Rna interference double stranded rna molecules are

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Unformatted text preview: observation: double-stranded RNA molecules are much more potent inhibitors of gene expression. RNA interference Double-stranded RNA molecules are cleaved by Dicer The resulting small interfering RNAs (siRNAs) The antisense strand of the siRNA is bound by RISC (RNAinduced silencing complex) RNA interference RISC interacts with the target message, resulting in another dsRNA Which is cleaved by Dicer...etc. dsRNA is a catalyst for the destruction of all mRNA for that gene RNA interference RNAi happens in nearly all cell types, in all eukaryotes tested to date. Why might this have evolved? MicroRNAs (miRNAs) Similar to siRNAs, miRNAs are small RNA molecules that form a RISC to target the expression of a particular gene Unlike siRNAs, miRNAs are usually encoded by a cellular gene and probably function as a form of gene regulation Unlike siRNAs, miRNAs prevent translation (rather than lead to mRNA degradation) Feature siRNA miRNA Origin mRNA, virus, or transposon Distinct miRNA gene Cleavage of RNA duplex or ssRNA hairpins ssRNA that forms short ds hairpins Size 21-25 nucleotides 21-25 nucleotides Primary Action Degradation of mRNA Inhibition of translation Target Genes from which they were Genes other than those from transcribed which they were transcribed Protei...
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This document was uploaded on 02/25/2014.

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