Figure 1.

Isolation of RNA from frq⁺ and frq⁷ cultures representing four different times in the circadian day. (A) Densitometry of the clock-regulated ccg-1 mRNA isolated from N. crassa frq⁺ (solid line) and frq⁷ (dotted line) cultures grown in continuous dark and harvested every 4 hr (4). The time in the dark (Hours DD) is indicated on the bottom of the plot, and the corresponding CT is shown on the top for both strains. Arrows point to the time of harvest (DD37 and DD43) used to isolate mRNA for the generation of the time-of-day-specific cDNA libraries. (B) Northern blot hybridization of total RNA (10 μg) extracted from frq⁺ and frq⁷ strains at DD37 and DD43 representing approximate CT18, CT0, CT6, and CT12 as shown in A. Hybridization is to the clock-controlled eas(ccg-2) gene.