Newborn mouse neurons break and repair DNA during brain development

Newborn neurons in mice break both strands of their DNA as they move through narrow spaces in developing brain tissue, researchers reported June 17 in Nature. The breaks are repaired once the neurons reach their final positions, usually within a day.

The process appears in regions of the genome that are not essential for cell survival. Researchers found that this allows most neurons to complete migration and continue normal growth.

Repair speed and location of damage The repair occurs rapidly enough that no mutations or lasting damage were detected in the experiments. Removing a key DNA repair protein called ligase IV left unrepaired breaks in movement-related brain areas. Mice lacking the protein later showed motor skill difficulties.

The findings indicate that incomplete repair during this stage can produce long-term functional changes.

Possible links to human conditions The same mechanism may operate during human brain development, where neurons travel longer distances. Researchers noted that certain antibiotics given to premature infants could interfere with the repair process. Further study is required to determine whether unrepaired breaks contribute to neurological conditions or pediatric brain tumors in humans.