Scientists 'map' key brain genes

The map should help research into neurological diseases

US scientists have mapped a key network of gene "switches" in the brain which could aid neurological research.

These gene regulators govern whether parts of the brain develop properly.

The "atlas", created by researchers at the Dana-Farber Cancer Institute in Boston and detailed in Science used mouse brains to pinpoint the genes.

But the map applies to human brains too, and is hoped it will help research into conditions, such as brain tumours, linked to mutations in these genes.

This is the first systematic mapping of all of the major brain areas that shows what regulatory genes are expressed in those specific locations Dr Quifu Ma, Dana-Farber Cancer Institute

Tumours, and other neurological diseases occur because of mutations in these key genes, called transcription factors (TF).

This leads to a chain reaction, with other genes which they control going awry, causing abnormalities in the development or function of nerves and related structures.

Transcription factors direct the formation of neurons and supporting cells called glia from early stage progenitor cells.

Human diseases

To compile the atlas, the investigators looked at mouse genome data.

Mice and human brains share many of the same regulators, which is why the researchers believe their work could help in the understanding of human diseases.

The team singled out all mouse genes that appeared to be transcription factors.

They found more than 1,000 were expressed in the brains of developing mice.

Using genetic probes to investigate thin sections of mouse brains, the scientists found that only 349 of the TF genes were expressed in specific regions, rather than throughout the brain, like the rest.

They concluded these genes controlled the development of the particular areas or structures in which they were uniquely expressed.

It is these 349 which make up the atlas.

The researchers say this is the first time these have been isolated and their locations within different parts of the brain identified.

It should tell scientists which TF genes regulate the development of a particular brain region, and therefore which of them to investigate as possible causes of brain tumours and other diseases.

The team is already examining TF genes regulating nerves involved in pain sensation, certain brain tumours, and speech problems caused by abnormally developing motor neurons that control muscles of the tongue.

Dr Quifu Ma of Dana-Farber's Cancer Biology Department, who led the research, said: "This is the first systematic mapping of all of the major brain areas that shows what regulatory genes are expressed in those specific locations."