Rewrite the textbooks: Transcription is bidirectional

January 25, 2009

Genes that contain instructions for making proteins make up less than 2% of the human genome. Yet, for unknown reasons, most of our genome is transcribed into RNA. The same is true for many other organisms that are easier to study than humans.

Researchers in the groups of Lars Steinmetz at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, and Wolfgang Huber at the European Bioinformatics Institute (EMBL-EBI) in Hinxton, UK, have now unravelled how yeast generates its transcripts and have come a step closer to understanding their function.

The study, published online in Nature, redefines the concept of promoters (the start sites of transcription) contradicting the established notion that they support transcription in one direction only. The results are also representative of transcription in humans.

Investigating all transcripts produced in a yeast cell, the scientists found that most regions of the yeast genome produce several transcripts starting at the same promoter. These transcripts are interleaved and overlapping on the DNA. In contrast to what was previously thought, the vast majority of promoters seem to initiate transcription in both directions.

Not all of the produced transcripts are stable, many are degraded rapidly making it difficult to observe what they do. While some of the RNA molecules might be 'transcriptional noise' without function, other transcripts control the expression of genes and production of proteins. The act of transcription itself is also likely to play an important role in regulation of gene expression. Transcribing one stretch of DNA might either help or in other cases interfere with the transcription of a gene close by. Moreover, transcripts without a current purpose can serve as 'raw material for evolution' and acquire new functions over time.

The results shed light on the complex organisation of the yeast genome and the insights gained extend to transcription in humans. A better understanding of transcription mechanisms could find application in new technologies to tune gene regulation in the future.

Source: European Molecular Biology Laboratory

Explore further: Chemists and applied physicists observe RNA polymerase at work in real time

Related Stories

A novel toxin for M. tuberculosis

August 4, 2015

Despite 132 years of study, no toxin had ever been found for the deadly pathogen Mycobacterium tuberculosis, which infects 9 million people a year and kills more than 1 million.

Cell aging slowed by putting brakes on noisy transcription

July 30, 2015

Working with yeast and worms, researchers found that incorrect gene expression is a hallmark of aged cells and that reducing such "noise" extends lifespan in these organisms. The team published their findings this month in ...

Recommended for you

How much for that Nobel prize in the window?

October 3, 2015

No need to make peace in the Middle East, resolve one of science's great mysteries or pen a masterpiece: the easiest way to get yourself a Nobel prize may be to buy one.

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Drone market to hit $10 billion by 2024: experts

October 3, 2015

The market for military drones is expected to almost double by 2024 to beyond $10 billion (8.9 billion euros), according to a report published Friday by specialist defence publication IHS Jane's Intelligence Review.

Fusion reactors 'economically viable' say experts

October 2, 2015

Fusion reactors could become an economically viable means of generating electricity within a few decades, and policy makers should start planning to build them as a replacement for conventional nuclear power stations, according ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Jan 26, 2009
This is absolutely fascinating. It points, in one way, to genetic evolution being a kind of Heath-Robinson serendipity. In another way though it points to why multicellular life took thousands of millions of years to evolve, and to the amazing robustness of genomes which endure.

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.