A new study provides a mechanistic explanation of how ribonucleotides embedded in genomic DNA are recognized and removed from cells. Two mechanisms, enzymes called ribonucleases (RNases) H and the DNA mismatch repair system, appear to interplay to root out the RNA components.
Storici and Georgia Tech biology graduate students Ying Shen and Kyung Duk Koh conducted the study in collaboration with Bernard Weiss, a professor emeritus in the Department of Pathology and Laboratory Medicine at Emory University.
"We wanted to understand how cells of the bacterium Escherichia coli and the yeast Saccharomyces cerevisiae tolerate the presence of different ribonucleotides embedded in their genomic DNA. We found that the structure of a ribonucleotide tract embedded in DNA influenced its ability to cause genetic mutations more than the tract's length," said Storici.
With double-stranded DNA, when wrong bases are paired or one or few nucleotides are in excess or missing on one of the strands, a mismatch is generated. If mismatches are not corrected, they can lead to mutations.
The researchers found that single mismatched ribonucleotides in chromosomal DNA were removed by either the mismatch repair system or RNase H type 2. Mismatched ribonucleotides in the middle of at least four other ribonucleotides required RNase H type 1 for removal.
Defects in the mismatch repair system are known to predispose a person to certain types of cancer. Because the mismatch repair system is conserved from unicellular to multicellular organisms, such as humans, this study's findings open up the possibility that defects in the mismatch repair system could have consequences more critical than previously thought given the newly identified function of mismatch repair to target RNA/DNA mispairs.
The results also provide new information on the capacity of RNA to play an active role in DNA editing and remodeling, which could be the basis of an unexplored process of RNA-driven DNA evolution.
This project was supported by the National Science Foundation (NSF) (Award No. MCB-1021763). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of the NSF.
Abby Robinson | EurekAlert!
More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
19.01.2018 | Materials Sciences
19.01.2018 | Health and Medicine
19.01.2018 | Physics and Astronomy