April 1, 1996
Researchers find major gene for eye development
TORONTO - A team of researchers led by Dr. Roderick McInnes of the departments of Genetics and Paediatrics at The Hospital for Sick Children, Dr. Margit Burmeister at the University of Michigan, and Dr. Mark Hankin at the Medical College of Ohio, has identified a major regulatory gene -called Chx10 - that is a critical control of retina and eye development in mammals. The work was done in collaboration with Ben Taylor and Tom Roderick at the Jackson Laboratories in Bar Harbor, Maine. Their research is reported in the April issue of Nature Genetics.
While Chx10 was discovered by the McInnes lab several years ago, it is only the current work which has demonstrated that Chx10 is essential for the development of a normal eye.
Mice lacking a properly functioning Chx10 gene have profoundly abnormal eyes with several retinal abnormalities that make them blind. Their eyes are much smaller than normal, and the number of cells in the retina is reduced because of impaired multiplication of cells that give rise to the retina. The researchers also found that one of the seven major retinal cell types -bipolar cells - are either missing or incompletely formed in the retina of the mice without a functional Chx10 gene. This finding suggests that the Chx10 gene is particularly important for making this type of retinal cell.
Recent research has indicated that the network of genes required to form an eye may be very similar in species ranging from flies to mammals. It is thus likely that the Chx10 gene will be essential for normal eye development in many species, including humans. As a result, a search for defects in Chx10 is underway in humans with certain eye defects, such as microphthalmia (small eye).
The discovery of genes which control retinal development might have long-term implications for the treatment of conditions that cause destruction of the retina in humans. If ways could be found to manipulate the activity of regulatory eye genes such as Chx10, it may someday be possible to induce the retina to regenerate in patients with these abnormalities.
Dr. McInnes is a professor of Paediatrics and of Molecular and Medical Genetics at the University of Toronto. The Hospital for Sick Children is a health care, teaching and research centre dedicated exclusively to children, affiliated with the University of Toronto.
Support for Dr. McInnes' research was provided by the Canadian Genetic Diseases Network, the Medical Research Council of Canada, and the Retinitis Pigmentosa Eye Research Foundation of Canada.
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