Keeping stem cells from changing fates
2010-09-09
(Press-News.org) Johns Hopkins researchers have determined why certain stem cells are able to stay stem cells.
The report in the June 4 issue of Cell Stem Cell reveals that an enzyme that changes the way DNA is packaged in cells allows specific genes to be turned on and off, thereby preventing a stem cell from becoming another cell type.
Each cell has to fit in 6 feet of highly organized and carefully packaged DNA. Some regions of the DNA are more tightly compacted than others and this structure is dynamic. There are specific enzymes that change how condensed the DNA is to help turn genes on and off. The genes that are turned off generally are found in tightly condensed DNA. To turn genes on, the DNA around those genes is loosened so that activators and other proteins can interact with the DNA.
The Johns Hopkins researchers believed that restructuring the DNA by proteins that make up chromosomes could play a role in deciding if a stem cell was going to change into another cell or stay a stem cell, since change in the DNA packaging would allow for many genes to be turned off and other genes to be turned on.
By genetically engineering flies to lack several proteins involved in packaging DNA, in the stem cells of the testes in fruit flies, the research team found that if the enzyme NURF is removed from testis stem cells, the stem cells disappeared. A constant supply of stem cells in the testes is responsible for making cells that eventually become sperm. More staining of the testes with colored markers showed that these cells hadn't gone away completely, but were becoming another cell type, sperm cells.
"This experiment was really hard to do," says Erika Matunis, Ph.D., professor of cell biology from the Johns Hopkins School of Medicine. "As soon as you remove NURF from these cells, they leave, so you have to take a lot of samples to see how the cells are moving, since we are not looking at living moving cells but rather individual flashes in time."
So how does NURF keep stem cells as stem cells? NURF can both turn on and turn off genes. "We still don't know what is happening in this case with how NURF regulates genes to keep stem cells from changing," says Matunis.
Matunis' group last year discovered proteins that were able to prevent stem cells from becoming other types of cells in the fruit fly testes. Now they showed that these same proteins also work with NURF to keep stem cells from changing. "By any means this isn't the only pathway though, it's just the one we know more about" says Matunis. "It's probably a tangled hair ball of all kinds of signals going on in these cells that prevent these stem cells from differentiating."
NURF keeps stem cells from changing in fruit fly testes, but whether NURF keeps other stem cells from changing still needs to be tested. Matunis believes that proteins similar to NURF will factor into whether a cell decides to change or not in other cell types.
INFORMATION:
Graduate student Christopher Cherry is an author on the paper in addition to Erika Matunis.
Funding for the research was provided by grants from the NIH/NICHD.
On the web:
Matunis website: http://www.hopkinsmedicine.org/cellbio/dept/MatunisProfile.html
Cell Stem Cell: http://www.cell.com/cell-stem-cell/
END
ELSE PRESS RELEASES FROM THIS DATE:
2010-09-09
As children in Western cultures grow, they learn to place numbers on a mental number line, with smaller numbers to the left and spaced further apart than the larger numbers on the right. Then the number line changes to become more linear, with small and large numbers the same distance apart. Children whose number line has made this change are better at remembering numbers, according to a new study published in Psychological Science, a journal of the Association for Psychological Science.
Remembering numbers is an important skill—in life, which is full of social security ...
2010-09-09
New Rochelle, NY, September 9, 2010—A subset of children with asthma suffers from severe, treatment-resistant disease associated with more illness and greater allergic hypersensitivity, according to the results of the National Heart, Blood, and Lung Institute's Severe Asthma Research Program (SARP), presented in a recently published article in Pediatric Allergy, Immunology, and Pulmonology, a peer-reviewed journal published by Mary Ann Liebert, Inc. (www.liebertpub.com). The article is available free online at www.liebertpub.com/pai
Asthma is the most common chronic lung ...
2010-09-09
New Rochelle, NY, September 9, 2010—Patients who choose to spend their last days at home with specialized care and monitoring can safely be given opioids to control pain and other symptoms without reducing survival time, according to a study published in Journal of Palliative Medicine (JPM), a peer-reviewed journal from Mary Ann Liebert, Inc.(www.liebertpub.com). The article is available free online at www.liebertpub.com/jpm
The use of high-dose opioids to relieve symptoms such as pain and shortness of breath in hospital- or hospice-based end-of-life care is proven to ...
2010-09-09
Amsterdam, The Netherlands, September 2010
More than 7,000 psychiatrists, neurologists, psychologists and neuroscience researchers from all over the world met at the 23rd Congress of the European College of Neuropsychopharmacology (ECNP) from 28 August to 1 September 2010 in Amsterdam.
The ECNP Congress is the largest scientific meeting on mental health in Europe, and this year included 46 sessions presented by more than 150 distinguished speakers from 20 countries. In addition, three poster sessions with in total more than 750 poster presentations from scientists ...
2010-09-09
A risk may be posed, for example, by luggage left in a public place which may contain explosives or other dangerous substances. Terror attacks based on this tactic have already claimed many civilian lives. Luggage surveillance is particularly important at airports, railway stations, trade fairs, and public spaces in nationally significant infrastructure.
The aim of the SUBITO project, which is funded by the European Commission, is to improve image analysis technology in existing CCTV systems. With the help of an application developed as part of the project, cameras recognise ...
2010-09-09
Montreal, September 9th, 2010 – An investigation published in The Journal of Sexual Medicine has found that male partners who express greater support, attention and sympathy to women's chronic vulvovaginal pain may trigger more pain, but also increase sexual satisfaction in female partners.
Women who took part in the study, conducted by the University of Montreal and University of Montreal Hospital Research Centre, suffer from a condition called provoked vestibulodynia (PVD). A condition that affects 12 percent of premenopausal women, PVD can impair sexual functioning ...
2010-09-09
Behind every coincidence lies a plan - in the world of classical physics, at least. In principle, every event, including the fall of dice or the outcome of a game of roulette, can be explained in mathematical terms. Researchers at the Max Planck Institute for the Physics of Light in Erlangen have constructed a device that works on the principle of true randomness. With the help of quantum physics, their machine generates random numbers that cannot be predicted in advance. The researchers exploit the fact that measurements based on quantum physics can only produce a special ...
2010-09-09
Fresh insight into how plants slow their growth in cold weather could help scientists develop crops suited to cooler environments.
Researchers have shown for the first time that a gene – known as Spatula – limits the growth of plants in cool temperatures, possibly helping them adjust to cool conditions.
Researchers at the University of Edinburgh, who took part in the study, believe that by manipulating the gene, they could produce the opposite effect – enabling development of crops that grow well in cold climates.
Scientists studied the Spatula gene in a weed known ...
2010-09-09
One third of the world's population is infected with Mycobacterium tuberculosis (MTB), which leads to tuberculosis (TB), a leading cause of death world-wide. A new discovery, led by a team of researchers from Case Western Reserve University School of Medicine, offers hope for new approaches to the prevention and treatment of TB. The team's discovery of a novel mechanism that may contribute to immune recognition of MTB is published in the September issue of Nature Structural and Molecular Biology.
Most individuals with TB recover from the initial infection and become asymptomatic, ...
2010-09-09
Essays
Title: The Prospects for Personalized Medicine
Author: Shara Yurkiewicz
Summary: Ten years after the release of a working draft of the human genome, major changes have made their way into medical practice, the marketplace, research, and policy.
Title: Personalized Medicine's Ragged Edge
Author: Leonard M. Fleck
Summary: The phrase "personalized medicine" has a built-in positive spin. But little attention has been given to some challenging issues of justice it raises. Some people will clearly benefit a lot, some people will clearly not benefit at all, and ...
LAST 30 PRESS RELEASES:
[Press-News.org] Keeping stem cells from changing fates
