Figure 4.

Circadian accumulation of coumarin 7-hydroxylase mRNA. (Left) Ten micrograms of total liver mRNA isolated from C57BL/6 × 129/Ola mice at hours of the day indicated (6, 10, 14, 18, 22, 2) was analyzed by RNase protection for accumulation of coumarin 7-hydroxylase mRNA (351 nucleotides), using the same probe as in Fig. 3. Y, yeast RNA alone. (Right) In parallel, indicated amounts (3 to 0.03 fmol) of a synthetic RNA (ψ-RNA) corresponding to the coumarin 7-hydroxylase mRNA were analyzed by RNase protection with the same probe, generating a protected fragment of 366 nucleotides rather than 351, due to polylinker sequences. These signals were used to quantitate coumarin 7-hydroxylase mRNA accumulation in the mouse liver samples.