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

Canadian Discovery Becomes a World-Wide Sensation

Back in 2003, Canadian Paul D. N. Herbert from the University of Guelph’s Zoology department, penned a paper suggesting the creation of a DNA barcode database to identify species taxonomy. The method utilized the mitochondrial gene cytochrome c oxidase I (COI) to serve as the core of a global bioidentification system for animals. Herbert claimed that the COI identification system would provide a reliable, cost-effective and accessible solution to the current problem of species
identification. Its assembly would also generate important new insights into the diversification of life and the rules of molecular evolution.

Fast forward eight years later and the Barcode of Life project now contains genomic information on more than 167,000 species.

Last week, the University of Adelaide hosted the first-ever Southern Hemisphere barcode conference, co-organized by Consortium for the Barcode of Life (CBOL) and co-hosted by several biodiversity institutions and initiatives in Australia. Among other topics, the conference focused on DNA barcoding applications in:

• restaurant ingredients
• medical ingredients
• food chain analysis

For more great information visit www.wired.com.

Biotechnology News

Har Gobind Khorana Dies at 89

Nobel Prize winning biologist who first decoded how a triplet of nucleic acids encoded an amino acid passed away this month.

Har Gobind Khorana, professor emeritus at the Massachusetts Institute of Technology, won the Nobel Prize in 1968 along with Robert Holley and Marshall Nirenberg for discoveries leading to an understanding of how DNA encodes information needed to make proteins. He died earlier this month (November 9) of natural causes.

“He left an amazing trail of technical achievement,” Thomas Sakmar, a professor at Rockefeller University and a former student of Khorana’s told The New York Times.

CLINK: http://the-scientist.com/2011/11/18/har-gobind-khorana-dies-at-89/