How do Scientists Study Proteins?
Imagine you were a scientist and wanted to study the role of a protein in the cell. Proteins are little construction workers in the cells of your body that help you do all these amazing things. They put things together or break them down (enzymes), they transport things around the cell like a car (transporter proteins), they communicate between cells, and they keep our cells nice and sturdy which allows us to stand up straight and tall. But like we talked about on the previous page, we can't see inside the cell to study what the proteins are doing. How are we going to study our protein?
We have to be creative and think of ways to see what a protein does without being able to actually see it doing its job. I know this might sound complicated, but luckily scientists in the past have already helped us solve this problem. Remember, proteins are made through the process known as Protein Synthesis. This is the when the cell reads the DNA instructions and makes a protein. Scientists have figured out that you can get rid of a gene and the cell no longer makes that protein.
Remember our genes (instructions in the DNA) provide the directions for which proteins our body should make. Those genes are copied and made into proteins. The process during which the gene is copied into its messenger is called Transcription . Remember, the DNA has to be turned into RNA in order leave the nucleus. DNA can't leave the nucleus because it always has to be protected since it carries our genes. So what if there was no gene to copy? What would happen?
You guessed right! If there was no gene to be copied then no protein would be made. If there was no protein then the cell would mess up. You can tell what the protein was supposed to do by looking at what is missing in the cell. This is one way scientists can answer the question of how to study what proteins do.
But wait! There is another part to protein synthesis. Like you just saw, the mRNA then leaves the nucleus and goes out into the cytoplasm (body of the cell). There, ribosomes read the mRNA and bring in the correct amino acids (building blocks) needed to make the protein. This part of protein synthesis is called Translation. The protein then goes off to do its job in the cell. Scientists have figured out a way to alter this process as well in order to figure out the role of proteins.
Andrew Fire, a famous scientist who won the Nobel Prize in 2006 for his groundbreaking research, decided to try something new in C. Elegans to answer questions about proteins. Originally, he wanted to see if he could make a cell make more protein if he inserted more mRNA. Instead, he found that the protein was not made at all! He took a closer look to see what was happening when he put the new RNA into the cell, and found that the new RNA was interfering with protein synthesis instead of helping make more proteins. Science really is a creative process where scientists try new things to see what works and sometimes they might get surprise results that can often lead them to more interesting discoveries.
This new technique is called RNA Interference. Instead of changing the gene like we talked about earlier, RNA Interference or RNAi manipulates other parts of the process. In RNAi, the messenger RNA is tampered with which makes it so the ribosomes can't read the instructions and no protein can be made. This also allows scientists to answer questions about the role of proteins in the cell just like taking out the gene did.
Click next to see the specifics of how RNA Interference messes with the way proteins are made!