Scientists have developed a new method that allows them to simultaneously label and track multiple proteins in living cells. The technique, called multiplex CRISPR imaging (muCRISPRi), uses a combination of CRISPR-Cas9 gene editing and fluorescent labeling to visualize specific proteins in real time.

The new method could provide new insights into the complex interactions between proteins and how they contribute to cellular processes. It could also be used to study the effects of drugs and other compounds on protein function.

"This new method will allow us to see how proteins work together in living cells in a way that has never been possible before," said study leader Dr. Jonathan Weissman, a professor of cellular and molecular pharmacology at the University of California, San Francisco.

The muCRISPRi technique works by combining two different CRISPR-Cas9 systems. One system is used to edit the DNA of cells so that they express fluorescent proteins when certain genes are activated. The other system is used to control which genes are activated by targeting specific DNA sequences.

By combining these two systems, researchers can create a library of cells that each express a different fluorescent protein when a specific gene is activated. This allows them to track the expression of multiple genes simultaneously and see how they interact with each other.

The researchers used muCRISPRi to label and track 10 different proteins in living cells. They were able to see how the proteins interacted with each other and how they responded to different stimuli.

For example, the researchers used muCRISPRi to study how proteins involved in the immune response interact with each other. They found that these proteins form clusters that move around the cell and interact with each other to mount an immune response.

The researchers also used muCRISPRi to study how proteins involved in cell division interact with each other. They found that these proteins form a complex network that controls the timing and accuracy of cell division.

The muCRISPRi technique could be used to study a wide variety of cellular processes, from protein folding to signal transduction. It could also be used to develop new drugs and therapies by identifying proteins that are involved in disease processes.

"The potential applications of this new technology are enormous," said Weissman. "We are excited to see how other scientists use muCRISPRi to make new discoveries about how cells work."