Fig. 5. zip reduces tasiR-ARF levels and increases ETT and ARF4 expression. (A) Northern analysis of zip-2, sgs3-11 and rdr6-11 shows that all three reduce levels of tasiR-ARF, whereas only sgs3 and rdr6 reduce levels of the TAS2 product siR1511. 5'RLM-RACE demonstrates that the reduction in tasiR-ARF correlates with a reduction in the cleavage of the ETT transcript. (B) Northern analysis of tasiR-ARF and ETT RNA at different times in rosette development in continuous light. (C) RT-PCR analysis of ETT and ARF4 RNA from successive 3-mm leaves of wild-type and zip plants grown in short days. zip-2 causes a consistent level of increase in both ETT and ARF4 expression, but both genes are expressed uniformly in successive leaves. The ratio of the signal relative to the loading control eIF4a is shown. (D) RT-PCR analysis of ETT and ARF4 RNA from leaves of wild-type and zip-2 plants grown in continuous light.