Navigation Links
Divide and define: Clues to understanding how stem cells produce different kinds of cells
Date:5/5/2013

ANN ARBORThe human body contains trillions of cells, all derived from a single cell, or zygote, made by the fusion of an egg and a sperm. That single cell contains all the genetic information needed to develop into a human, and passes identical copies of that information to each new cell as it divides into the many diverse types of cells that make up a complex organism like a human being.

If each cell is genetically identical, however, how does it grow to be a skin, blood, nerve, bone or other type of cell? How do stem cells read the same genetic code but divide into very different types?

Researchers at the University of Michigan have found the first direct evidence that cells can distinguish between seemingly identical copies of chromosomes during stem cell division, pointing to the possibility that distinct information on the chromosome copies might underlie the diversification of cell types.

Scientists in the lab of Life Sciences Institute researcher Yukiko Yamashita explained how stem cells can distinguish between two identical copies of chromosomes and distribute them to the daughter cells in a process called nonrandom chromosome segregation. They also described the genes responsible. Their work is scheduled to be published online May 5 in Nature.

"If we can figure out how and why cells are dividing this way, we might be able to get a glimpse of how we develop into a complete human, starting from a single cell," Yamashita said. "It is very basic science, but understanding fundamental biological processes always has wide-ranging implications that could be exploited in therapeutics and drug discovery."

During the cell division cycle, the mother cell duplicates its chromosomes, generating two identical sets. When the cell divides to become two cells, each cell inherits one set of chromosome copies. In many divisions, the daughter cells are identical to the motherone skin cell becomes two, for instance.

But in a process called asymmetric division, a cell divides into two daughters that are not identicala skin stem cell divides into another skin stem cell and a regular skin cell, for example. In that case, the genetic information within the chromosome copies remains the same, but the type of cell, or "cell fate," is different.

The Yamashita lab used stem cells from the testes of the fruit fly Drosophila to study the process of cell division.

"The Drosophila germ line stem cell can be identified at a single-cell resolution, so they are an ideal model," Yamashita said.

The stem cells cluster and are easy to identify; they divide to produce another germ line stem cell and a differentiating cell called a gonialblast, which goes on to eventually become a sperm cell.

The researchers marked the copies of each chromosome in the Drosophila stem cells as they divided. Using this method, they tracked the tendency of the X and the Y chromosome copies to move to the daughter germ line stem cell or to the gonialblast. They were able to demonstrate that copies of X and Y chromosomes (but not other chromosomes) are distinguished and delivered to the daughter cells with a striking bias.

This is the first direct evidence that cells indeed have an ability to distinguish identical copies of chromosomes and separate them in a regulated manner. This ability has been suspected and hypothesized, but never proven.

"We do not know yet why copies of X and Y chromosomes segregate nonrandomly," Yamashita said. "We think maybe specific epigenetic information is transmitted to the germ line stem cell and to the gonialblast."

The findings suggest that the information on the X and Y chromosomes that makes this division possible is primed during gametogenesisthe process of creating ovum or sperm cellsin the parents.

Many other cells throughout the body are able to divide into two different types, especially during embryonic development. Yamashita's next steps are to explore whether the nonrandom chromosome segregation seen in Drosophila is a widespread phenomenon that is shared by mammals, including humans.

Yamashita is a faculty member of the Life Sciences Institute's Center for Stem Cell Biology, where her laboratory is located and all her research is conducted. She is also an assistant professor in the Department of Cell and Developmental Biology and the Cellular and Molecular Biology Program.

Swathi Yadlapalli of the Life Sciences Institute and U-M Medical School was also an author on the paper.


'/>"/>

Contact: Laura J. Williams
laurajw@umich.edu
734-615-4862
University of Michigan
Source:Eurekalert

Related biology news :

1. Researchers divide enzyme to conquer genetic puzzle
2. Human brain is divided on fear and panic
3. NASDAQ Sets Ex-Dividend Date for Aware, Inc.s Special Cash Dividend of $1.80 Per Share
4. Aware, Inc. Declares Special Cash Dividend of $1.80 Per Share, or Approximately $40 Million in Total
5. Westlake Chemical Increases Quarterly Dividend By Over 150%
6. Divide the Antarctic to protect native species, propose experts
7. Clues to heart disease in unexpected places, Temple researchers discover
8. Scientists decode genome of painted turtle, revealing clues to extraordinary adaptations
9. Researcher offers clues on the origins of life
10. Acoustic monitoring of Atlantic cod reveals clues to spawning behavior
11. Computer simulations yield clues to how cells interact with surroundings
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/1/2016)... , February 1, 2016 ... advancements to drive global touchfree intuitive gesture control market ... --> Rising sales of consumer electronics coupled with ... control market size through 2020 ... electronics coupled with new technological advancements to drive global ...
(Date:2/1/2016)... Fla. , Feb. 1, 2016  Wocket® smart wallet ( www.wocketwallet.com ... and television personality, Joey Fatone . Las Vegas ... greet fans. --> Las Vegas , where ... --> The new video ad was filmed at the Consumer ... appeared at the Wocket booth to meet and greet fans. ...
(Date:1/27/2016)...  Rite Track, Inc. a leading semiconductor equipment and ... Ohio announced today the acquisition of PLUS LLC. ... Austin, Texas , will significantly bolster ... installations and technical support offerings for TEL Track Systems. ... "PLUS has provided world class service including refurbishment, enhancements ...
Breaking Biology News(10 mins):
(Date:2/8/2016)... Conn. , Feb. 8, 2016  NanoViricides, Inc. (NYSE MKT: ... its CEO, Eugene Seymour , MD, MPH, will present information ... at the Waldorf-Astoria Hotel in New York City ... will be in the Windsor Room at 5:30PM EST. Registered attendees ... New York City . --> ...
(Date:2/8/2016)... -- --> --> ... ultra-rapid Point-Of-Care (POC) molecular diagnostics company, today announces that it ... test to be launched on the Company,s io® platform. By ... test is now cleared for sale within the European Union. ... of the io® CT test signals a new era in ...
(Date:2/5/2016)... 2016 ATCC, the premier global biological materials ... medical and life science researchers that are working to ... CDC website . --> ... is a single-stranded RNA virus of the Flaviviridae family, ... and Chikungunya Viruses. Zika virus is transmitted to humans ...
(Date:2/5/2016)... , February 5, 2016 Amarantus ... biotechnology company focused on developing products for Regenerative Medicine, ... Rare Pediatric Disease Designation (RPDD) from the US Food ... with MANF. MANF was previously granted orphan drug designation ... --> Amarantus BioScience Holdings, Inc. (OTCQB: ...
Breaking Biology Technology: