Fig. 3. Mutation detection in Lrp6. (A) Chromatograms show the C to T transition in rs. (B) PCR-based genotyping with HpaII digestion. In wild-type (BALB/c and C57BL/6 in lanes 1 and 2, respectively), the 458-base product from wild-type is cut into three fragments (205, 154 and 99 bases), while one from rs into only two fragments (359 and 99 bases) (Lane 4). Heterozygous specimens show four fragments (359, 205, 154 and 99 bases) (lane 3). (C) A schematic drawing of the Lrp6 protein structure with designations for known functional domains. The rs mutation resides right in front of the third EGF-like repeat. (D) The Arg (R) residue at the corresponding positions is highly conserved among various Lrp proteins. Designations after Lrp: M, mouse; H, human; D, Drosophila; F, Xenopus; C, C. elegans.