Solving a longstanding mystery in cell division

The paradox of a cell that shuts down its DNA repair processes during cell division has been solved, according to research published in Science on March 20, 2014. The problem had eluded science for six decades.

“We now know why a crucial DNA-repair process shuts down just when the cell starts to divide into two daughter cells,” says Dr. Daniel Durocher, a Senior Investigator at the Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital in Toronto, Canada.

Throughout most of a cell’s life, corrective mechanisms are nearly always acting to repair DNA strand breaks quickly and accurately. “DNA repair helps thwart cancer and keep the cell in top shape – it is usually all in a day’s work within each cell,” Dr. Durocher adds.

Paradoxically, the exception is at the very moment when chromosomes are most vulnerable, when they physically separate into two cells at cell division (mitosis).

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New link in the DNA repair process of cells

The body’s ability to detect and repair DNA errors that can occur during normal cell processes is essential to healthy human development. A new discovery by researchers at Mount Sinai’s Samuel Lunenfeld Research Institute released today in the prestigious journal Nature, uncovers a previously unknown link in the DNA repair process, offering a deeper understanding of how DNA repair mechanisms fail in diseases like cancer.

Senior Investigator Dr. Daniel Durocher and his team of researchers at the Lunenfeld, including lead author Dr. Amelie Fradet-Turcotte, have discovered the function of a protein that is vital to the efficient repair of DNA damage. This protein, called 53BP1, responds to a unique ‘flare’ signal called ubiquitin (another protein involved in cellular regulation), when there is DNA damage present and then works together to accelerate the repair process.

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The Dark Side of the Double Helix

Can you find the Bio-Rad product at 15:33? (hint: it is quite ancient!)

Around the Nucleus

Blame it on the DNA