNA, and both bands from B6-+/cpk and F₁ +/cpk heterozygotes. In the key F₂ cpk/cpk recombinants (R1–R5), only the 320-bp mutant allele was amplified.