Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dual Discoveries in Genetic Processing Improve Accuracy of Genome Information

11.08.2003


University of Connecticut Health Center geneticists have made a two-fold discovery in gene recoding that will significantly increase understanding of the information in genome sequences and could prove to be a knowledge expressway scientists need for unraveling nervous system disorders such as Parkinson Disease and epilepsy.

The research, published in the Aug. 8 issue of the journal Science, was supported by the National Science Foundation (NSF), the independent federal agency that supports fundamental research and education across all fields of science and engineering.

Geneticist Robert Reenan and fellow researchers used comparative genomics to discover a telltale signature of genes that are recoded as DNA is converted to RNA during the protein-making process. There, an enzyme converts adenosine to the nucleoside inosine by a process called "A-to-I" RNA editing. The scientists subsequently found that such recoding is largely confined to the nervous system across species and pinpointed a target of the process in humans.

"The proteins targeted by editing are basically the machinery that allow nervous systems to function on a timescale of milliseconds, which is not a demand placed on every organ," said Reenan.

The phylogenetic signatures are identical sequences of genetic coding found in each species studied, serving as markers corresponding to specific genes targeted for A-to-I RNA editing. The identical presence in both species suggests that the editing site arose some time ago evolutionarily and has been retained in these species -- and likely others -- because it provides a broadly useful selective advantage for survival.

Recoding, or "RNA editing," and the entire process are much like photocopying a recipe from a cookbook and writing changes on the photocopy rather than on the book’s pages. The revisions on the copy would then be used to prepare the food, but the original recipe in the book would remain unchanged.

For cells to manufacture protein, they must first copy the segment of the gene’s DNA that holds the blueprint or Scoding" for the protein. This copy, which consists of a single strand of RNA, is called messenger RNA, or "mRNA." Converting the DNA into the mRNA instructions that code for the manufacture of protein from amino acids is called "transcription." The working mRNA copy is sometimes modified, or "recoded," as it is formed. It is unknown how many RNA transcripts for genes are recoded in the human genome because this process occurs on the copies rather than the original.

For more than a decade, sites where A-to-I RNA editing had occurred were discovered largely by chance. "The one thing that becomes clear about the RNA editing sites is that they’re all different; there (was) no way to predict where an RNA editing site would occur from genome sequence," said Reenan. "We hoped to get clues about RNA editing by comparing genomes of different species."

Clues came as the researchers compared more than 900 genes between two species of the fruit fly Drosophila. They found a signature in genomic DNA in genes shared between species where RNA transcription products are destined to be edited by the enzyme adenosine deaminase. "The signature we found was an unexpectedly high level of DNA sequence identity between species," said Reenan. The signature reliably identifies genes that are recoded during transcription, providing scientists with a means to predict the occurrence of editing.

"Being able to predict editing sites is a revolutionary discovery that will greatly increase the value of existing genome sequences," said Molecular Biologist Joanne Tornow, a program director with the NSF’s Division of Molecular and Cellular Biosciences. "Dr. Reenan’s use of comparative genomics to make this very significant finding underscores the importance of investing in the sequencing of a wide variety of organisms." Reenan and his colleagues then applied their newfound knowledge to a wide range of human, mouse and rat genes. They found the process also targets a gene in the human brain already known to foster an inherited form of epilepsy.

So far, the researchers have noticed A-to-I RNA editing in only nervous systems and specifically in genes encoding proteins necessary for sending fast electrical and chemical signals. They examined many genes not directly involved in nervous system function.

"The literal genome is not the final word and, for whatever reason, this mechanism (A-to-I editing) is almost exclusive to the nervous system," Reenan said.

With the knowledge of the signature and that A-to-I RNA editing occurs primarily in nervous systems, scientists can now more closely examine how recoding affects expression by nervous systemspecific genes, including those responsible for epilepsy and Parkinson Disease.



Principal Investigator: Robert Reenan, (+1-860) 679-3691, rreenan@neuron.uchc.edu

Manny Van Pelt | National Science Foundation
Further information:
http://www.nsf.gov

More articles from Life Sciences:

nachricht Topologische Quantenchemie
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

nachricht Topological Quantum Chemistry
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Ultrathin device harvests electricity from human motion

24.07.2017 | Power and Electrical Engineering

Scientists announce the quest for high-index materials

24.07.2017 | Materials Sciences

ADIR Project: Lasers Recover Valuable Materials

24.07.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>