Relative expression of Slc35d3 in control and mutant tissues. (A-B) Multiple tissue Northern blots (Clontech) were treated with a 303-bp cDNA probe derived from nucleotides 1281 to 1583 of Slc35d3 cDNA together with a β-actin probe (below) as a loading control. Poly(A)–RNA was isolated from Melan-A melanocytes and C3H/HeSnJ brain for Northern blotting (C). Brain and spleen poly(A)-RNA blots (4 μg/lane) (D) were probed with the above Slc35d3 probe and a G3PDH probe (below). The apparent decreased expression of the 2.6-kb mRNA in control C3H brain tissue in this experiment compared with that of control brain tissue in panel C is due to the greatly decreased time (8 hours compared with 4 days) of exposure of this blot to film.