1. Dicer-Like A RNA Helicase Gene Involved in Gene Silencing UCSF Max BachourJessica ChenChris McQuilkin

2. RNA helicase is an enzyme that unwinds RNA and modifies its structure Involved in transcription, splicing, translation, and gene silencing A RNA Helicase Gene Involved in Gene Silencing

3. How does Dicer-Like Help with Gene Silencing?

4. RNA interference Dicer and Dicer-Like (DCL) enzymes are involved in RNA interference (RNAi) Nontranslated RNA fragments bind to mRNA and prevent translation into a protein

5. Evolutionary Origins A defense system for eukaryotes against double stranded viruses and transposons

6. What is Dicer’s role in RNAi? Activated by exogenous double-stranded (ds) RNA miRNA (micro RNA) -small, non-coding regions of double-stranded (ds) RNA 21-22 nucleotides

8. What is Dicer’s role in RNAi? siRNA (small interfering RNA) non-coding regions of dsRNA 20-25 nucleotides in length

9. What Happened When the Dicer-Like Gene Was Knocked-out? Seed from a Wild Type Plant

10. Dicer-Like Mutants Cone Shaped Suspensor

11. How did the Dicer Knock-out Result in the Cone Shape? Knocking-out the dicer gene keeps RNAi from forming This keeps certain genes in the seed from being inhibited. The lack of inhibition caused the cells in the embryo to multiply irregularly

12. Why did we knock-out dicer? Provided a positive control to compare to our T-DNA knock-out line Made sure that negative results weren’t due to technical failure Our main goal is to discover the function genes in arabidopsis.