Featured Research

from universities, journals, and other organizations

Cell nuclei harbor factories that transcribe genes

Date:
September 27, 2013
Source:
Université de Genève
Summary:
Copies of the DNA exit the nucleus to be read and translated into proteins in the cell cytoplasm. The transit between the nucleus and the cytoplasm takes place through the nuclear pores, genuine "customs agents" that monitor the import-export between these two compartments. Researchers have just discovered how nuclear pores also regulate the production speed of these DNA copies.

Our genetic heritage is contained -- and protected -- in the nucleus of the cells that compose us. Copies of the DNA exit the nucleus to be read and translated into proteins in the cell cytoplasm. The transit between the nucleus and the cytoplasm takes place through the nuclear pores, genuine "customs agents" that monitor the import-export between these two compartments. Françoise Stutz, professor in the Faculty of Science at the University of Geneva (UNIGE), Switzerland, and her team have just discovered how nuclear pores also regulate the production speed of these DNA copies. This work, published in the journal Molecular Cell, reveals a new role for each nucleus' several hundred pores, which constitute as many microscopic factories of gene transcription.

Gene activity is not only determined by the sequence of the DNA, but also by the dynamic three-dimensional structure of the genome. The spatial distribution of genes inside the cell nucleus and their movement towards specific compartments influence their expression as well as chromosome stability and repair. One of these compartments is none other than the nuclear pore, present in the hundreds or thousands, depending on the type of nucleus.

If the gene does not go to the pore…

Pores, composed of many different proteins, the nucleoporins, cross the nuclear envelope and monitor the heavy traffic of the molecules, which takes place between the nucleus and the cytoplasm of the cell. "Moreover, we know that, once activated, many genes attach to the pores to be transcribed there," notes Françoise Stutz, professor in the department of Cell Biology at UNIGE, Switzerland. To try to understand why, the researcher carried out experiments with baker's yeast. This unicellular fungus is often used as a model organism, because it works as a mammalian cell, though it is easier to handle.

When yeast ingests galactose, it will transform this sugar into energy thanks to an enzyme called GAL1. However, the gene encoding this enzyme is normally repressed by various proteins that mask its activation domain. "The whole complex is maintained in this state, blocked by the attachment of a tiny protein called SUMO," explains Lorane Texari, team member and first author of the article.

… the pore comes to it

After the yeast absorbs the sugar, the GAL1 gene is relocated to the nuclear pore. "We have discovered that the gene anchors itself with the help of an enzyme called Ulp1, which will remove the mini-protein SUMO. This will enable an array of factors to position themselves on the activated gene and to initiate its transcription," says the PhD student. The many copies thereby produced will then be exported directly into the cytoplasm. Once they are decoded, the instructions that they contain will enable the production of the enzyme GAL1, so that the yeast can use the galactose as fuel.

The nuclear pores thus create an environment conducive to the efficient production of gene copies. "For that matter, these microscopic transcription factories seem to have their equivalent in mammalian cells. We also find various enzymes anchored to the nucleoporins, including the enzyme responsible for removing the SUMO protein. However, given the size of their nucleus, much larger than yeast's, it is the nucleoporins that move towards the activated genes and not vice versa," explains Françoise Stutz. These mobile nucleoporins result, once again, from the infinite ingenuity demonstrated by the cells for adapting to new conditions of life.


Story Source:

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


Journal Reference:

  1. Lorane Texari, Guennaëlle Dieppois, Patrizia Vinciguerra, Mariana Pardo Contreras, Anna Groner, Audrey Letourneau, Françoise Stutz. The Nuclear Pore Regulates GAL1 Gene Transcription by Controlling the Localization of the SUMO Protease Ulp1. Molecular Cell, 2013; 51 (6): 807 DOI: 10.1016/j.molcel.2013.08.047

Cite This Page:

Université de Genève. "Cell nuclei harbor factories that transcribe genes." ScienceDaily. ScienceDaily, 27 September 2013. <www.sciencedaily.com/releases/2013/09/130927123414.htm>.
Université de Genève. (2013, September 27). Cell nuclei harbor factories that transcribe genes. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2013/09/130927123414.htm
Université de Genève. "Cell nuclei harbor factories that transcribe genes." ScienceDaily. www.sciencedaily.com/releases/2013/09/130927123414.htm (accessed April 24, 2014).

Share This



More Plants & Animals News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) — A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) — Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
Raw: Kangaroo Rescued from Swimming Pool

Raw: Kangaroo Rescued from Swimming Pool

AP (Apr. 24, 2014) — A kangaroo was saved from drowning in a backyard suburban swimming pool in Australia's Victoria state on Thursday. Australian broadcaster Channel 7 showed footage of the kangaroo struggling to get out of the pool. (April 24) Video provided by AP
Powered by NewsLook.com
Monkeys Are Better At Math Than We Thought, Study Shows

Monkeys Are Better At Math Than We Thought, Study Shows

Newsy (Apr. 23, 2014) — A Harvard University study suggests monkeys can use symbols to perform basic math calculations. Video provided by Newsy
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