PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Protein changes are discovered that control whether a gene functions

2013-08-07
(Press-News.org) A Penn State-led research team has found that changes to proteins called histones, which are associated with DNA, can control whether or not a gene is allowed to function. The changes may be important in maintaining the genes' "expression potential" so that future cells behave as their parent cells did. The discovery, which may have implications for the study of diseases such as cancer, will be published in a print edition of the journal Proceedings of the National Academy of Sciences. The research was led by Lu Bai, an assistant professor of biochemistry, molecular biology, and physics at Penn State University, in collaboration with David Stillman at the University of Utah.

Bai explained that gene expression -- the process by which certain genes are regulated or turned "on" or "off" -- is one of the most fundamental processes in the life of any biological cell. Different programs of gene expression -- even when cells have the same DNA -- can lead to different cellular behavior and function. For example, even though a human muscle cell and a human nerve cell have identical DNA, they behave and function very differently. "Gene expression tends to vary from cell to cell," Bai said. "Misregulation may happen in a small fraction of cells, and these cells may cause disease later on. Therefore it is important to study gene regulation at the single-cell level."

Using a fluorescent video of cell division, Bai and her team were able to observe how a gene called HO was expressed in single yeast cells over multiple cell divisions. Normally, the expression of HO allows budding yeast to change sex -- from "male" to "female" and vice versa. "Interestingly, HO expression -- and thus sex change -- is supposed to occur only in 'mother' cells but not the newly budded 'daughter' cells," Bai explained. After observing the video, team members found that HO was expressed in 98 percent of the mother cells but also in 3 percent of the daughter cells. "The vast majority of both the mother cells and the daughter cells responded as they were supposed to," Bai said. "But, in a small percentage of the cells, the gene regulation went wrong."

The pressing question for Bai's team then was, why did the HO gene regulation fail in a small population of cells -- in 2 percent of the mother cells and 3 percent of the daughter cells? She discovered that the answer seems to lie in histones, a major protein complex associated with DNA. "We found that changes in histone configurations affect the fraction of cells in which the HO expression was misregulated. In addition, we found that, in some conditions, the HO expression can 'remember' itself: If HO is turned on in one cell, it is more likely to be turned on in its progeny cells. We showed that this short-term memory of the HO expression seems to be inherited through histone modifications," Bai said. She added that further study of gene expression, specifically at the level of individual cells, can have important implications for disease research.



INFORMATION:

In addition to Bai and Stillman, other researchers who contributed to this study include Qian Zhang, Youngdae Yoona, Juan Antonio Raygoza Garay, and Michael M. Mwangi from Penn State; Yaxin Yu and Emily J. Parnell from the University of Utah; and Frederick R. Cross from the Rockefeller University.

The research was funded by the National Institutes of Health.

CONTACTS
Lu Bai: lub15@psu.edu, 814-863-4824
Barbara Kennedy (PIO): science@psu.edu, 814-863-4682

IMAGE
A high-resolution image associated with this research is online at http://science.psu.edu/news-and-events/2013-news/Bai8-2013.

CAPTION
This series of three fluorescent images shows yeast cells as they grow from two single cells (left) to a small cell cluster (right). The green color represents the expression of the HO gene. The red color at the bud neck is a marker for cell cycle.

CREDIT
Bai lab, Penn State University

GRANT NUMBERS
National Institutes of Health (GM039067)



ELSE PRESS RELEASES FROM THIS DATE:

Women in urban areas show high rates of postpartum depression, study finds

2013-08-07
Women living in large urban areas are at a significantly higher risk of postpartum depression after five to 14 months of giving birth compared to those living in rural areas, according to a new Canadian study led by Women's College Hospital's Dr. Simone Vigod. The study, published today in the Canadian Medical Association Journal, strongly links geographic location and postpartum depression. The researchers suggest differences in risk factors, including place of birth, social support and history of depression, in combination with geography, may contribute to postpartum ...

Study questions nature's ability to 'self-correct' climate change

2013-08-07
Forests have a limited capacity to soak up atmospheric carbon dioxide, according to a new study from Northern Arizona University. The study, available online in the journal New Phytologist, aimed to explore how rising atmospheric carbon dioxide could alter the carbon and nitrogen content of ecosystems. By performing tests on subtropical woodland plots over an 11-year period, the researchers found that ecosystem carbon uptake was not significantly increased by the high CO2 treatment—in contrast to expectations. While plants did contain more carbon when CO2 levels were ...

New role for Tamoxifen in saving high-risk breast cancer patients

2013-08-07
The global study was led by University of Melbourne and the Peter MacCallum Cancer Centre and published in the Journal of Clinical Oncology today. The study involved about 2,500 women from Europe, North America and Australia who have inherited mutations in BRCA1 or BRCA2, the breast cancer susceptibility genes, and who had been diagnosed with breast cancer. About one-third of these women were placed on tamoxifen. Tamoxifen has been used for decades to treat breast cancer and has recently been shown to prevent breast cancers in many women. Until now, there has been ...

Diets of pregnant women contain harmful, hidden toxins

2013-08-07
RIVERSIDE, Calif. — Pregnant women regularly consume food and beverages containing toxins believed to pose potential risks to developing fetuses, according to researchers at the University of California in Riverside and San Diego, suggesting that health care providers must do more to counsel their patients about the dangers of hidden toxins in the food supply. In a peer-reviewed study published in the July issue of Nutrition Journal — "Consumption habits of pregnant women and implications for developmental biology: a survey of predominantly Hispanic women in California" ...

Sericin can alleviate diabetic hippocampal injury

2013-08-07
Preliminary studies by Dr. Zhihong Chen and colleagues from Chengde Medical College have shown that sericin might improve aberrant Akt signaling, decrease heme oxygenase-1 expression in the hippocampus and cerebral cortex, and reduce the apoptosis of hippocampal neurons in diabetic rats, thus protecting the nervous system. Recently, it is reported that the growth hormone/insulin-like growth factor 1 axis undergoes abnormal changes in diabetes mellitus, which aggravate the disease progression and trigger complications. To improve diabetes mellitus and its chronic complications, ...

Breast cancer surgery linked to swollen arm syndrome

2013-08-07
Breast cancer survivors who have extensive surgery are four times more likely to develop the debilitating disorder arm lymphoedema, a QUT study has found. The findings in a new paper Incidence of unilateral arm lymphoedema after breast cancer: a systematic review and meta-analysis published in the prestigious journal The Lancet Oncology, reveal the invasiveness of surgery to treat breast cancer increases the risk of developing arm lymphoedema. Lead author of the study Tracey DiSipio, from QUT's Institute of Health and Biomedical Innovation, said women who had undergone ...

Insect 'soup' serving up rapid biodiversity monitoring

2013-08-07
Griffith University researchers have taken part in an international study which has discovered a fast but accurate means of identifying changes to the biodiversity of a region. And the secret lies in crushed up insect "soup". Traditionally, many thousands of hours have been spent by researchers gathering, classifying and recording insects and animals in order to understand the natural ecology of a region. Any changes to the biodiversity of that area could then be determined only by more labour-intensive collecting and recording. Research published today in the journal ...

UCSB study reveals that overthinking can be detrimental to human performance

2013-08-07
(Santa Barbara, Calif.) –– Trying to explain riding a bike is difficult because it is an implicit memory. The body knows what to do, but thinking about the process can often interfere. So why is it that under certain circumstances paying full attention and trying hard can actually impede performance? A new UC Santa Barbara study, published today in the Journal of Neuroscience, reveals part of the answer. There are two kinds of memory: implicit, a form of long-term memory not requiring conscious thought and expressed by means other than words; and explicit, another kind ...

Why don't we all get Alzheimer's disease?

2013-08-07
Though one might think the brains of people who develop Alzheimer's disease (AD) possess building blocks of the disease absent in healthy brains, for most sufferers, this is not true. Every human brain contains the ingredients necessary to spark AD, but while an estimated 5 million Americans have AD – a number projected to triple by 2050 – the vast majority of people do not and will not develop the devastating neurological condition. For researchers like Subhojit Roy, MD, PhD, associate professor in the Departments of Pathology and Neurosciences at the University of ...

The odd couple

2013-08-07
This image was taken by the Very Large Telescope (VLT) at ESO's Paranal Observatory in Chile — the best place in the southern hemisphere for astronomical observing. But even without the help of telescopes like the VLT, a glance towards the southern constellation of Dorado (The Swordfish or Dolphinfish [1]) on a clear, dark night reveals a blurry patch which, at first sight, appears to be just like a cloud in the Earth's atmosphere. At least, this may have been explorer Ferdinand Magellan's first impression during his famous voyage to the southern hemisphere in 1519. Although ...

LAST 30 PRESS RELEASES:

High-quality nanodiamonds for bioimaging and quantum sensing applications

New clinical practice guideline on the process for diagnosing Alzheimer’s disease or a related form of cognitive impairment or dementia

Evolution of fast-growing fish-eating herring in the Baltic Sea

Cryptographic protocol enables secure data sharing in the floating wind energy sector

Can drinking coffee or tea help prevent head and neck cancer?

Development of a global innovative drug in eye drop form for treating dry age-related macular degeneration

Scientists unlock secrets behind flowering of the king of fruits

Texas A&M researchers illuminate the mysteries of icy ocean worlds

Prosthetic material could help reduce infections from intravenous catheters

Can the heart heal itself? New study says it can

Microscopic discovery in cancer cells could have a big impact

Rice researchers take ‘significant leap forward’ with quantum simulation of molecular electron transfer

Breakthrough new material brings affordable, sustainable future within grasp

How everyday activities inside your home can generate energy

Inequality weakens local governance and public satisfaction, study finds

Uncovering key molecular factors behind malaria’s deadliest strain

UC Davis researchers help decode the cause of aggressive breast cancer in women of color

Researchers discovered replication hubs for human norovirus

SNU researchers develop the world’s most sensitive flexible strain sensor

Tiny, wireless antennas use light to monitor cellular communication

Neutrality has played a pivotal, but under-examined, role in international relations, new research shows

Study reveals right whales live 130 years — or more

Researchers reveal how human eyelashes promote water drainage

Pollinators most vulnerable to rising global temperatures are flies, study shows

DFG to fund eight new research units

Modern AI systems have achieved Turing's vision, but not exactly how he hoped

Quantum walk computing unlocks new potential in quantum science and technology

Construction materials and household items are a part of a long-term carbon sink called the “technosphere”

First demonstration of quantum teleportation over busy Internet cables

Disparities and gaps in breast cancer screening for women ages 40 to 49

[Press-News.org] Protein changes are discovered that control whether a gene functions