A labelling revolution
9 Jul 2010 by Evoluted New Media
A new type of fluorescent probe developed by scientists at MIT could transform the labelling of proteins inside cells and replace the currently used techniques.
A new type of fluorescent probe developed by scientists at MIT could transform the labelling of proteins inside cells and replace the currently used techniques.
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Researchers have designed a fluorescent probe that can be targeted to different locations within a cell. Here, the probe is labelling only proteins in the cell membrane. Credit: Katharine White and Tao Uttamapinant | |
A green fluorescent protein known as GFP revolutionised cell biology when it was used to tag and track proteins inside cells. However, GFP is bulky and often interferes with the protein it labels, like actin, which helps give cells their structure and is involved in cell division, motility and communication.
“People use fluorescent proteins to study actin all the time, but fusion to the fluorescent proteins has detrimental effects on actin’s function and trafficking,” said Tao Uttamapinant, co-lead author.
Uttamapinant and colleagues, including graduate student Katharine White and Alice Ting, associate professor of chemistry from MIT developed a new technique, dubbed PRIME – PRobe Incorporation Mediated by Enzymes – which uses a synthetic enzyme to add a blue fluorescent probe to the gene of the protein under study.
The blue fluorescent probe – 7-hydroxycoumarin – is much smaller than GFP and allows actin to move freely throughout the cell and across the nucleus. Researchers must add the gene for the enzyme – known as fluorophore ligase – to each cell at the same time they add the gene for the protein of interest. A short tag is also added to the target protein which allows the enzyme to recognise it.
The researchers also demonstrated that they can label proteins in specific parts of the cell – including the nucleus, cell membrane or cytosol – by tagging the enzyme with genetic sequences that directs it to specific locations. This ensures the enzyme attaches the fluorescent probe only to proteins in this location.
The team is now working on engineering enzymes that will work with other types of probes. Ting has also filed for patent on the technique and plan to commercialise the technology so it can be used in other labs.
