LIGHTEN up. Biology is going technicolour. Cells, even whole organisms, can
now be made to glow in almost any colour of the rainbow鈥攊ncluding, for the
first time, bright red and yellow. These spectacular light shows will enable
biologists to observe genes at work by labelling each one with a different
colour.
The new colours are possible thanks to the discovery of six glowing proteins
from brightly coloured corals in reefs off the coasts of Southeast Asia. Genes
for the proteins can be anchored next to the genes researchers want to study in
cells or organisms鈥攚ith different colours assigned to different genes.
When one of the genes is active, the protein linked with it lights up in its
characteristic colour, allowing biologists to track the genes individually.
Until now, scientists who want to watch genes at work have relied mainly on a
marker called the green fluorescent protein (GFP), discovered in Aequorea
victoria,the luminescent jellyfish (New 杏吧原创, 4 March 1995, p
23). Researchers have also made yellow-green and blue variants by mutating the
GFP gene.
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Until now, attempts to find alternatives in other glowing
organisms鈥攕uch as the soft corals known as sea pens鈥攈ave not met
with much success. But now Moscow-based researchers led by Sergey Lukyanov at
the Institute of Bioorganic Chemistry and Yulii Labas of the Institute of
Ecology and Evolution have come to the rescue. They have identified yellow, red,
green and cyan variants of GFP in corals (Nature Biotechnology, vol 17,
p 969).
Labas had a hunch that variants of GFP might exist in brightly coloured
organisms even if they don鈥檛 glow. This was confirmed when he and Lukyanov
identified fluorescent proteins in the corals.
The investigators used reverse versions of the GFP gene鈥攐nes that will
latch on to similar sequences鈥攖o fish out closely related variants of GFP
from coral DNA. The six genes they identified had only 30 per cent of their DNA
in common with the GFP gene鈥攂ut the proteins all had the same barrel-like
structure as GFP.