RNA Silencing is a conserved RNA-mediated and sequence-specific gene silencing effect by which gene expression is down-regulated by either microRNA (miRNA) or small interfering RNA (siRNA)
A small single-stranded non-coding RNA molecule
Inhibit translation of multiple mRNA targets
A small double-stranded non-coding RNA molecule
Highly specific with only one mRNA target
RNA Silencing Mechanism
dsRNA is first degraded by Dicer (a highly conserved RNase) into siRNA (~22 bp).
siRNA binds to RISC (RNA Induced Silencing Complex) to form siRNA-Protein Complex.
The Complex cleaves mRNA with complimentary sequence, inhibiting downstream expression.
A Successful RNA Silencing Expriment
The common methods of mammalian transfection include:
calcium phosphate coprecipitation
Currently, liposome transfection is most commonly used.
Notes for Liposome Transfection
Several aspects need to be paid attention to for liposome transfection:
the type and dosage of transfection reagent
the type and dosage of siRNA
the cell density
the operation sequence
the water bath timing of cells and siRNA-transfection reagent complex
Chemically Modified siRNA
The most difficult problem of RNAi technology is the stability of siRNA. Here, with chemical modification, our chemically modified siRNA has much higher stability than the common siRNA. The chemical modification not only enhances the life span of siRNA in serum and cell culture, but also enhances its activity in vitro.
Sirnafectamine Transfection Reagent
Sirnafectamine is a new generation of RNA transfection reagent, which can be used in RNA transfection experiment. Sirnafectamine accelerates the binding of glycoprotein on cell membrane, which promotes the endocytosis of cells. In addition, compared with other siRNA transfection reagents, Sirnafectamine has minimal cytotoxicity and the best cell state after transfection.