Navigation Links
Male infertility: It's all about the package
Date:5/13/2014

Cold Spring Harbor, NY Infertility is generally thought of as a woman's problem. In fact, more than 3 million men across America also experience it. Today, researchers from Cold Spring Harbor Laboratory (CSHL) describe a key event during sperm development that is essential for male fertility. A team led by CSHL Professor Alea Mills explains how a protein controls DNA packaging to protect a man's genetic information.

The sperm is a simple delivery vehicle for a man's genetic information. The highly specialized cell is little more than a DNA bundle powered by molecular motors. As such, it is necessarily tiny: from head to tail a sperm cell is only about 50 micrometers long (1/500th of an inch), invisible to the naked eye. An egg is 30 times larger. The sperm's small size has its benefits less bulk to carry while searching for an egg but it also presents significant challenges. A man's genetic material must be very tightly packaged to fit within a minuscule space.

This organizational problem is not unique to sperm. Every cell in our body contains a full human genome, which spans nearly two meters (6 feet) if unfurled. To contain this massive length of DNA, cells tightly compress our genetic information. In every cell nucleus, DNA is wrapped like thread around protein spools, called histones. The thread can be easily unwound at any time to allow access to the genetic information. In sperm, the packaging problem is much more acute, as its DNA is even more condensed. The spool-like histones are replaced with tiny proteins called protamines. This repackaging process, called chromatin remodeling, is absolutely essential for male fertility.

In work published today in Nature Communications, Mills and her team identify a protein, called Chd5, as a key regulator of chromatin remodeling during sperm development. Mills and Wangzhi Li, PhD, lead author on the study, removed both copies of the Chd5 gene from male mice. They discovered that these males had severe fertility defects, ranging from low sperm counts to decreased sperm motility. The defective sperm failed to fertilize eggs when in vitro fertilization (IVF) was performed.

Mills has been interested in Chd5 since the time that her team first discovered it in 2007 as a potent tumor suppressor, one that can stop cells from becoming cancerous. "We know this ability has something to do with chromatin remodeling -- that when defective, causes normal cells to transform into tumors," says Mills. "But the most dramatic chromatin reorganization occurs when specialized cells carrying our genetic blueprint develop into sperm cells. It makes sense that Chd5 would be functioning there, too."

This, indeed, is what Mills and her team found. When Chd5 is missing, chromatin remodeling is disrupted. Histones are not efficiently replaced with protamines to repackage DNA, resulting in a more uneven, less condensed genome.

This change in DNA packaging has dramatic effects on the DNA itself. In the absence of Chd5, the double helix becomes damaged, breaking at multiple points throughout the genome. "So in addition to infertility, loss of Chd5 may put future generations the rare embryos that do get fertilized with defective sperm at risk for disease," says Mills. "Chd5 may protect a person from medical conditions related to DNA damage and spontaneous mutations, like cancer and autism."

The team is actively studying the role of Chd5 in human fertility. They analyzed Chd5 levels using data from testes biopsies obtained from men with fertility defects. "We found that men with more severe defects had the lowest levels of Chd5," says Mills. "While it is only a correlation at this point, we are eager to understand fully how Chd5 affects sperm development in humans."


'/>"/>

Contact: Jaclyn Jansen
jjansen@cshl.edu
516-367-8455
Cold Spring Harbor Laboratory
Source:Eurekalert  

Related biology news :

1. Leading cfaed scientists organize international workshop about DNA-based microchips
2. Reconstructed ancient ocean reveals secrets about the origin of life
3. The human food connection: A new study reveals more about our relationship to food
4. What songbirds tell us about how we learn
5. Elevating geosciences in the southeastern US: New ideas about old terranes
6. Neck ribs in woolly mammoths provide clues about their decline and eventual extinction
7. What singing fruit flies can tell us about quick decisions
8. The frozen truth about glaciers, climate change and our future
9. New evidence raises questions about the link between fatty acids and heart disease
10. Study provides new information about the sea turtle lost years
11. Graduate student makes major discovery about seal evolution
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Male infertility: It's all about the package
(Date:3/22/2017)...   Neurotechnology , a provider of high-precision ... the release of the SentiVeillance 6.0 ... recognition using up to 10 surveillance, security and ... new version uses deep neural-network-based facial detection and ... a Graphing Processing Unit (GPU) for enhanced speed. ...
(Date:3/20/2017)... PMD Healthcare announces the release of its ... System (WMS), a remote, real-time lung health monitoring and ... is a Medical Device, Digital Health, and Chronic Care ... innovative solutions that empower people to improve their healthcare ... developed the first ever personal spirometer, Spiro PD, which ...
(Date:3/9/2017)... and MOUNTAIN VIEW, Calif. , March ... Made Simple," and 23andMe , the leading personal ... food choices.  Zipongo can now provide customers with personalized ... health goals and biometrics, but also genetic markers impacting ... Zipongo,s personalized food decision support platform uses ...
Breaking Biology News(10 mins):
(Date:3/22/2017)... 22, 2017  UBM and the Massachusetts Medical ... extended partnership and the third annual Massachusetts Medtech Week. ... 21 st Annual MassMEDIC Conference held in ... 3-4, 2017. MassMEDIC will feature ... President and CEO, Scott Whitaker , at ...
(Date:3/22/2017)... MarketNewsUpdates.com News Commentary  ... The traditional ways to ... as of late due to the rise of the opioid ... dramatic impact on patient,s quality of life as Biotech and ... new forms of opioid formulations that prevent abuse. Biotech and ...
(Date:3/22/2017)... , ... March 21, 2017 , ... Okyanos Cell Therapy ... as part of their live events series, “Stem Cell Therapy: The Next Phase in ... under the 2013 Stem Cell Research and Therapy Act, Okyanos maintains a ...
(Date:3/22/2017)... ... March 21, 2017 , ... ... its innovative Quantum peristaltic pump with patented ReNu single-use (SU) cartridge technology. ... standard for high-pressure feed pumps in SU tangential flow filtration (TFF), virus ...
Breaking Biology Technology: