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Fluorescent tags for live cells
MADISON, Wis.—In a deal that seeks to get the most out of Leica's TCS STED (stimulated emission depletion) superresolution microscope, Promega Corp. scientists will develop fluorescent ligands for its HaloTag fusion proteins, that will be used to label proteins for visualization within live cells. According to Promega, these developments overcome the shortcomings of other fluorescent proteins for live cells, while also outstripping labeling technologies that only work for fixed cells.
"The power of the microscopy presents some problems for other technologies," notes Dr. Georgyi Los, Ph.D., senior scientist and group leader of imaging technologies for Promega. "GSP tagging doesn't have the proper properties for visualization, and other fluorescent labels only work on fixed cells. With HaloTag, we can attach them to the surface of live cells and get more than just the snapshot view you get using fixed cells."
In addition, using the STED microscope researchers are able to visualize protein clusters smaller than 100 nm, a leap that opens a host of potential new discoveries of important proteins.
"We know that there are many protein complexes that are smaller than this," Los notes. "Being able to visualize these means we can begin to study these smaller protein clusters."
Leica's TCS STED, was brought to market last year and is the commercialization of the work of Dr. Stefan Hell of the Max-Planck Institute in Germany. While Leica has an ongoing relationship with Hell's lab at Max-Planck, Promega has also recently begun working with the renowned researcher as it looks to find ways to further adapt its HaloTag technology, not only to the current LCS STED, but also to gain insights of the ongoing work Hell is conducting to develop next-generation STED technology.
"We have only been working together for a couple of months, but this is a good opportunity for us to work with prototypes and next-generation technology," says Los.
For Promega, the deal with Leica is the latest iteration of work the company has been conducting the last couple of years, all revolving around developing new ways to lable proteins using HaloTag.
Work is ongoing, Los notes, as currently HaloTag can attach to membrane proteins of live cells, but has not yet been perfected for imaging within the cells. While this presents special problems in terms of preserving the cell's internal environment, Los believes it is a hurdle he and his team can overcome.
"I'm optimistic we will accomplish this," he says. "We can't say when, but we will get there." DDN