RNA Interference (RNAi)

ch.14- classes of rna (382, 428 + 14.5 small rna molecules participate i a variety of function)

ch. 17-17.5 gene regulation (514-516, 519-520)

ch.19-therapeutics (593-594, 598+)

rna interference: mechanism of gene and virus interference

siRNA pathway: small interfering pathway/

microRNA pathway

RNAi: post transcriptional gene silencing mechanism

gene silencing mechanism: silencing the gene and protein

rnai: no protein no virus

regulating at post transcriptional stage

rna regulation: rna degradation or interference

  1. sequence specific for rna interference (turns down gene expression)

plants and bugs for antiviral : dicer like-cleaves dsRNA, siRNA to RISC. -can injest dsRNA to genes so turn down expression of a gene. molecular biology gene knock down

RNA interference: regulating gene expression—and functions in antiviral defense(plants,worms)

not antivial in humans

  1. siRNA pathway (comes form virus or scientist)

    • virus, transposon, exogenous, dsRNA source

    • results in target mRNA cleavage

  2. miRNA pathway- help guide RISC

    • nucleus/ endogenous dsRNA source

    • results in translational repression

  3. transcriptional silencing: altering chromatin structure

-dicer (chops)

-risc - rna induced silening complex

argonaute

siRNAs- viral mRNA

microRNAs -silencing gene sielncing , pre microRNA

RNAi mechanism

micro rna- target 3’ UTR

sirna- target anywhere

dsRNA original

siRNA perfect complementarity

MicroRNA are cleaved from larger precursors (pri-miRNA) same 3’ UTR same target sequence

-imperfect base pairing

  • 3’UTR mRNA

siRNA chromatin remodeling, methylate histone proteins and inhibit transcription. relaxed or tightened.

RNA cleavage: RISC containing an siRNA, pair with mRNA molecules and cleavage to the mRNA

miRNA bind to 3’ UTR

RNAi natural mechanism? yes

experimentally? yes

treat diseases? yes

reduce infections?yes

how and what factors consider? -

plasmid: extra piece of dsDNA, circular. used for cloning genes, gene segments, protien production, etc.

siRNA therapy- used to treat heterozygous familia hypercholesterolemia

siRNA- promoter region only activated in roots makes dsRNA (only in roots), rna doesnt target in roots or us but worm eats it. dsRNA targets SNF7 gene and i is turned of and dies