Prox1 gene linked to memory

A gene called Prox1 has a crucial role in an area of the brain involved in creating new memories, US scientists have discovered. The researchers focused on a region of the brain called the dentate gyrus, a small structure which is important for learning, memory and spatial navigation.

Dr Alfonso Lavado and colleagues from St Jude Children's Research Hospital in Memphis, Tennessee, demonstrated that Prox1 is needed for the maturation of neurons (nerve cells) in the dentate gyrus during embryo development. The dentate gyrus is one of the few regions in the adult brain where the birth of new neurons from stem cells occurs. This high rate of 'neurogenesis' is believed to contribute to the formation of new memories.

Inactivating Prox1 during mouse development resulted in the mice missing immature 'progenitor' cells needed for adult neurogenesis to happen. These progenitor cells, which are found in the middle layer of the dentate gyrus, were also found to be responsible for maintaining the supply of stem cells in this area.

Although Prox1 was already known to be activated in the dentate gyrus during brain development and adult neurogenesis, the new research is the first detailed description of its function. This area of the brain is also thought to play a role in modulating the symptoms of stress and depression.

Dr Guillermo Oliver, senior author of the study, explained that the findings raise the possibility that mutations in the Prox1 gene may be related to learning and memory problems. 'The more we understand about how signalling 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. The findings were published online in the journal PloS Biology.