Researchers in the US have developed a technique that could allow neurologists to draw a detailed wiring plan of the mammalian brain by inserting genes coding for fluorescent proteins into mice. Dubbed ‘Brainbow’, the system reveals individual neurons within the nervous system in up to 90 different colours.
The work by Jeff Lichtman and colleagues in the Department of Molecular and Cell Biology at Harvard University uses a combination of genes from natural sources such as bioluminescent jellyfish or corals and man-made constructs to produce proteins in four different ‘primary’ colours, red, yellow, cyan and orange. The researchers inserted the genes into the mice genome using the Cre/Lox recombination method developed by Du Pont in the 1980s. This allows tissue specific modification – in this case, the genes are expressed only in the cells of the central nervous system.
One or more gene constructs may be present in a single cell and the entirely random expression of these proteins in the cell cytoplasm creates the many possible colour combinations.
‘In some cells we see a greyish colour because all the proteins are expressed about equally. But in most cells the proteins are at different concentrations giving us a range of hues,’ Lichtman told Chemistry World.
John Bonner
Royal Society of Chemistry
