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The mechanism of RNAi

The mechanism of RNAi. by Renchang. Guo S et al, a gene required for establishing polarity in C. elegans embryos, encoding a putative Ser/Thr kinase that is asymmetrically distributed, cell, 1995, 81:611. Fire Andrew, et al, Potent and specific genetic interference

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The mechanism of RNAi

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  1. The mechanism of RNAi by Renchang

  2. Guo S et al, a gene required for establishing polarity in C. elegans embryos, encoding a putative Ser/Thr kinase that is asymmetrically distributed, cell, 1995, 81:611

  3. Fire Andrew, et al, Potent and specific genetic interference by double-strand RNA in Caenorhabditis elegans. Nature, 1998, 391:806-811

  4. RNAi is characteristic of: Extreme efficiency: a few trigger dsRNA molecules suffice to inactivate a continuously transcribed target mRNA for long periods of time; Long-lasting: the inactivation persists through cell division, spreads to untreated cells and tissues of plants, and is even inhetited by subsequent generations of nematodes.

  5. Bernstein, 2001 Hamilton, 1999 ? Cogoni, 1999 Smardon, 2000 Dalmay, 2000 Lipardi, 2001 Nykanen, 2001

  6. Sijen, 2001

  7. Hamilton, A.J., et al, A species of small antisense RNA in posttranscriptional gene silencing in plants. 1999, Science, 286, 950-952.

  8. Bernstein E, et al, Role for a bidentate ribonuclease in the initiation step of RNA interference. Nature, 2001, 409:363-366 Dicer: a dsRNA-specific endonuclease responsible for processing of long targeting dsRNA into siRNAs.

  9. Cogoni, et al, Gene silencing in Neurospora crassa reqiures a protein homologous to RNA-dependent RNA polymerase, Nature 399, 166-169 QDE-1 N. crassa

  10. Smardon. A., et al, EGO-1 is related to RNA-directed RNA polymerase and functions in gern-line development and RNA interference in C. elegans. 2000, curr.Biol. 10, 169-178. EGO-1, C. elegans

  11. Cell, Vol. 101, 543-553

  12. Material: Arabidopsis, transgenes PVS:GFP: responsible for initiation of PTGS GFP: reporter of silencing Four genetic loci are requried for PTGS Sde Silencing defective Sde1, Sde2, Sde3, Sde4

  13. This paper first proves that siRNA serves as primers to transform the target mRNA into dsRNA. The nascent dsRNA is degraded to Eliminate the incorporated target mRNA while generating new siRNAs in a cycle of dsRNA synthesis and degradation. Drosophila GFP Pp-Luc Photinus pyralis luciferase

  14. Proved the nascent RNA is double stranded..

  15. AAAA-3’ 5‘ Beyond upstream siRNA’s antisense strand The polarity of the RdRP reaction

  16. Puzzlement How the ds siRNAs anneal to ss RNA? Whether Target dsRNA can self replicate? How to control the secondary RNAi? How to explain the long-lasting of RNAi?

  17. Good night

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