Featured Research

from universities, journals, and other organizations

Copy of the genetic makeup travels in a protein suitcase

Date:
May 25, 2012
Source:
Universität Bonn
Summary:
Researchers have caught on film, in real time, the process of messenger RNA leaving the cell nucleus.

Oral gland nuclei. The nucleus is the inner oval area in each of the different frames. The messenger RNA in the nuclei were labeled with glowing fluorescent dyes and laser radiation.
Credit: Copyright Jan Peter Siebrasse / University of Bonn

Scientists from the Institute for Physical and Theoretical Chemistry at the University of Bonn have succeeded for the first time in the real time filming of the transport of an important information carrier in biological cells that is practically unmodified. The study shows how so-called messenger RNA leaves the cell's nuclear membrane and from the cell nucleus enters the cytoplasm.

This paper has now been published in the Proceedings of the National Academy of Sciences (PNAS).

The blueprint of all living beings is stored in their genetic material. In higher organisms this is stored in the well-protected cell nucleus. "Here a kind of copier works around the clock to make copies of the information needed at the time," says first author Jan Peter Siebrasse from the Institute for Physical and Theoretical Chemistry at the University of Bonn. The copies contain the information which the cells need to produce vital enzymes or other cell building materials. These copies consist of messenger RNA which travels on random paths to the membrane of the cell nucleus and from there through the nuclear pores into the cytoplasm which fills out the cells like jello.

Stringent quality control at the pore

The working group has found out that the messenger RNA lingers briefly at the pores in the membrane of the nucleus before it is finally transported out -- presumably for a final "quality control" or simply because it has to adjust in order to leave via the pore exit. The export process lasts in total only a few hundredths of a second to several seconds. "In all likelihood, the process needs much longer for larger, voluminous messenger RNA molecules than for smaller ones," adds Prof. Ulrich Kubitscheck, head of the working group Biophysical Chemistry and senior author of the publication.

Interestingly enough, only about every fourth collision between arriving messenger RNA and the cell nucleus leads to a successful export. Here, two kinds of processes can be distinguished: On the one hand, brief collisions with the nuclear membrane where presumably no pore is hit, and, on the other hand, those transports that are slowly aborted perhaps on account of a deficient quality control.

RNA is packed in a suitcase made of "protein"

The RNA is packed in a type of "suitcase" made of proteins for transporting. "And it is quite a chunk," grins Prof. Kubitscheck. This is why some of his colleagues presume there are helpers on the outside of the cell's nucleus which pull the "suitcase" through the pores, a theory which the professional physicist together with the molecular biologist Jan Peter Siebrasse are currently investigating

Just what exactly happens en route from the copier to the pores has been clarified in recent years among others by Prof. Kubitscheck's working group at the University of Bonn. "Key experiments on this were undertaken by the biologist Dr. Roman Veith, whose doctorate thesis was awarded this year's Dr. Edmund ter Meer Ph.D. thesis prize from the university society," reports Prof. Kubitscheck. For these experiments the messenger RNA was altered so that it glowed when illuminated with a laser beam. This enabled the researchers to trace the path of individual molecules containing copies of the genetic material in living buccal gland cells of a mosquito type with up to 500 pictures per second. A light microscope with a high speed camera made the observation possible.

Researchers constructed special light microscope

Once the transport processes between the "copier" and the cell nuclear membrane were understood, Prof. Kubitscheck and his colleagues turned their attention in recent years to the direct transport process through the nuclear pores. In order to observe this process, they took a number of years to construct a highly sensitive light microscope which works on the basis of target illumination. It creates delicate pictures of living samples and, in the process of taking pictures with high frequency, creates an unusually strong contrast.

Process is of fundamental biological interest

The question of how the messenger RNA enters the cell from the cell nucleus is of fundamental interest in biology, a fact Prof. Thoru Pederson (University of Massachusetts Medical School) underscores in his comment which accompanies the article paper presented by the Bonn-based scientists. In recent years, there have been two publications on this performed by working groups in the USA and Israel. In these studies, however, the messenger RNA has been altered with additives making the molecules at least double their volume. By contrast, the Bonn-based working group modified the messenger RNA in a negligible way, as Prof. Pederson determined.


Story Source:

The above story is based on materials provided by Universität Bonn. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. P. Siebrasse, T. Kaminski, U. Kubitscheck. Nuclear export of single native mRNA molecules observed by light sheet fluorescence microscopy. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1201781109

Cite This Page:

Universität Bonn. "Copy of the genetic makeup travels in a protein suitcase." ScienceDaily. ScienceDaily, 25 May 2012. <www.sciencedaily.com/releases/2012/05/120525103753.htm>.
Universität Bonn. (2012, May 25). Copy of the genetic makeup travels in a protein suitcase. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2012/05/120525103753.htm
Universität Bonn. "Copy of the genetic makeup travels in a protein suitcase." ScienceDaily. www.sciencedaily.com/releases/2012/05/120525103753.htm (accessed September 21, 2014).

Share This



More Plants & Animals News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) — The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) — Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) — The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) — A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins