Featured Research

from universities, journals, and other organizations

New mechanism discovered in meiosis: How modification of an enzyme governs critical processes in sexual reproduction

Date:
May 3, 2013
Source:
Max-Planck-Gesellschaft
Summary:
Scientists have made an important discovery in meiosis research. They have identified a new mechanism that plays an important role in meiosis.

A protein structure (synaptonemal complex) forms between the homologous chromosomes in the presence of the step-2 enzyme modified with SUMO. If the step-2 enzyme cannot be modified with SUMO, the complex is completely absent.
Credit: © Martin Xaver, modified by Andrea Pichler

The Research Group headed by molecular biologist Andrea Pichler from the Max Planck Institute of Immunobiology and Epigenetics in Freiburg has made an important discovery in meiosis research. Pichler and her group have identified a new mechanism that plays an important role in meiosis.

Starting point of the research

Meiosis, also called reductional division, is a key process in sexual reproduction. It shuffles parental genetic material and thus guarantees genetic variety.

In order to control various biological processes, cells are able to selectively alter properties of their proteins, such as their lifespan, activity level, binding partners, or localization of the proteins. This is accomplished, for example, by attaching one or more Small Ubiquitin-like Modifier (SUMO) proteins. This takes place in three sequential enzyme-dependent steps. Scientists have assumed that the enzyme for step 2 was solely an intermediate.

The breakthrough

As the scientists in Freiburg have now discovered, the step-2 enzyme is itself modified by the SUMO protein and thereby alters how it functions. The surprising effect: the conventional activity of the enzyme is switched off by this change and instead, a new function gained. It works together with the activated, unaltered enzyme in the formation of SUMO chains. If this effect is blocked, there are serious consequences: the protein structure (synaptonemal complex) that forms between the homologous chromosomes can no longer be established.

The researchers' new insights

A tiny amount -- less than one percent -- of the SUMO-modified step-2 enzyme is sufficient to form a normal protein structure (left image). Researcher Helene Klug from Pichler's team: "The smallest amount of the altered enzyme together with the unmodified enzyme is sufficient to form an activated complex, which then carries out the meiosis specific SUMO modifications."

"In the beginning, the results of the biological and biochemical experiments were completely contradictory, although the data were absolutely sound. We were therefore convinced that both sets of observations were correct. Explaining this contradiction led us then to the new mechanism," according to Pichler, who heads the study. In extensive and complicated biochemical experiments, the researchers were additionally able to reveal, for the first time, how this enzyme complex carries out the formation of SUMO chains.

After fifty years of research on the synaptonemal complex, these new insights are setting a new course: "This is the first time we can study the loss of the synaptonemal complex with practically no secondary effects and we hope to unveil its secret. That allows us to investigate the consequences for meiosis and thus for development of the gametes," say Franz Klein and Martin Xaver, collaborators and meiosis researchers at the Max F. Perutz Laboratories in Vienna.

Pichler and her team were already able to demonstrate in 2008 that self-tagging by the step-2 enzyme in mammalian cells has an influence on precisely which proteins are tagged with SUMO. In order to uncover the biological function for this form of regulation, the research team switched to baker's yeast (Saccharomyces cerevisiae), a simpler organism. "Now that we know where we need to search, we also want to switch back again to the mammalian system and investigate the role of this enzyme regulation more closely there," says Pichler. "In addition, we want to better understand the function of the discovered baker's yeast enzyme complex in the meiotic chromosomal structure."


Story Source:

The above story is based on materials provided by Max-Planck-Gesellschaft. Note: Materials may be edited for content and length.


Journal Reference:

  1. Helene Klug, Martin Xaver, Viduth K. Chaugule, Stefanie Koidl, Gerhard Mittler, Franz Klein, Andrea Pichler. Ubc9 Sumoylation Controls SUMO Chain Formation and Meiotic Synapsis in Saccharomyces cerevisiae. Molecular Cell, 2013; DOI: 10.1016/j.molcel.2013.03.027

Cite This Page:

Max-Planck-Gesellschaft. "New mechanism discovered in meiosis: How modification of an enzyme governs critical processes in sexual reproduction." ScienceDaily. ScienceDaily, 3 May 2013. <www.sciencedaily.com/releases/2013/05/130503094133.htm>.
Max-Planck-Gesellschaft. (2013, May 3). New mechanism discovered in meiosis: How modification of an enzyme governs critical processes in sexual reproduction. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2013/05/130503094133.htm
Max-Planck-Gesellschaft. "New mechanism discovered in meiosis: How modification of an enzyme governs critical processes in sexual reproduction." ScienceDaily. www.sciencedaily.com/releases/2013/05/130503094133.htm (accessed September 18, 2014).

Share This



More Plants & Animals News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chimp Violence Study Renews Debate On Why They Kill

Chimp Violence Study Renews Debate On Why They Kill

Newsy (Sep. 17, 2014) — The study weighs in on a debate over whether chimps are naturally violent or become that way due to human interference in the environment. Video provided by Newsy
Powered by NewsLook.com
Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) — The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) — Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) — Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) 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