[ RadSafe ] Couple articles on DNA repair

[Cary Renquist]

One on signaling damage and one on damage repair.

Cary



Mobilizing the Repair Squad: Critical Protein Helps Mend Damaged DNA
http://bit.ly/71LJ0K

ScienceDaily (Dec. 30, 2009) - In order to preserve our DNA, cells have developed an intricate system for monitoring and repairing DNA damage. Yet precisely how the initial damage signal is converted into a repair response remains unclear. Researchers at the Salk Institute for Biological Studies have now solved a crucial piece of the complex puzzle.

In a forthcoming article in the Dec. 24 issue of Molecular Cell, they show that a protein named CtIP plays an essential role in the DNA damage "signal-to-repair" conversion process. "Being able to repair damaged DNA is extremely important; the cell has to know when it has received this type of damage and respond appropriately," explains Tony Hunter, Ph.D., American Cancer Society Professor in the Molecular and Cell Biology Laboratory and director of the Salk Institute Cancer Center, who led the study. "Failure to do so can have disastrous consequences."
 
 Journal article abstract:
   Molecular Cell - CtIP Links DNA Double-Strand Break Sensing to Resection 
     http://bit.ly/5VlnuO



Understanding DNA Repair And Cancer
http://bit.ly/7H5hre

Article Date: 05 Dec 2009 - 0:00 PST
A protein that plays a key role in copying DNA also plays a vital role in repairing breaks in it, UC Davis scientists have found. The work is helping researchers understand how cancer cells can resist radiation and chemotherapy, as well as how cells become cancerous in the first place.

The protein, known as proliferating cell nuclear antigen, forms a ring that fits around the DNA double helix. This cuff-like ring helps to keep in place DNA polymerase, the enzyme that makes a copy of the DNA strand when cells divide into two new cells.

The new study, published Nov. 25 in the journal Molecular Cell, shows that PCNA performs a similar function during DNA recombination -- when pairs of chromosomes line up and exchange strands of DNA. Recombination occurs when cells divide to form eggs and sperm, and also when cells try to repair breaks that cross both strands of DNA.

"This is a new trick from an old horse," said Wolf-Dietrich Heyer, professor of microbiology at UC Davis and leader of the molecular oncology program at the UC Davis Cancer Center.

 Journal article abstract:
   Molecular Cell - PCNA Is Required for Initiation of Recombination-Associated DNA Synthesis by DNA Polymerase δ 
     http://bit.ly/5A9zTb