Harvard Health Letter

In Brief: RNA interference: Silencing of the genes

In Brief

RNA interference: Silencing of the genes

The Human Genome Project identified all human genes, but it didn't tell us what each of these genes do or how to turn them on and off. The 2006 Nobel Prize in Physiology or Medicine was awarded to Andrew Fire and Craig Mello for their studies of a powerful technology called RNA interference — RNAi for short — that is helping scientists do just that, and it may provide doctors with a way to switch off the genes that cause disease.

Every cell in your body has the same set of genes. Yet a cell, say, in your stomach that's churning out acid acts — and looks — nothing like a cell in your eye that reacts to light. The reason that genetically identical cells can be so different from one another is the variability in the genes that are "turned on" and active. Every active gene makes a protein. Scientists have discovered that cells make very short strands of RNA, called microRNAs, which can stop the ability of a particular gene to make a particular protein — effectively "silencing" the gene. The field of RNA interference was born.

Considered just a curiosity at first, RNAi has revolutionized biological research. Suppose you wanted to know which exact genes caused a stomach cell to make acid. One way of doing so would be to silence one gene after another, and see when the cell stops making acid. All over the world, scientists are using RNAi to systematically shush genes and observe the results.

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