Double Stranded RNA, dsRNA and RNA Interference RNAi,Phenomenon,Organisms,Post Transcriptional Gene Silencing,Nucleotides

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Triplex DNA, TFOs, PNAs, RNA-DNA Hybrids and dsRNA - RNAi Triplex DNA, TFOs, PNAs, RNA-DNA Hybrids and dsRNA - RNAi - Introduction Triplex DNA and TFOs H Form or H DNA PNAs Peptide Nucleic Acids PNA DNA and PNA RNA Hybrid Complexes Synthesis of PNAs by BOC or Fmoc Protocols Modification of PNAs for Specific Uses

Home >> Biotechnology and Genomics >> Triplex DNA, TFOs, PNAs, RNA-DNA Hybrids and dsRNA - RNAi >> Double Stranded RNA (dsRNA) and RNA Interference (RNAi)

Your Ad Here	Double Stranded RNA (dsRNA) and RNA Interference (RNAi) During 1998-2001, it was shown that a small double stranded RNA (dsRNA) molecule can induce a potent and specific gene silencing both in animal and plant systems. The phenomenon was described as RNA interference (RNAi), which can be induced artificially by introducing a dsRNA. It has been experimentally shown that in majority of organisms, injection of a dsRNA longer than 500bp suppresses the expression of a gene having complementory DNA sequence, but has no effect on genes having unrelated sequences. The silencing of genes is achieved at the post-transcriptional level and the phenomenon therefore, is also described as post-transcriptional gene silencing (PTGS).
It has been discovered that dsRNA is processed into discrete -21-25-nucleotides long RNA fragments, which are complementary to both the sense and antisense sequences of double stranded DNA constituting the silenced gene, thus suggesting that it is derived from dsRNA. This small 21-25bp long RNA molecule associates with a protein and forms a multicomponent nuclease complex, called RNA-induced silencing complex (RISC), which destroys mRNA homologous to RNA component (dsRNA) of this complex. The protein component of RISC was shown to be a member of the agronaute family of proteins, which are essential for gene silencing in a variety of organisms.
Atleast a dozen genes that have been shown to exhibit dsRNA response, include the following: mut-16. mut-7, qde1, qde2, qde3 (a helices), SDEI/SGS2, SDE3, SDE3, ego-1 (RNA dependent RNA polymerase), rde-1, AGO1, etc In order to introduce dsRNA for gene silencing, gene constructs have been prepared in transformation vectors that would produce dsRNA. Using this approach, constructs expressing dsRNA corresponding to four genes (AGAMOUS or AG, CLAVATA3, APETALAI and PERIANTHA) were prepared and used for Agrobacterum-mediated transformation in Arabidopsis thaliana.	Your Ad Here
Gene specific heritable genetic interference was observed. This phenomenon of RNAi can be used for silencing deleterious genes and has already been used for inhibiting gene expression with an objective to elucidate the function of genes – a functional genomics approach.

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