Trans-acting siRNA Brett Johnson BMS265

Trans-acting siRNA is just like “normal” siRNA

Trans-acting siRNA is just like “normal” siRNA …except for when its not.

Discovery

ta-siRNAs come from TAS genes Biogenesis ta-siRNAs come from TAS genes

Trans-acting siRNAs act in trans! Mechanism of Action Trans-acting siRNAs act in trans!

Cellular Functions All ta-siRNAs from a TAS gene tend to have similar targets. Four TAS families in Arabidopsis: TAS1 regulates at least 5 different targets of unknown function TAS2 targets 2 Pentatricopeptide Repeat (PPR) proteins of disputed function TAS3 targets three Auxin Response Factor (ARF) genes (tasiR-ARF) TAS4 targets MYB transcripts (cell cycle, metabolism)

Evolution and Conservation TAS1 and TAS2 ta-siRNAs are unique to Arabidopsis TAS3 is conserved in rice, Arabidopsis and maize (monocot vs. dicot lineages) miR390 directed biogenesis of ta-siRNAs is conserved in moss (400 million years)

Potential as a Tool Replaced the ta-siRNAs in TAS1c and silenced FAD2 activity to levels comparable to a null mutant

There’s More!

There’s More! Read the wiki.