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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... June 15, 2011

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Chemical tags on histones help guide early progenitor cells (yellow channel in center of image) toward forming liver cells (blue, semi-circle in lower right quadrant of image).

Cool Image: Predicting Cell Fates

Kenneth Zaret • University of Pennsylvania

In this embryo, chemical tags on histones—the spools around which DNA is wound—help guide early progenitor cells (yellow) toward forming liver cells (blue). Working with mice, researchers found that distinct patterns of chemical tags on the histones marked progenitor cells for the liver versus the pancreas. The markings could be used to predict cell fates, resolving a longstanding question in stem cell biology about what determines a cell's destiny and possibly offering an important advance in regenerative medicine for conditions like liver failure and type 1 diabetes.
Read more... Link to external Website

NIH's National Institute of Diabetes and Digestive and Kidney Diseases and National Institute of Mental Health also supported this work.
C. elegans given harsh touches change direction. Credit: Shawn Xu.

Touching on the Mechanisms of Pain

Shawn Xu • University of Michigan

Most animals can distinguish between harsh and gentle touches, but until now scientists haven't been certain how the mechanism behind this sensation works. New research using the roundworm C. elegans shows that separate sets of neurons detect painful, harsh touches as opposed to gentle, harmless ones. After a harmful touch, the worms often react by changing their direction of movement. Because C. elegans is widely used to study sensation, these findings could help inform how other animals feel and respond to pain.

Caption: C. elegans given harsh touches change direction. Credit: Shawn Xu. Watch Video Link to external Website.
Image of the a primitive model cell dividing. Credit: Christine Keating lab.

Structure from Simple Cells

Christine Keating • Penn State University

When a cell divides into daughter cells, DNA provides important genetic information. A new study suggests that less celebrated parts of the cell—cytoplasm and the membrane, for example—also play a key role in cell division. Scientists built basic, non-living model cells that lacked important machinery like genes and enzymes. Even without these parts, the cells split into daughters, showing that such simple cells can still divide in complex, structured ways. This work could shed light on how similar cells sans DNA gave rise to the origins of life. Read more... Link to external Website

Caption: A primitive model cell divides. Credit: Christine Keating lab.
Notum helps planarians re-grow heads from anterior wounds. Credit: Peter Reddien.

Finding the Gene in Regeneration

Peter Reddien • Whitehead Institute for Biomedical Research

Planarians, freshwater flatworms, have the rare ability to regenerate their entire body from only a tiny slice of tissue. Scientists have found that a gene called notum helps planarians regulate what parts they re-grow after an injury. The gene acts on the worm's head-facing end and works against a pathway that usually blocks the growth of a new head elsewhere on the body. Because notum has ancient evolutionary roots, it could play a role in tissue repair in other species. Read more... Link to external Website

Caption: Notum helps planarians re-grow heads from anterior wounds. Credit: Peter Reddien. High res. image (JPG, 78KB)
Two mice, one white and one black.

More Precise Mouse Models

Gary Churchill • Jackson Laboratory

Mice are used all over the world to study how drugs and diseases work in humans. But according to new findings, lab mice don't represent the diversity of wild mice or humans because they are bred from a very small gene pool. To help overcome this problem, scientists created an online database of genomic data on 162 different strains of lab mice. Now other researchers can use the database to carefully choose experimental mouse DNA, selecting for strains that will generate research findings that can better generalize to humans. Read more... Link to external Website

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

Caption: A new database charts lab mouse diversity. Credit: Bill Branson, NIH.

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This page last reviewed on June 15, 2011