short interfering RNAs are produced naturally in some plants and animals. Their job is to bind to messenger RNAs and stop them being translated into proteins. In normal circumstances this may be protective if a virus is trying to make its own proteins in a host cell but scientists are now using them to “knockdown” the expression of some genes. For example if you had a genetic disorder like Huntington’s disease where over production of a protein causes brain cells to die, you could insert some siRNA to stop that protein being expressed. However, we don’t currently have the technology to use them in humans and their main use in science is to investigate what role a certain gene/protein has and how the cells change when you remove the protein by blocking its production with siRNAs.
siRNAs are really important as they can stop a gene being expressed. A gene is a little sequence of DNA that normally gets made into a protein by our cells (so the gene is ‘expressed’.) The protein can then go and do its specific job like help make the cell strong or whatever it does. But siRNAs stop this protein being made. This means that siRNAs allow us to ‘knockdown’ the specific protein that we are interested in knowing more about and see what happens.
For example we use siRNAs in our lab to knockdown a certain protein called MCAK (not a very catchy name!) We found that when we block MCAK in eggs, the eggs go really dodgy. This told us that MCAK is really important for making healthy eggs so that was quite exiciting!