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The National Institute of General Medical Sciences (NIGMS), one of the National Institutes of Health, supports all research featured in this digest. Although only the lead scientists are named, coworkers and other collaborators also contributed to the findings.

In This Issue... July 18, 2013

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Atom-by-atom structure of a bacterium ribosome. Credit: Arto Pulk, University of California, Berkeley.

Cool Image: Making the Ribosome Move

Jamie Cate and John Tainer • Lawrence Berkeley National Laboratory

This is the first atomic-resolution image of the protein-building ribosome bound to the protein that controls its motion, EF-G (center of the picture). Using high-energy protein crystallography, researchers obtained the pair's structure and used it to learn that EF-G moves the ribosome by reshaping itself after interacting with an energy-carrying molecule. EF-G 's reconfiguration allows the ribosome to manipulate mRNA and tRNA, two molecules needed for protein building in the cell. The finding could lead to better antibiotics that interfere with the ribosome's movement in bacteria and kills them. Read more. Link to external Website

Photo of candies.

A New Tool to Check Sugar Consumption

Diane O'Brien and Bert Boyer • University of Alaska Fairbanks

Scientists have found a biomarker that can be used to measure a person's sugar consumption. Corn and sugarcane, which are among the most prominent sources of sugars, have unique ratios of two forms of carbon, carbon-12 and carbon-13, that persist in people after they consume sugars made from the plants. Scientists can estimate the amount of sugar intake by looking for those unique ratios in a small hair or blood sample. The new method can be used to calibrate and increase the accuracy of other measurements of sugar consumption as well as aid other diet-related research.
Read more... Link to external Website

Caption: A new method measures sugar consumption from a hair or blood sample.
Sperm cell. Credit: Judith Stoffer

How a Genetic Disease Makes Itself More Likely to Pass from Father to Child

Norman Arnheim • University of Southern California

About 1 in 2,000 children are born with Noonan syndrome, a genetic disease associated with short stature, congenital heart defects and a unique craniofacial structure. Scientists have found why the disorder is more common than expected in children of older dads. Changes in one of the genes for Noonan syndrome give affected stem cells in the fathers' testes an advantage over other stem cells. As a result, the stem cells and sperm carrying these mutations are found in higher numbers than usual in the testes of older men, increasing the likelihood that they will produce children with Noonan syndrome. This finding may lead to a better understanding of this disorder and others that occur more often in the children of older fathers. Read more... Link to external Website

This work also was supported by NIH's National Heart, Lung, and Blood Institute.

Caption: Stem cells in the testes of older men are more likely to carry a mutation for Noonan syndrome.
Photo of a mammogram x-ray film.

Who Benefits from Breast Cancer Prevention Drugs? These Genes Might Tell

James Ingle • Mayo Clinic

Researchers matched two gene variations previously unconnected to breast cancer with a positive response to long-term cancer prevention treatment using tamoxifen or raloxifene. Both medications are sometimes given to women who are at high risk of breast cancer, but the drugs can have side effects, including blood clots and increased risk of endometrial cancers. The variants are present in or nearby to genes that affect expression of the gene BRCA1, which is strongly associated with the development of breast cancer. Women with the beneficial version of the two variants were more than 5 times less likely than other high-risk individuals to get cancer while taking tamoxifen or raloxifene. The results could enable doctors to better predict who will benefit from treatment to prevent breast cancer. Read more...

This work also was supported by NIH's National Cancer Institute.

Caption: Two gene variants previously unrelated to breast cancer can help predict the effectiveness of two drugs used to prevent the disease in high-risk individuals.
DNA structure.

Switching Off Muscular Dystrophy

Matthew Disney • The Scripps Research Institute, Florida Campus

A group of compounds can switch off the genes responsible for adult-onset muscular dystrophy. This is one of the first times scientists have been able to turn off a genetic, hereditary disease. Chemists screened more than 300,000 small molecules from a previous NIH-funded study and isolated compounds that bind to and inhibit an RNA complex critical to the disease's progression. When other scientists on the team introduced the compounds into in vitro muscle tissue affected by the disease, the RNA complex did not form, allowing the damage to the muscle cells to be reversed. The small molecules will serve as a tool for studies on muscular dystrophy and investigations into their use as potential disease treatments. Read more... Link to external Website

This work also was supported by NIH's National Cancer Institute, National Institute of Arthritis and Musculoskeletal and Skin Diseases and National Institute of Neurological Disorders and Stroke.

Caption: A group of compounds can switch off the gene for an adult-onset form of muscular dystrophy.

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For more information about Biomedical Beat, please contact the editor, Emily Carlson, in the NIGMS Office of Communications and Public Liaison at 301-496-7301. The text in this newsletter is not copyrighted, and we encourage its use or reprinting.

This page last reviewed on July 18, 2013