Expression of RNA silencing pathway genes in Arabidopsis mature pollen. ACT1(ACTIN1) was used as a positive control to ensure the quality of RNA and cDNA. PCR products amplified from cDNA are indicated by asterisks. Sequences for the cDNAs were confirmed by cloning and sequencing. PCR products at higher molecular weight in each sample were amplified from genomic DNA. DCL: Dicer-like; AGO, Argonaut; RDR, RNA-dependent RNA polymerases; DRB, Double-stranded RNA binding protein. AGO3, RDR1 and DRB2 were not detected.