by Michaela Price
Fun Rating: 4/5
Difficulty Rating: 4/5
What is the general purpose?
Scientists can change an animal’s behavior by using a special protein, colored light, and a technique called optogenetics. The protein will increase or decrease the activity of cells when it is exposed to a specific color of light. Changing the activity of cells can change the animal’s behavior.
Why do we use it?
Optogenetics is often used in neuroscience research to increase or decrease the activity of cells. A scientist can then examine the animals’ behavior to determine if changing cell activity changes the animals’ behavior.
How does it work?
Scientists can determine the function of different types of cells by increasing or decreasing their activity. First, they add a new gene into a group of cells. The gene contains a code that produces a protein through a two-step process: transcription and translation. To increase cell activity, they can introduce a new gene that produces a protein called Channelrhodopsin-2. The Channelrhodopsin-2 protein is naturally produced in algae where it responds to light by increasing the activity of cells that control its flagella (a hair-like structure that allows algae to move). If scientists add the Channelrhodopsin-2 gene to animal cells, they can increase the cells’ activity by exposing the cells to blue light. This technique can be used while an animal completes a task to figure out if a group of cells control a particular behavior. For example, a scientist might turn on a blue light and increase cell activity during a task like wheel running to find out if those active cells can increase the distance the animal runs. A similar process can be used to decrease the activity of cells if scientists introduce a gene that produces a protein called halorhodopsin. Scientists originally found the halorhodopsin protein in a group of organisms that live in extreme environments called halobacteriales, and this protein decreases cell activity when exposed to yellow light.
Testing the function of cells that have the protein Channelrhodopsin-2. (Left) The blue light is off so the cell’s activity is unchanged. A scientist lets the animal run on a wheel and finds out the animal ran a short distance. (Right) Turning on a blue light near cells that have the Channelrhodopsin-2 protein will increase the cell’s activity. If the cells increase running when they are active, the animal will run a longer distance when the blue light is on. Created by author in PowerPoint.
