�y��vlog

Most animal cells undergo 'open' mitosis, in which the nuclear envelope -- the two-layered membrane separating the nucleus from the rest of the cell -- breaks down when cell division begins.

However, most fungi use a different form of cell division -- called 'closed' mitosis -- in which the nuclear envelope remains intact throughout the division process.

"We think this research solves the mystery of how DNA double-strand breaks and the nuclear envelope connect for repair in human cells," said Professor Karim Mekhail, co-principal investigator on the study and a professor of laboratory medicine and pathobiology at U of T's Temerty Faculty of Medicine.

In 2015, Mekhail and collaborators showed how motor proteins deep inside the nucleus of yeast cells transport double-strand breaks to 'DNA hospital-like' protein complexes embedded in the nuclear envelope at the edge of the nucleus.

Normal cells use the nuclear envelope tubules to repair DNA, but cancer cells appear to need them more.