Biogenesis of nat-siRNAs that depend on DCL1. (a-c) Accumulation of nat-siRNA1g51400 (a), nat-siRNA2g41590 (b) and nat-lsiRNA4g34070 (c) is shown in various dcl, rdr, polIV and polV mutants. Total RNA (75 to 100 μg) was used for Northern blot analysis. LNA probes complementary to each nat-siRNA were used. U6 was an internal control to show equal loading. The same results were obtained from two biological replicates.