(Press-News.org) If a strand of your DNA was stretched out completely, it would be more than six feet long. It's hard to imagine that it can fit inside the nucleus of one of your cells, but that's exactly how it works.
For much of the last century, scientists have been busy figuring out how DNA is packaged in cells, and have found strong indications that the packaging is integral to how DNA works. The packaging – comprised mostly of an amino acid molecule called a histone – influences the on and off switches of different genes that regulate cellular function and play a role in human diseases ranging from cancer to genetic disorders. Scientists study histones by using antibodies to specific "flavors" of histones that are only very slightly different from one another. The antibodies help to pinpoint what DNA is being packaged by a certain kind of "flavor" of histone, and how that affects gene regulation. Different flavors affect genes differently.
"And this is where it gets complicated," says Jason Lieb, PhD, who led the project. "Many companies make these antibodies that we scientists use in our labs – but there are so many different kinds of histones and types of tests we do that it's just not feasible for the companies to anticipate every single way that a given antibody can be used."
This is a problem, explains Lieb, who is a professor of biology at UNC-Chapel Hill and member of UNC Lineberger Comprehensive Cancer Center, since scientists can't be absolutely certain that the antibody is recognizing a specific "flavor" of histone, or one that is very closely related.
"Histones are essentially the key to the DNA library. They tell you which 'shelves' of that library – or areas of the genome – are open or closed to information moving in and out. But since the differences between the different 'flavors' of histones are often extremely small, and it's likely that an antibody may react with more than one histone or in different ways depending on the type of test being used in the lab. It makes scientific precision very difficult," Lieb notes.
In a paper published today in the journal Nature Structural and Molecular Biology, Lieb and his colleagues from across the country describe how they tested more than 200 antibodies against 57 histone modifications (or flavors) in three different organisms, using three different tests commonly used in this kind of genetic analysis. They found that about 25 percent of antibodies currently sold have a problem with specificity – targeting the anticipated histone – in a given test. They believe that this proportion is likely to remain steady over time.
"So we thought, ok, we need to help ourselves as scientists. We set up a web-based searchable database at http://compbio.med.harvard.edu/antibodies. Our results are there and other scientists can also post their results so that we have a self-sustaining, up-to-date source of information that is really important to scientists working to understand a broad range of genetic phenomena," he said.
INFORMATION:
The research was funded by the National Human Genome Research Institute (part of the United States National Institutes of Health) and included researchers from the Universities of California at Santa Cruz, Berkeley, and San Diego, the Lawrence Berkeley National Laboratory, the Ludwig Institute for Cancer Research, Harvard Medical School, the University of Cambridge (UK), Washington University in St. Louis, Ontario Institute for Cancer Research (Canada) and Rutgers University.
END
New research led by economists at the University of Warwick reveals that medieval England was not only far more prosperous than previously believed, it also actually boasted an average income that would be more than double the average per capita income of the world's poorest nations today.
In a paper entitled British Economic Growth 1270-1870 published by the University of Warwick's Centre on Competitive Advantage in the Global Economy (CAGE) the researchers find that living standards in medieval England were far above the "bare bones subsistence" experience ...
ST. PAUL, Minn. – Women with transient restless legs syndrome (RLS) during pregnancy appear to be at a higher risk of developing a chronic form of RLS later in life or have the same symptoms during future pregnancies, according to new research published in the December 7, 2010, print issue of Neurology®, the medical journal of the American Academy of Neurology. RLS is a sleep-related motor disorder that causes an unpleasant feeling in the legs. The condition generally worsens during rest at night and improves with movement. Symptoms tend to progress with age.
"This is ...
Exposure to death and dying does not negatively affect palliative and hospice care professionals and can actually have positive benefits, states an article in CMAJ (Canadian Medical Association Journal) (pre-embargo link only) http://www.cmaj.ca/embargo/cmaj100511.pdf.
A study of palliative and hospice care professionals in five centres across Canada over was conducted to explore how death affects their personal lives and practices. Since these professionals are constantly around death and dying, it was thought that their insight could benefit others. Participants reported ...
Patients who are starting dialysis too early are at an increased risk of death, found an article in CMAJ (Canadian Medical Association Journal) (pre-embargo link only) http://www.cmaj.ca/embargo/cmaj100349.pdf.
Glomerular filtration rate (eGFR) is a test that describes the flow rate of fluid going through the kidneys and is associated with early dialysis initiation. Current guidelines in the United States place more emphasis on eGFR dialysis timing. Analysis of dialysis registries in the United States and Europe indicates that patients are starting dialysis earlier.
This ...
DALLAS, Dec. 6, 2010 — High blood pressure may help to explain why deaths from heart disease and stroke vary according to geography, race and sex, researchers reported in Hypertension: Journal of the American Heart Association.
"Where you live, your race, and your gender strongly influence your risk of developing high blood pressure as you move from young adulthood into middle age — and hypertension is a major risk factor for heart disease and stroke," said Deborah A. Levine, M.D., M.P.H., lead study author and assistant professor of internal medicine in the Departments ...
Mary Zutter and colleagues, at Vanderbilt University Medical Center, Nashville, have generated data that lead them to suggest that decreased expression of the protein alpha-2 integrin is predictive of tumor dissemination to distant sites and decreased survival in individuals with either breast or prostate cancer.
The researchers first studied the role of the protein alpha-2-beta-1 integrin (which is composed of the alpha-2 integrin protein and the beta-1 integrin protein) in cancer initiation and progression using a clinically relevant, spontaneous mouse model of breast ...
The mammalian embryo relies on physical connections to its mother to survive. After implantation into the wall of the uterus and before the placenta is established, a structure known as the decidua forms and is key to supporting embryonic development. Defective formation of an effective decidua is thought to be a cause of female infertility. A team of researchers, led by Toru Miyazaki, at the University of Tokyo, Japan, has now determined that the protein DEDD is required for the formation of a functional decidua in mice. The authors therefore suggest that it would be interesting ...
Patients in hospitals and healthcare facilities can develop infections as a result of contamination of indwelling medical devices such as catheters with bacteria that are normal inhabitants of the skin of the patient or health care personnel. The bacterium Staphylococcus epidermidis is a major cause of such infections. This is in part because of its ability to form biofilms — surface-attached agglomerations of microorganisms that are extremely difficult to eradicate — on indwelling devices. Michael Otto and colleagues, at the National Institutes of Health, Bethesda, have ...
EDITOR'S PICK: Alpha-2 integrin: a protein predictor of tumor spread?
Mary Zutter and colleagues, at Vanderbilt University Medical Center, Nashville, have generated data that lead them to suggest that decreased expression of the protein alpha-2 integrin is predictive of tumor dissemination to distant sites and decreased survival in individuals with either breast or prostate cancer.
The researchers first studied the role of the protein alpha-2-beta-1 integrin (which is composed of the alpha-2 integrin protein and the beta-1 integrin protein) in cancer initiation and ...
An expert panel sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, has issued comprehensive U.S. guidelines to assist health care professionals in diagnosing food allergy and managing the care of people with the disease.
The Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-sponsored Expert Panel, developed over two years, are intended for use by both family practice physicians and medical specialists. Published online by the Journal of Allergy ...
