Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


In a first, Einstein scientists discover the dynamics of transcription in living mammalian cells

Transcription — the transfer of DNA’s genetic information through the synthesis of complementary molecules of messenger RNA — forms the basis of all cellular activities.

Yet little is known about the dynamics of the process — how efficient it is or how long it takes. Now, researchers at the Albert Einstein College of Medicine of Yeshiva University have measured the stages of transcription in real time. Their unexpected and surprising findings have fundamentally changed the way transcription is understood.

The researchers used pioneering microscopy techniques developed by Dr. Robert Singer, co-chair of anatomy & structural biology at Einstein and senior author of the study, which appears in the August issue of Nature Structural & Molecular Biology.

The study focused on RNA polymerase II--the enzyme responsible for transcription. During transcription, growing numbers of RNA polymerase II molecules assemble on DNA and then synthesize RNA by sequentially recruiting complementary RNA nucleotides.

... more about:
»Polymerase »RNA »elongation »enzyme »transcription

To visualize the transcription process, the researchers used living mammalian cells, each of which contained 200 copies of an artificial gene that they had inserted into one of the cell’s chromosomes. Then, by attaching fluorescent tags to RNA polymerase II, they were able to closely monitor all three phases of the transcription process: binding of the enzyme molecules to DNA, initiation (when the enzyme links the first few RNA nucleotides together) and elongation (construction of the rest of the RNA molecule). As they observed the RNA polymerase II molecules attaching to DNA and making new RNA, they saw many cases where enzyme molecules attached — and then promptly fell off.

“One surprising finding was how inefficient the transcription process really is, particularly during its first two stages,” says Dr. Singer. “It turns out that only one percent of polymerases that bind to the gene actually remain on to help in synthesizing an RNA molecule. Transcription is probably inefficient for a reason. We’re not sure why, but it may be because all the factors needed for transcription have to come together at the right time and the right place, so there’s a lot of falling off and adding on of polymerases until everything is precisely coordinated.”

The researchers observed that the binding phase of transcription lasted six seconds and initiation lasted 54 seconds. By contrast, the final stage of transcription — elongation of the RNA molecule — took a lengthy 517 seconds (about eight minutes). The possible reason: The “lead” polymerase on the growing polymerase II enzyme sometimes “paused” for long periods, retarding transcription in the same way that a Sunday driver on a narrow road slows down all traffic behind him. But in the absence of pausing, elongation proceeded much faster — about 70 nucleotides synthesized per second — than has previously been reported.

These two phenomena — pausing and rapid RNA synthesis during elongation — may be crucial for regulating gene expression. “With this sort of mechanism, you could have everything at the ready in case you suddenly needed to rev up transcription,” says Dr. Singer. “Once the ‘paused’ polymerase starts up again, in a very short time you could synthesize a new batch of messenger RNA molecules that might suddenly be needed for making large amounts of a particular protein.”

The other Einstein researchers involved in the study were lead author, Xavier Darzacq (now at Laboratoire de Génétique Moléculaire, Centre National de la Recherche Scientifique, Paris), Yaron Shav-Tal (now at The Mina & Everard Goodman Facility of Life Sciences, Bar-Ilan University, Ramat Gan, Israel), Valeria de Turris and Shailesh M. Shenoy. Other collaborators were Yehuda Brody of Bar-Ilan University and Robert D. Phair of Integrative Bioinformatics, Inc., Los Altos, CA.

Karen Gardner | EurekAlert!
Further information:

Further reports about: Polymerase RNA elongation enzyme transcription

More articles from Life Sciences:

nachricht Here comes the long-sought-after iron-munching microbe
25.10.2016 | Max-Planck-Institut für marine Mikrobiologie

nachricht Novel method to benchmark and improve the performance of protein measumeasurement techniques
25.10.2016 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

First-time reconstruction of infectious bat influenza viruses

25.10.2016 | Life Sciences

Novel method to benchmark and improve the performance of protein measumeasurement techniques

25.10.2016 | Life Sciences

Amazon rain helps make more rain

25.10.2016 | Life Sciences

More VideoLinks >>>