FIG. 7.

Activation of NMD results in the rapid decay of substrate transcripts. Quantitation of the relative levels of Nmd2p (•) and nonsense-containing mRNAs before and after the activation of NMD (by the addition of galactose): ade2-1 mRNA (○), pgk1 mRNA harboring an early nonsense codon (▪), and pgk1 mRNA harboring a late nonsense codon (□). The data for this graph were derived from the Northern blots of Fig. 4A (ade2-1) and 6A (early and late pgk1) and from the Western blot of Fig. 2 (Nmd2p).