A genetic discovery led by scientists at St. Jude Childrens Research Hospital helps answer a long-standing mystery about the eyes of vertebrates, and may translate into a deeper understanding of how genes coordinate the complex process of eye formation and how a rare pediatric eye cancer progresses.
A series of complex developmental processes must be carefully orchestrated for the eye to form correctly, said Michael Dyer, Ph.D., associate member in the St. Jude Department of Developmental Neurobiology. One important aspect of this coordination is that retinal thickness be the same, irrespective of eye size. For example, the mouse eye is about 5,000 times smaller than that of the elephant eye, but the retinal thickness in these two species is comparable.
Working with mice, the researchers found that a gene called N-myc coordinates the growth of the retina and other eye structures to ensure the retina has the proper thickness necessary to convert light from the lens into nerve impulses that the brain transforms into images. Until their study, reported in the Jan. 15 issue of Genes & Development, almost nothing was known about the molecular mechanisms responsible for properly sizing the retina. Dyer is the papers senior author.
This represents the first example of a role for a Myc gene in retinal development, Dyer said. On the basis of our data, we propose that N-myc plays a central role in coordinating retinal proliferation with eye growth during development.
Genes in the Myc family carry out vital roles during prenatal development by regulating the proliferation, size, differentiation and survival of cells. Myc genes are also proto-oncogenesgenes in which a mutation enables them to transform normal cells into cancerous ones. Malfunctioning N-myc genes are often associated with pediatric neural cancers, including neuroblastoma, medulloblastoma and retinoblastoma.
Recently, Dyer and his team identified the specific typ
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St. Jude Children's Research Hospital