New tech uses light to turn genes on and off

Scientists have developed a new technique that can rapidly turn genes on and off, simply by shining light on the cells.
The technology can help researchers better understand the functions and role of individual genes.
Although human cells have an estimated 20,000 genes, only a fraction of those are turned on at any given time, depending on the cell's needs - which can change by the minute or hour.
To find out what those genes are doing, researchers need tools that can manipulate their status on similarly short timescales.
The new technology developed at Massachusetts Institute of Technology (MIT) and the Broad Institute can rapidly start or halt the expression of any gene of interest simply by shining light on the cells.

The work is based on a technique known as optogenetics, which uses proteins that change their function in response to light.

In this case, the researchers adapted the light-sensitive proteins to either stimulate or suppress the expression of a specific target gene almost immediately after the light comes on.
"Cells have very dynamic gene expression happening on a fairly short timescale, but so far the methods that are used to perturb gene expression don't even get close to those dynamics," said Silvana Konermann, an MIT graduate student in brain and cognitive sciences.
"To understand the functional impact of those gene-expression changes better, we have to be able to match the naturally occurring dynamics as closely as possible," Konermann said.

The ability to precisely control the timing and duration of gene expression should make it much easier to figure out the roles of particular genes, especially those involved in learning and memory.
The new system can also be used to study epigenetic modifications - chemical alterations of the proteins that surround DNA - which are also believed to play an important role in learning and memory.
Konermann and Mark Brigham, a graduate student at Harvard University, are the lead authors of a paper describing the technique in the journal Nature.