Figure 1

his7-1 mRNA accumulated when nonsense-mediated decay is inhibited. Nothern blotting was used to assess the effect of UPF1 deletion on the accumulation of his7-1 mRNA. Total RNA was isolated from strain 5B-D1645 (his7-1 upf1Δ) transformed with plasmids pRS316 and pRS316/UPF1, designated as (upf1Δ) and (UPF1), respectively. Northern blots were hybridized with radiolabeled HIS7, ADE1, ACT1 and CYH2 probes. A. Representative hybridization signals specific to his7-1 mRNA (upper panel), ade1-14 mRNA (middle panel) and actin mRNA (ACT1) used as an internal control (lower panel) are shown. Numbers indicated under upper and middle panels represent the relative abundance of his7-1 and ade1-14 mRNA's, respectively, in upf1Δ and UPF1 strains. (s.d.) – standard deviation. B. Accumulation of CYH2 precursor mRNA was used to control that NMD is altered in the upf1Δ strain. The CYH2 probe detects both precursor and mature CYH2 mRNA. The fold increase in CYH2 precursor/mature mRNA accumulation in upf1Δ strain relative to UPF1 strain is indicated with the standard deviation (s.d.).