The genes in the developing retina
The potential for collaboration with Dr. McFarlane and other researchers in the field of neuroscience lured AHFMR Senior Scholar Dr. Carol Schuurmans to the University of Calgary in 2001. Her research centres on how neurons acquire their specific identities during development. One aspect of her work involves studying the genes that control the development of cells in the retina.
One of these genes is Zac1, a tumour-suppressing gene that has been studied extensively in cancer biology. Dr. Schuurmans did the experiments that first indicated the role that this gene plays in retinal development. Her team found that it limits the size of the retina in the mouse by means of the processes of programmed cell death and the cessation of cell division. In the absence of the gene, retinal size is not properly controlled, so that the retinas of mice with Zac1 mutations develop more cells than normal; in fact, they have not only extra cells but an extra layer of cells.
"Not a lot is known about how the retina becomes layered during development," says Dr. Schuurmans. "Zac1 could be one of the first factors known that affects the migration of a specific population of retinal cells." Another intriguing finding is a related gene that works in opposition to Zac1, promoting rapid cell division in the retina. Dr. Schuurmans' goal is to further describe the functions of these two genes in the developing retina.
Another of her research projects is done in collaboration with the Stem Cell Network, one of Canada's Networks of Centres of Excellence. Retinal stem cells could prove useful in cell-replacement treatments for degenerative diseases of the retina. Dr. Schuurmans works on identifying the genetic processes that result in turning stem cells into photoreceptors. Her team has already shown experimentally that retinal stem cells can be pushed toward this role. "But our efficiency is currently very low," notes Dr. Schuurmans. She hopes that by turning on various combinations of genes, photoreceptor differentiation can be boosted to levels that can be useful in treatment.