Mutations in FBW2 suppress hypomorphic ago1 mutations. (A) Eighteen-day-old rosettes of ago1 mutants and ago1 fbw2-1 double mutants. The shapes of leaves 1-4 are also illustrated. (B) The number of juvenile, adult and cauline leaves in ago1 and ago1 fbw2-1 double mutants (± standard deviation). (C) 14-day-old fbw2-1, ago1-36 and ago1-36 fbw2-1 double mutants grown on MS media. (D) Relative abundance of microRNA (miRNA) targets in various genotypes as measured by quantitative-real time polymerase chain reaction in 14-day-old (top) or 20-day-old (bottom) rosettes. Target genes were normalized to EIF4. Actin was used as a non-target control (± standard deviation). (E) Small RNA blots of low-molecular-weight RNA isolated from 14-day-old or 20-day-old rosettes probed with oligonucleotides complementary to specific miRNAs. Methionyl transfer RNA was used as a loading control.