Gene decoding obeys road traffic rules

July 31, 2013, Weizmann Institute of Science

One of life's most basic processes—transcription of the genetic code—resembles road traffic, including traffic jams, accidents and a police force that controls the flow of vehicles. This surprising finding, reported recently by Weizmann Institute researchers in Nature Communications, might facilitate the development of a new generation of drugs for a variety of disorders.

Transcription indeed involves a step resembling the motion of a vehicle: Enzymes "ride" along gene "tracks," creating molecules that will later be translated into the various proteins involved in the life of the cell. In the new study, a research team headed by Prof. Rivka Dikstein of the Biological Chemistry Department has found that just as on the road, maintaining a reasonable distance between the vehicles—that is, the transcribing enzymes—is the surest way to reach a destination safely. In addition to Dikstein, the team included Dr. Nadav Marbach-Bar, Amitai Ben-Noon, Shaked Ashkenazi, Ana Tamarkin-Ben Harush, Dr. Tali Avnit-Sagi and Prof. Michael Walker.

The scientists tracked the transcription of genes coding for tiny regulatory molecules called microRNAs. Working with , they experimented with different rates of transcription: a high rate, in which the enzymes are launched in bursts, and a low one, in which the enzymes are launched individually, at greater intervals. The experiments yielded a paradoxical finding: When the transcription enzymes were launched in bursts, the amount of the resultant microRNA dropped; conversely, when the enzymes were launched at greater intervals, production of microRNA was more efficient.

It turned out that when the enzymes were launched in bursts, one rapidly following the next, they ended up in a traffic jam: When the first paused at a "road bump"—a molecular signal that creates a pause in transcription—the enzymes that followed crashed into it, falling off the gene. Naturally, such "traffic accidents" reduced the amount of resultant microRNA. In contrast, when the enzymes were launched one by one, they maintained a safe distance: Each had sufficient time to slow down at the "bump" and to succeed at creating a microRNA molecule. In other words, the lower rate of release of individual enzymes proved to be a more efficient method for creating microRNAs.

Because these findings shed new light on the manufacture of microRNAs, they might help in the design of drugs based on these molecules. Discovered as recently as in the 1990s, microRNAs hold great promise for serving as future therapeutics because they can help control gene expression—for example, blocking the activity of cancer-causing genes. This ability is particularly valuable when a molecular process needs to be manipulated at the deepest possible level, inside the cell nucleus.

In a more fundamental sense, the new study helps reveal how transcription is regulated. For example, the study has shown that in inflammation, when the body is threatened with invasion by a virus or bacterium, the release of anti-inflammatory microRNAs is temporarily suspended. The suspension occurs because inflammation increases the launch rate of transcription enzymes, creating that reduce the production of the microRNA. This reduction, in turn, "buys time" for the inflammation, giving it a chance to perform its healing function before it is terminated by the microRNA.

Finally, this study helps explain an earlier finding in Dikstein's lab: In longer genes, transcription enzymes tend to be launched at a low rate, that is, at great intervals. The longer the gene, the greater the risk that it has molecular "bumps" that can create traffic jams, derailing transcription. Therefore, transcription enzymes riding along such genes at a lower rate can do their job more efficiently than the enzymes launched in rapid bursts.

Explore further: Team finds markers related to ovarian cancer survival and recurrence

Related Stories

Team finds markers related to ovarian cancer survival and recurrence

April 30, 2013
(Medical Xpress)—Researchers at the University of Illinois have identified biomarkers that can be used to determine ovarian cancer survival and recurrence, and have shown how these biomarkers interact with each other to ...

IRCM researchers fuel an important debate in the field of molecular biology

January 26, 2012
Dr. Francois Robert, molecular biology researcher at the Institut de recherches cliniques de Montréal (IRCM), and his team confirmed that the phosphorylation of RNA polymerase II, a key enzyme in the process of gene ...

Recommended for you

Peers' genes may help friends stay in school, new study finds

January 18, 2018
While there's scientific evidence to suggest that your genes have something to do with how far you'll go in school, new research by a team from Stanford and elsewhere says the DNA of your classmates also plays a role.

A centuries-old math equation used to solve a modern-day genetics challenge

January 18, 2018
Researchers developed a new mathematical tool to validate and improve methods used by medical professionals to interpret results from clinical genetic tests. The work was published this month in Genetics in Medicine.

Can mice really mirror humans when it comes to cancer?

January 18, 2018
A new Michigan State University study is helping to answer a pressing question among scientists of just how close mice are to people when it comes to researching cancer.

Epigenetics study helps focus search for autism risk factors

January 16, 2018
Scientists have long tried to pin down the causes of autism spectrum disorder. Recent studies have expanded the search for genetic links from identifying genes toward epigenetics, the study of factors that control gene expression ...

Group recreates DNA of man who died in 1827 despite having no body to work with

January 16, 2018
An international team of researchers led by a group with deCODE Genetics, a biopharmaceutical company in Iceland, has partly recreated the DNA of a man who died in 1827, despite having no body to take tissue samples from. ...

The surprising role of gene architecture in cell fate decisions

January 16, 2018
Scientists read the code of life—the genome—as a sequence of letters, but now researchers have also started exploring its three-dimensional organisation. In a paper published in Nature Genetics, an interdisciplinary research ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.