Scientists have found that a gene named Prox1 is a key player in normal development of a brain structure crucial for learning and memory and remains active throughout life, nurturing the cells vital for making new memories. The study by St. Jude Children's Research Hospital focused on a small region of the hippocampus known as the dentate gyrus, a brain structure needed for memory and learning that is home to the subgranular zone where the neural stem cells destined to become granule cells are housed.
The dentate gyrus is one of two regions of the adult brain where neural stem cells continue to produce the precursor cells that ultimately differentiate into neurons.
Although investigators knew Prox1 was expressed during development of the dentate gyrus, this is the first report detailing the gene's function in this region of the brain. Prox1 is a transcription factor that functions like an on-off switch for genes.
Researchers showed that by removing Prox1 at different stages of mouse development, the dentate gyrus fails to develop properly. Investigators also demonstrated that Prox1 remains important throughout mammalian life to ensure production of new granule cells, which are needed to form new memories.
The findings raise the possibility that subtle mutations in Prox1 might be linked to memory and learning problems, said the paper's senior author Guillermo Oliver, member of the St. Jude Department of Genetics.
"The more we understand about how signaling pathways work in the brain, the more we will eventually be able to manipulate the system to promote or block the differentiation process," he said.