Biomedical Beat - A monthly digest of research news from NIGMS

June 20, 2007

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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. To read additional news items, visit NIGMS News. To check out free NIGMS publications, go to the order form.

Cool Movie: Fly Cells Live


If a picture is worth a thousand words, what's a movie worth? For researchers studying cell migration, a new "documentary" of fruit fly cells (bright green) traversing an egg chamber could answer longstanding questions about cell movement. Historically, researchers have been unable to watch this cell migration unfold in living ovarian tissue in real time. But by developing a culture medium that allows fly eggs to survive outside their ovarian homes, scientists can now observe the nuances of cell migration as it happens. Such details may shed light on how immune cells move to a wound and why cancer cells spread to other sites. Courtesy of cell biologist Denise Montell of Johns Hopkins University School of Medicine.

Full story
Montell lab home page (no longer available)
Article abstract (from the June 2007 issue of Developmental Cell)

Viral DNA Helps Cold Sores Recur

A cold sore might go away, but the virus that caused it won’t. That’s because the herpes simplex virus 1 (HSV-1) hides out in nerve cells, silencing all but one viral gene. This stealthy maneuver stems from a DNA segment called an “insulator,” according to new work by geneticist Jumin Zhou of the Wistar Institute. Insulators can prevent other DNA elements from activating genes. The finding marks the first time an insulator, found in a range of organisms, has been identified in a virus. By keeping just a fragment of the viral genome active, the HSV-1 insulator allows infected cells to survive and the virus to re-emerge. It also presents a potential drug target for clearing up cold sores once and for all.

Full story
Zhou home page
Article abstract (from the May 2007 issue of the Journal of Virology)

Natural Rhythms Linked to Body Weight

Biological clocks set the sleep-wake cycle in humans and most creatures, and new research suggests they also help control body weight. Knowing that the gene nocturnin plays a role in biological clock activity, neuroscientist Carla Green of the University of Virginia bred lab mice without the gene. When she fed these mice a high-fat diet, the rodents stayed thin. Mice with the nocturnin gene eating the same unhealthy diet, however, gained considerable weight and had fatty livers. The research suggests a new link between biological clocks and body weight.

This work was also supported by NIH's National Eye Institute and National Institute of Diabetes and Digestive and Kidney Diseases.

Full story
Green home page
Article abstract (from the June 5, 2007, issue of PNAS)

Scientists Steer Bacteria Toward Chemical Targets

Bacteria (green) programmed to move toward the chemical theophylline migrate along an S-shaped theophylline path. Control bacteria (red) stay put.
High res. image
(260 KB JPEG)

If scientists could steer bacteria to specific targets, the microbes could deliver drugs to tumor cells, remove pollutants from the soil, or perform other useful tasks. In a step in this direction, Justin Gallivan, a chemist at Emory University, has successfully programmed E. coli to detect and follow specific chemical signals. To do this, Gallivan’s team equipped the bacteria with a riboswitch, a piece of RNA that turns genes on or off when bound to certain molecules. The researchers believe that riboswitches can help guide other types of bacteria toward medically or environmentally significant targets.

Full story (no longer available)
Gallivan home page (no longer available)
Article abstract (from the May 30, 2007, issue of the Journal of the American Chemical Society)

Promise of New, Improved Gleevec®

Gleevec® is a drug used to treat rare forms of leukemia and gastrointestinal cancer. But the cancers can develop resistance to it. By adding just four atoms at a key point in the drug, a research team led by bioengineer Ariel Fernandez of Rice University has synthesized a version of the molecule that appears to be effective against the drug-resistant cancers. If the molecule works in humans, it could provide new treatment options for those whose cancer no longer responds to Gleevec®.

Full story
Fernandez lab home page (link is no longer available)
Article abstract (from the May 1, 2007, online edition of Cancer Research)