Fig. 4 Slc16a6a is a β-hydroxybutyrate transporter. (A) RT–PCR of mature slc16a6a and rpp0 transcripts at the indicated ages. (B) Whole-mount in situ hybridization with slc16a6a riboprobes. (C) The topology of the predicted wild-type and hypothetical rmn Slc16a6a proteins. (D) Ponceau S staining of nitrocellulose membranes following transfer of proteins resolved by sodium dodecyl sulfate polyacrylamide electrophoresis. (E) Immunoblotting with custom anti-Slc16a6a IgGs of the membrane in D. The membrane was deliberately overexposed in order to increase the chance of detecting a smaller protein band in the rmn mutant. (F) Current tracings of Xenopus oocytes expressing Slc16a6a (or control-injected oocytes, in black) that were perfused with monocarboxylic acids (5 mM) for the indicated time period. Oocytes were voltage-clamped to a holding potential of 70 mV. (G) Current–voltage relation of a Slc16a6a-expressing oocyte perfused with β-hydroxybutyrate.