The St. Jude team showed that Rb limits the proliferation of immature retinal cells so the retina develops to a normal size. The Rb protein also prompts specific cells to develop into light-sensitive cells called rods.
The study results also offer clues to solving a long-standing paradox, according to Michael A. Dyer, Ph.D., an assistant member of the Department of Neurobiology and senior author of the Nature Genetics article.
"Children who lack the gene for Rb are at high risk for developing retinoblastoma, yet mice that also lack the Rb gene do not develop the disease," Dyer said. "The first step to solving that paradox and understanding why mice without the Rb protein don't get retinoblastoma is figuring out what that protein does during normal mouse development. Our study was that first step. What we're learning could eventually help us to block the molecular signals that trigger retinoblastoma in children."
Understanding the development of tissues and organs can also help researchers understand why certain types of pediatric tumors occur. The study provides strong evidence that retinoblastoma is a developmental tumor, caused by a genetic abnormality in a tissue or organ present in the developing embryo. Following birth, this abnormality triggers cancer in that tissue or organ during infancy or childhood.
The St. Jude study also broke new ground in the study of retinal development by overcoming a major obstacle blocking earlier researchers from studying the role
Contact: Bonnie Cameron
St. Jude Children's Research Hospital