Featured Research

from universities, journals, and other organizations

Young sperm, poised for greatness, but are they under-achievers?

Date:
May 19, 2014
Source:
University of Utah
Summary:
It was long assumed that the joining of egg and sperm launched a dramatic change in how and which genes were expressed. Instead, new research shows that totipotency is a step-wise process, manifesting as early as in precursors to sperm, called adult germline stem cells (AGSCs), which reside in the testes.

Sperm illustration (stock image). Typically, sperm precursors live a mundane life. They divide, making more cells like themselves, until they receive the signal instructing them to mature into sperm. There is evidence, however, that these cells have the potential to do more.
Credit: © Luk Cox / Fotolia

In the body, a skin cell will always be skin, and a heart cell will always be heart. But in the first hours of life, cells in the nascent embryo become totipotent: they have the incredible flexibility to mature into skin, heart, gut, or any type of cell.

It was long assumed that the joining of egg and sperm launched a dramatic change in how and which genes were expressed. Instead, new research shows that totipotency is a step-wise process, manifesting as early as in precursors to sperm, called adult germline stem cells (AGSCs), which reside in the testes.

The study was co-led by Bradley Cairns, Ph.D., University of Utah professor of oncological sciences, and Huntsman Cancer Institute investigator, and Ernesto Guccione, Ph.D., of the Agency for Science Technology and Research in Singapore. They worked closely with first author and Huntsman Cancer Institute postdoctoral fellow, Saher Sue Hammond, Ph.D. The research was published online in the journal Cell Stem Cell.

Typically, sperm precursors live a mundane life. They divide, making more cells like themselves, until they receive the signal instructing them to mature into sperm.

There is evidence, however, that these cells have the potential to do more. Under the unusual conditions that promote the cells to form dense cancerous masses called testicular teratomas, the young sperm transform into precursors of skin, muscle, and gut.

This realization prompted the investigators to examine the gene program within sperm precursors. They wondered, would it be like that of a cell that is destined to become a single cell type, or like that of a cell with the potential to become anything?

The answer, they found, is that the sperm precursors are somewhere in between. The most telling evidence is the status of a quartet of genes: Lefty, Sox2, Nanog, and Prdm14. When activated, the genes can trigger a cascade of events that give cells stem cell properties. In cells limited to becoming one cell type, the genes are silent.

Yet in sperm precursors, the genes bear a code of chemical tags, called methylation groups, indicating that the four genes are silenced, but poised to become active. In other words, embedded within these cells, is the potential to become totipotent.

Cairns compares the tags on the poised genes to bookmarks. "Sperm cells and their precursors put 'bookmarks' at all the important genes they need to access quickly." Once fertilization occurs, he explains, cells have to become fully totipotent in a short amount of time. "Then, when the sperm and egg come together, all you have to do is complete the job that you had already started."

The engineering principal, as he calls it, ensures the transition occurs rapidly and accurately.

The result is just one of many that together comprise a detailed playbook documenting genetic and epigenetic changes that take place along the journey to becoming totipotent. The rich resource will guide future studies toward a deeper understanding of totipotency, cancer, and fertilization.


Story Source:

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


Journal Reference:

  1. Saher Sue Hammoud, Diana H.P. Low, Chongil Yi, Douglas T. Carrell, Ernesto Guccione, Bradley R. Cairns. Chromatin and Transcription Transitions of Mammalian Adult Germline Stem Cells and Spermatogenesis. Cell Stem Cell, 2014; DOI: 10.1016/j.stem.2014.04.006

Cite This Page:

University of Utah. "Young sperm, poised for greatness, but are they under-achievers?." ScienceDaily. ScienceDaily, 19 May 2014. <www.sciencedaily.com/releases/2014/05/140519104743.htm>.
University of Utah. (2014, May 19). Young sperm, poised for greatness, but are they under-achievers?. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2014/05/140519104743.htm
University of Utah. "Young sperm, poised for greatness, but are they under-achievers?." ScienceDaily. www.sciencedaily.com/releases/2014/05/140519104743.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) — West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) — A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) — Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) — Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) 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