RNA Interference

So now that we know scientists use RNAi to see what proteins do in the cell, how does it really work?

Imagine you were working in a bakery making cookies (proteins). The head chef (DNA) wrote down the recipe for you so you wouldn’t forget it (mRNA). One day a 2yr old and all his friends come into the bakery. He finds the recipe and calls over his friends to cut it up (RNAi). Now you can no longer read what it says, and you can’t make any more cookies. This is how the process of RNA Interference takes place.

Scientists can introduce new RNA (*the copy of the DNA that can leave the cell to make proteins) into the worm's eggs by using the bacteria they eat. The new RNA enters the cell after the worms eat the bacteria and targets the mRNA the cell makes normally. As you remember, genes are made up of a sequence of letters like ATGCGTAC. The new RNA has a sequence of letters that compliments (like G goes with C etc) the mRNA made by the cell. The added RNA binds to the mRNA made by the cell like two large puzzle pieces fitting together. This makes a double stranded piece of RNA which is a warning flag for the cell. The cell has evolved specific proteins (dicer) whose task is to destroy any double stranded RNA they find. The evolution of this protein helps organisms survive because many viruses infect cells by inserting double stranded RNA. Therefore, this amazing experimental method takes advantage of a naturally existing protein and process
that cells evolved a long time ago.
These specific proteins see the warning and cut up the mRNA so the ribosome can't read it and no proteins can be made. *If you remember, mRNA goes into the ribosome and that is where the amino acids (ingredients) are put together to make the protein* The cut up pieces of RNA can't be made into a protein the cell can use.

Watch this simulation and you will see how this process is acted out inside the worm cell!

How do you think this can affect the worm?