Powerful protein halts DNA damage and may block tumors

TopBP1: Remember that somewhat unwieldy name. It refers to a protein researchers at St. Jude Children's Research Hospital believe prevents DNA damage early in the formation of a brain. What's more, they think it could suppress tumor development.

The effort, led by Peter McKinnon, the paper's senior author and a member of St. Jude's Department of Genetics, tracked what happens when TopBP1 was selectively shut down in mice, at different stages of the development of their brains. They found the loss of the protein hurt the brain the worst when removed in early progenitor cells, which subdivide and develop cells that control cortex functions such as memory, vision and movement. If clinicians waited a few days before disabling the TopBP1 protein, the brain and nervous system development-related progenitor cells developed less drastic defects.

Subsequently, they found that low-dose radiation was more likely to lead to cell "suicide" in the earlier progenitor cells, with the DNA strand more sensitive to breaks. In short, they determined that TopBP1's mission in the body is to monitor DNA damage, and then step in when that damage takes place during cell replication. This refutes an earlier belief that TopBP1 was responsible for DNA replication and cell growth and development.

This is in early stages. And we all know the risks of it not being replicated in future trials. But McKinnon and the others plan to explore their finding further with additional studies.

"When we selectively knocked out TopBP1 in mice, the amount of DNA damage we saw suggests that TopBP1 is likely to be a tumor suppressor," McKinnon said in a statement. "We are exploring that question now." Further details are in the journal Nature Neuroscience.

- here's the release
- read the journal abstract