mouse cells, the researchers found that melanopsin could be used to
make neurones light responsive. They found that as well as being
sensitive to blue light, melanopsin uses light at different wavelengths
to regenerate itself. In some forms of hereditary blindness
photoreceptors are lost entirely, but the retinal ganglion cells, the
cells which signal to the brain, remain intact. The researchers believe
that by activating the melanopsin, these cells may gain the ability to
sense and respond to light.
Professor Mark Hankins, from Imperial College London and Charing Cross
Hospital, and one of the papers authors, comments: "It is quite
remarkable that the activation of a single gene can create a functional
photoreceptor. It is an important proof of principle that melanopsin
can make non-light sensitive cells receptive to light, and although not
a cure, could have applications in treating some forms of blindness."
Dr Rob Lucas, from the University of Manchester, and one of the paper's
authors, adds: "The discovery that melanopsin is capable of making
cells photosensitive has given us a unique opportunity to study the
characteristics of this interesting protein. The textbook view of the
eye is that it contains only two light sensing systems, the rods and
cones. However, over the last few years it has become increasingly
accepted that we have a third system, which uses melanopsin, that has
lain undetected during decades of vigorous scientific investigation."
Professor Hankins and Dr Lucas were part of the team who previously
discovered a new light detection system in the eye, totally independent