Featured Research

from universities, journals, and other organizations

Putting The Squeeze On Sperm DNA: Streamlined Sperm Offer New Way To Read Histone Code

Date:
October 1, 2009
Source:
European Molecular Biology Laboratory
Summary:
In the quest for speed, olympic swimmers shave themselves or squeeze into high-tech super-suits. In the body, sperm are the only cells that swim and, as speed is crucial to fertility, have developed their own ways to become exceptionally streamlined. Scientists in Europe have been studying the secrets of speedy sperm. Their work shows how a protein only found in developing sperm cells, Brdt, directs tight re-packaging of sperm DNA.

In the center, a structural model determined by X-ray crystallography shows how the two tags (attached to a short section of the histone protein -- all in cyan) fit neatly into the Brdt pocket (purple). In the background image, hypercompaction by Brdt causes relatively diffuse chromatin (stained blue inside the nuclei of two cells on the top left) to compact and clump together (two on the bottom right).
Credit: EMBL/IBS

In the quest for speed, olympic swimmers shave themselves or squeeze into high-tech super-suits. In the body, sperm are the only cells that swim and, as speed is crucial to fertility, have developed their own ways to become exceptionally streamlined. Scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg and Grenoble, the Institut de Biologie Structurale (IBS) and the Institut Albert Bonniot, both also in Grenoble, have been studying the secrets of speedy sperm. Their work, published in Nature, shows how a protein only found in developing sperm cells, Brdt, directs tight re-packaging of sperm DNA.

Related Articles


Because it is such a long and unwieldy molecule, our DNA is packaged for convenience into a complex structure called chromatin: long DNA strands are wound around proteins called histones. In sperm, however, this package has become even more compact, reducing the size of the sperm head and making it more hydrodynamic.

The nature of chromatin – how open or compact it is – is intricately regulated. Histones are marked with different chemical tags, often several per histone, that act as a code to direct changes in chromatin structure. Different proteins bind to the tags, the combination of which deciphers the code.

Until now, scientists thought that these proteins bind using one or more modular 'domains', with each domain docking to just one tag. However, this new study reports the discovery of an extra level of sophistication. The researchers studied histone binding of a protein called Brdt, finding that it binds most strongly to a histone with two of a particular tag (in this case, acetyl groups) – and, contrary to expectations, uses just one protein domain to do so. "We were very surprised," explains Christoph Mόller of EMBL. "We looked at the structure and saw that the domain forms a pocket, binding both tags at once."

"In sperm, just before the DNA starts to hypercompact, these tags are added throughout the chromatin in a huge wave," explains Saadi Khochbin of the Institut Albert Bonniot. "If Brdt is absent, the extra compaction doesn't take place, and the sperm head would be less streamlined. Male mice lacking Brdt are infertile."

So is the special way that Brdt binds to histone tags important for its unique compacting ability? "We're not sure, but we can speculate," says Christoph Mόller. "One idea is that histones acquire tags sequentially, and only compact when fully tagged. Brdt binds to the last two tags in this sequence, making Brdt-binding the very last step in the process – the final signal for hypercompaction to begin."

"We re-examined the structures of other chromatin-associate proteins and saw that this tag-binding mechanism is likely to be used by them, too, furthering our understanding of how the histone code is read," adds Carlo Petosa of the IBS.

The researchers believe their work will shed light on potential problems in sperm development and are now looking at the role this protein plays in human male infertility.


Story Source:

The above story is based on materials provided by European Molecular Biology Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

European Molecular Biology Laboratory. "Putting The Squeeze On Sperm DNA: Streamlined Sperm Offer New Way To Read Histone Code." ScienceDaily. ScienceDaily, 1 October 2009. <www.sciencedaily.com/releases/2009/09/090930132652.htm>.
European Molecular Biology Laboratory. (2009, October 1). Putting The Squeeze On Sperm DNA: Streamlined Sperm Offer New Way To Read Histone Code. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2009/09/090930132652.htm
European Molecular Biology Laboratory. "Putting The Squeeze On Sperm DNA: Streamlined Sperm Offer New Way To Read Histone Code." ScienceDaily. www.sciencedaily.com/releases/2009/09/090930132652.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) — The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) — Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com
Madagascar Working to Contain Plague Outbreak

Madagascar Working to Contain Plague Outbreak

AFP (Nov. 24, 2014) — Madagascar said Monday it is trying to contain an outbreak of plague -- similar to the Black Death that swept Medieval Europe -- that has killed 40 people and is spreading to the capital Antananarivo. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. 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:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

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