Navigation Links
Clearing jams in copy machinery

Bacteria and humans use a number of tools to direct perhaps the most important function in cells -- the accurate copying of DNA during cell division. New research published this week in Molecular Cell from the laboratory of Rockefeller University's Michael O'Donnell, a Howard Hughes Medical Institute Investigator, now shows that one of these proteins, the beta sliding clamp, serves as a toolbelt from which the correct proteins are retrieved to enable DNA replication in the face of DNA damage.

The replication machinery inside the cell's nucleus is made up of a collection of enzymes including DNA polymerases, sliding clamps and clamp loaders. Bacteria have five known DNA polymerases (higher organisms such as humans have more). As the ring-shaped beta sliding clamp works its way along the DNA double helix, a network of proteins work together to unwind the two strands. Polymerases then add, in assembly line fashion, nucleotide bases -- the building blocks that make up DNA -- to convert the now-single-stranded templates into two new duplex DNA molecules.

The new research shows that two different DNA polymerases, the high fidelity Pol III replicase and the low fidelity Pol IV, coordinate their action to cross obstacles encountered in the replication process. They attach themselves at the same time to one beta sliding clamp. Pol III copies the original DNA, and acts as a proofreader to catch any misspellings and cuts any base that is wrong. But Pol III is a perfectionist, and can stall if it encounters a problem. Pol IV, on the other hand, lays down bases without checking for errors, keeping the process moving even when Pol III gets stuck. The findings by O'Donnell and his colleagues show that, because both polymerases are bound simultaneously to the beta clamp, it can pull either of the polymerases out if its toolbelt as needed.

O'Donnell and his colleagues propose two explanations for how the polymerase switch is controlled.

"One possibili ty is that the beta clamp may sense when Pol III stalls, triggering a change in beta that pulls the polymerase from the primed site, allowing Pol IV to take over synthesis," O'Donnell says. Or, Pol III, upon stalling, may loosen its grip on the template and allow Pol IV to bind the primed site instead.


'"/>

Source:Rockefeller University


Related biology news :

1. Carnegie Mellon scientists develop tool that uses MRI to visualize gene expression in living animals
2. Robot-based system developed at Carnegie Mellon detects life in Chiles Atacama desert
3. Green catalyst destroys pesticides and munitions toxins, finds Carnegie Mellon University
4. Carnegie Mellon University research reveals how cells process large genes
5. Team led by Carnegie Mellon University scientist finds first evidence of a living memory trace
6. Carnegie Mellon scientists create PNA molecule with potential to build nanodevices
7. Carnegie Mellon U. transforms DNA microarrays with standard Internet communications tool
8. Carnegie Mellon develops non-invasive technique to detect transplant rejection at cellular level
9. Carnegie Mellon scientists show brain uses optimal code for sound
10. DNA conclusive yet still controversial, Carnegie Mellon professor says
11. Teens unaware of sexually transmitted diseases until they catch one, Carnegie Mellon study finds
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/31/2016)... March 31, 2016   ... or the "Company") LegacyXChange is excited to ... its soon to be launched online site for trading ... ) will also provide potential shareholders a sense ... technology to an industry that is notorious for fraud. ...
(Date:3/29/2016)... BOCA RATON, Florida , March 29, 2016 /PRNewswire/ ... ("LegacyXChange" or the "Company") LegacyXChange "LEGX" and SelectaDNA/CSI Protect ... Synthetic DNA in ink used in a variety of ... preventing theft. Buyers of originally created collectibles from athletes ... authenticity through forensic analysis of the DNA. ...
(Date:3/22/2016)... India , March 22, 2016 /PRNewswire/ ... market research report "Electronic Sensors Market for Consumer ... Proximity, & Others), Application (Communication & IT, ... Geography - Global Forecast to 2022", published ... industry is expected to reach USD 26.76 ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... Supplyframe, the Industry ... Supplyframe Design Lab . Located in Pasadena, Calif., the Design Lab’s mission ... hardware projects are designed, built and brought to market. , The Design Lab ...
(Date:6/23/2016)... 2016  Blueprint Bio, a company dedicated to identifying, ... community, has closed its Series A funding round, according ... "We have received a commitment from Forentis Fund ... to meet our current goals," stated Matthew Nunez ... to complete validation on the current projects in our ...
(Date:6/23/2016)... ... June 23, 2016 , ... Regulatory Compliance Associates® ... provides a free webinar on Performing Quality Investigations: Getting to Root ... CT at no charge. , Incomplete investigations are still a major concern to ...
(Date:6/22/2016)... 22, 2016 Cell Applications, Inc. and ... to produce up to one billion human induced ... one week. These high-quality, consistent stem cells enable ... and spend more time doing meaningful, relevant research. ... high-volume manufacturing process that produces affordable, reliable HiPSC ...
Breaking Biology Technology: