Protein can nurture or devastate brain cells, depending on its 'friends,' resear...(ngineering to create mice in which they ...),Health

Dr. Eisch found that when Cdk5 is removed from immature nerve stem cells, normal cell division occurs, but the nerve cells never reach maturity. Researchers also removed Cdk5 from neighboring mature nerve cells and discovered that this removal resulted in the production of fewer immature nerve cells.

"The techniques we used have moved us several steps beyond what is usually done in the field," Dr. Eisch said. "We're beginning to assemble a dictionary of what regulates neurogenesis. By understanding what's vital at each stage of development, we hopefully can one day manipulate human nerve cells so that the brain can withstand neurodegenerative diseases such as Alzheimer's."

Dr. Bibb studied the "Mr. Hyde" component of Cdk5. Using a different but equally advanced set of genetic approaches, his team studied the effects of turning Cdk5 to the "dark side" by expressing a shortened form of the Cdk5 activating partner called p25. The group found that when paired with p25 in deep brain structures, Cdk5 had destructive effects on motor coordination and learning in the mice.

Neuropsychiatric illnesses such as schizophrenia, attention deficit hyperactivity disorder and drug addiction involve similar brain pathways as the ones studied and implicated in the "Mr. Hyde" aspect of Cdk5, Dr. Bibb said.

Dr. Bibb also used new technology to reach deeper inside the brain and explore regions beyond those typically examined in conjunction with neurodegenerative diseases. His team used a green fluorescent protein to trace Cdk5's activity in mice, allowing the researchers to examine precisely what was happening in the brain when the Cdk5/p25 pairing was overexpressed.

They found that the overexpression damaged circuitry in the area of the brain that controls movement and reward-based learning. T
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