Navigation Links
Human DNA repair process recorded in action
Date:1/29/2009

A key phase in the repair process of damaged human DNA has been observed and visually recorded by a team of researchers at the University of California, Davis. The recordings provide new information about the role played by a protein known as Rad51, which is linked to breast cancer, in this complex and critical process.

The breakthrough comes a decade after Stephen Kowalczykowski, a distinguished professor of microbiology and the study's principal investigator, and Ron Baskin, professor emeritus of molecular and cellular biology, first began developing methods of labeling molecules with fluorescent markers and observing them at work using optical trapping of individual DNA molecules and advanced microscopy techniques. In 2006, the researchers recorded a portion of the bacterial DNA repair process, a system considerably less complex than its human counterpart. The new study was published in the Proceedings of the National Academy of Sciences on Jan. 13.

Human DNA is under constant assault from harmful agents such as ultraviolet sunlight, tobacco smoke and a myriad of chemicals, both natural and man-made. Because damage can lead to cancer, cell death and mutations, an army of proteins and enzymes are mobilized into action whenever it occurs.

Rad51 takes a leading role in the action. Always on call in the cell, molecules of the protein assemble into a long filament along a damaged or broken segment of DNA, where they help stretch out the coiled strands and align them with corresponding segments on the cell's second copy of the chromosome, which serves as a template for reconstruction. Because this protein is regulated by a gene linked to increased risk of breast cancer, BRCA2, it is also thought to play a role in suppression of that disease.

With the ability to watch the assembly of individual filaments of Rad51 in real time, Kowalczykowski's team made a number of discoveries. Among those are that, in contrast to their bacterial counterparts, Rad51 filaments don't grow indefinitely. This indicates that there is an as-yet undiscovered mechanism that regulates the protein's growth, Kowalczykowski said.

Another surprising difference between the human and bacterial processes, Kowalczykowski said, is that Rad51 doesn't fall away from the DNA when repair is complete. Instead, proteins that motor along DNA are required to dislodge it.

"From a practical point of view, being able to record these single molecules gives us insightful information regarding the assembly process," the researcher said. "Now we're able to measure this in a quantifiably meaningful way."

g of individual DNA molecules and advanced microscopy techniques. In 2006, the researchers recorded a portion of the bacterial DNA repair process, a system considerably less complex than its human counterpart. The new study was published in the Proceedings of the National Academy of Sciences on Jan. 13.

Human DNA is under constant assault from harmful agents such as ultraviolet sunlight, tobacco smoke and a myriad of chemicals, both natural and man-made. Because damage can lead to cancer, cell death and mutations, an army of proteins and enzymes are mobilized into action whenever it occurs.

Rad51 takes a leading role in the action. Always on call in the cell, molecules of the protein assemble into a long filament along a damaged or broken segment of DNA, where they help stretch out the coiled strands and align them with corresponding segments on the cell's second copy of the chromosome, which serves as a template for reconstruction. Because this protein is regulated by a gene linked to increased risk of breast cancer, BRCA2, it is also thought to play a role in suppression of that disease.

With the ability to watch the assembly of individual filaments of Rad51 in real time, Kowalczykowski's team made a number of discoveries. Among those are that, in contrast to their bacterial counterparts, Rad51 filaments don't grow indefinitely. This indicates that there is an as-yet undiscovered mechanism that regulates the protein's growth, Kowalczykowski said.

Another surprising difference between the human and bacterial processes, Kowalczykowski said, is that Rad51 doesn't fall away from the DNA when repair is complete. Instead, proteins that motor along DNA are required to dislodge it.

"From a practical point of view, being able to record these single molecules gives us insightful information regarding the assembly process," the researcher said. "Now we're able to measure this in a quantifiably meaningful way."


'/>"/>

Contact: Liese Greensfelder
lgreensfelder@ucdavis.edu
530-752-6101
University of California - Davis
Source:Eurekalert  

Related biology news :

1. Stress disrupts human thinking, but the brain can bounce back
2. New insights into a leading poultry disease and its risks to human health
3. The Evolution of Human Aggression: Feb. 25-27 conference
4. Director of Berman Institute comments on FDA Approval of first human embryonic stem cell trial
5. Researchers genetically link Lou Gehrigs disease in humans to dog disease
6. Researchers examine developing hearts in chickens to find solutions for human heart abnormalities
7. Robo-surgery: As safe and capable as a human assistant in key-hole gallbladder removal
8. Microbot motors fit to swim human arteries
9. Gene switch sites found mainly on shores, not just islands of the human genome
10. JDRF-funded researchers discover proteins regulating human beta cell replication
11. Human beta cells can be easily induced to replicate, according to study in Diabetes
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Human DNA repair process recorded in action
(Date:2/2/2017)... 1, 2017  Central to its deep commitment ... worldwide, The Japan Prize Foundation today announced the ... pushed the envelope in their respective fields of ... scientists are being recognized with the 2017 Japan ... only contribute to the advancement of science and ...
(Date:1/31/2017)... Jan. 31, 2017  Spero Therapeutics, LLC, a ... the treatment of bacterial infections, today announced it ... candidates from Pro Bono Bio Ltd (PBB) to ... multi-drug resistant forms of Gram-negative bacteria.   The assets ... Ltd, a PBB group company. "The ...
(Date:1/26/2017)... , Jan. 26, 2017  Crossmatch, a leading ... a new solution aimed at combatting fraud, waste and ... was introduced at the Action on Disaster Relief conference ... meeting point for UN agencies and foreign assistance organizations ... Fraud, waste and abuse are a largely unacknowledged problem ...
Breaking Biology News(10 mins):
(Date:2/22/2017)... TRIANGLE PARK, N.C., Feb. 22, 2017  United Therapeutics ... its financial results for the fourth quarter and ... 2016 financial results reflect continued growth as net ... million," said Martine Rothblatt, Ph.D., United Therapeutics, Chairman ... our ability to develop and advance our growing ...
(Date:2/21/2017)... /PRNewswire/ - SQI Diagnostics Inc. ("SQI" or the "Company") (TSX-V: SQD; ... three months ended December 31, 2016. SQI ... diagnostics company that develops and commercializes proprietary technologies and products ... ... commercial milestones achieved in fiscal 2016," said Andrew Morris ...
(Date:2/21/2017)... ... 21, 2017 , ... Vortex Biosciences announced the ... benchtop system for collecting intact circulating tumor cells (CTCs) that are shed by ... Tri Conference (Tri-Con) Annual Meeting 2017 (February 19–24 San Francisco). , The ...
(Date:2/21/2017)... ... February 21, 2017 , ... Cancer diagnostics ... has joined its executive team to lead the development and commercialization of its ... help improve the diagnosis and treatment of cancer. The CIDT addresses the need ...
Breaking Biology Technology: