Fig 1: Methylenetetrahydrofolate reductase (Mthfr) mRNA expression. (a) Quantitative PCR analysis of Mthfr mRNA expression normalized to actin in SS-WT or SS-Clcn6 rats on a normal salt (NS) or high salt (8% NaCl, HS) diet, N = 5 rats. The gene encoding Mthfr has 2 start codons in close proximity to Clcn6, so primers were designed to identify the (b) longer (X1, X2) and (c) shorter (X3, X4) isoforms of Mthfr and quantify their expression. Data are presented as Mean ± SEM, significance determined by one-way ANOVA with Holm-Sidak's multiple comparisons test, *p < 0.05, **p < 0.01, ***p < 0.001.