Interference starts when a piece of double-stranded RNA
, either present naturally in a cell or injected by researchers, bumps into an enzyme called dicer, which circulates inside a cell's fluid contents.
Virus-like, double-stranded RNAs
in the parasitic protozoan Cryptosporidium parvum.
If they know a gene's DNA sequence, they can easily create the double-stranded RNA
needed to silence the gene.
The interferon response is a natural cellular defense mechanism that responds to double-stranded RNA
, as in a virus, by shutting down many normal functions.
It has turned out that most, if not all, of this gene-blocking effect is actually triggered by the double-stranded RNA
that researchers inadvertently create when they produce either the sense or antisense strands.
RNAi, a form of double-stranded RNA
that can inhibit gene expression in a sequence-specific manner, was co-invented by Sequitur's scientific advisor Prof.
This tiny alteration helped the enzyme resist heat, thus enabling it to prosper in the digestive system, but also made it one-fifth as efficient at processing double-stranded RNA
Mello, co-recipients of the Wiley Prize in 2003, received the 2006 Nobel Prize in Physiology or Medicine for their discovery of RNA interference - gene silencing by double-stranded RNA
RNAi is a form of double-stranded RNA
that causes sequence-specific inhibition of target mRNAs.
For more than a decade, plant pathologists have recognized that the less deadly chestnut blight contains double-stranded RNA
- a virus of sorts - in its cells.
It uses double-stranded RNA
as a trigger to degrade messenger RNA (mRNA), the molecules that link DNA's genetic instructions and the production of proteins.
The added sequence will bind up the messenger RNA with the same powerful bonding that holds together a DNA double helix, thus creating a freak double-stranded RNA
or a DNA-RNA hybrid.
With RNAi, the trigger molecule is a double-stranded RNA
, which is inherently more stable and should therefore be effective at lower doses.
Made by mismatching periodic regions on a double-stranded RNA
, the drug is thought to have broad cellular effects, including induction of antiviral enzyme production and release of factors like interferon.
siRNA are double-stranded RNA
of approximately 20 base pairs that block or decrease the expression of specific gene targets.