RT-PCR analyses of alternative splicing of Dmbt1. There are two known transcript isoforms for this gene: the short isoform designated in Ensembl as Dmbt1-201 and the long isoform Dmbt1-202, which has four additional exons (shown with the black arrows). A, Two sets of primers were designed on either side of exons 2 and 7 that were shown to be alternatively spliced in response to the high SF diet. Primer location and expected products are shown. Both sets of primers were designed to give a defined product from the long Dmbt1 isoform but no product from the short isoform. B, Gene expression of Dmbt1. After eight weeks, there was a significant effect on expression of the DMBT1 transcript by PTEN genotype (p > 0.001), SF (p = 0.008), and by a PTENxSF interaction (p = 0.007). C, Amplified products from five-week old (i, iii) and eight-week old (ii, iv) mice show the effect of diet on the Dmbt1 loci flanking exon 2 (i, ii) and exon 7 (iii, iv). Note that during amplification of the locus flanking exon 7 there is a high MW product that corresponds to the presence of genomic DNA. However, the 493 bp mRNA product corresponding to the long Dmbt1 isoform is preferentially amplified.