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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... November 17, 2011

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Worm sperm

Cool Image: Moving Questions

Tom Roberts • Florida State University

Two worm sperm shimmy across a microscope slide. Unlike most cells that rely on motor proteins to propel themselves forward, worm sperm use tiny fibers at their front ends. Putting the fibers together and taking them apart sets the cells in motion. In a new advance, researchers disassembled the worm sperm cell and rebuilt the parts used for motion so that they worked just as they do in a live cell. This approach may serve as a model for studying how other cells, including cancerous ones, get around.
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The fruit fly midgut, showing intestinal (blue and red) and stem (green) cells. Credit: Lucy O'Brien and David Bilder.

Stem Cells Enable Adaptive Resizing of Fly Intestine

David Bilder • University of California, Berkeley

Many tissues and organs, such as muscles or the liver, grow or shrink with usage. Even the intestine can be affected, shrinking to a third of its normal size in hibernating animals. Scientists have uncovered a mechanism by which this type of "organ adaptation" occurs. Working in fruit flies, they found that food intake causes the intestine to produce insulin, stimulating the division of intestinal stem cells and the expansion of the gut. The findings may suggest new approaches for treating obesity and diabetes in humans.
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Caption: The fruit fly midgut, showing intestinal (blue and red) and stem (green) cells. Credit: Lucy O'Brien and David Bilder. High res. image (JPG, 59KB)
Zelda protein. Credit: PLoS Genetics.

Protein Zelda Flips Mother's Genes Off, Zygote's Genes On

Christine Rushlow • New York University

For a short time, a fertilized egg (zygote) relies on maternal molecules before its own genetic processes kick in. Researchers have now identified a protein, called Zelda, that appears to coordinate this transition. Zelda turns off maternal genes and activates zygotic genes that form body parts, grow nerve cells and control other processes in the developing embryo. Although the research was done in fruit flies, the scientists suspect that molecules like Zelda also regulate the maternal to zygotic transition in humans. If so, studies of the protein could shed light on the molecular causes of certain birth defects. Read more... Link to external Website

Caption: Zelda protein (tagged green) plays a major role in the early development of the fruit fly embryo. Credit: PLoS Genetics. High res. image (JPG, 35KB)

Gut Bacteria May Play a Part in Cholesterol Drug's Effectiveness

Rima Kaddurah-Daouk • Duke University

Cholesterol-lowering drugs can be effective for some people, yet ineffective for others. A team of researchers recently discovered that the type of bacteria that reside in our gut may partly explain the variable response. The scientists found that three bile acids produced by certain bacteria in the gut appear to play a role in a person's response to simvastatin, a common cholesterol-lowering medicine. These findings suggest that understanding the impact of the microbes that inhabit us on the medicines we take will be essential for personalizing medical therapies. Read more... Link to external Website

Caption: Researchers identified three bile acids in people who had a positive response to simvastatin.
Neuromuscular junction of a fruit fly larva. Credit: Thomas Jongens.

Impaired RNA Editing Linked to Fragile X Syndrome

Thomas Jongens • University of Pennsylvania School of Medicine

Disrupting the FMR1 gene causes Fragile X syndrome, the most common form of inherited intellectual disability and the most common genetic cause of autism. Now, new research in fruit flies shows that FMRP, the protein encoded by FMR1, is involved in RNA editing, a process that tweaks a gene's sequence much like a newspaper editor might modify a reporter's first draft. Fruit fly larvae lacking FMRP demonstrated impaired editing of certain RNAs and structural defects in the neuromuscular junction, an important communication channel between nerves and muscles. FMRP's newly discovered role in RNA editing provides insight into the molecular basis of Fragile X syndrome and offers new strategies for treating the condition. Read more... Link to external Website

NIH's National Institute of Mental Health also supported this work.

Caption: Mistakes in RNA editing cause structural defects in the neuromuscular junction of a fruit fly larva. Credit: Thomas Jongens. High res. image (JPG, 45KB)

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This page last reviewed on November 17, 2011