February 10, 2006

NEUROBIOLOGY: New Signal Found in System Controlling Circadian Activity
Caged rodents living in total darkness will remain relatively inactive for a period of 12 to 14 hours a day, at the end of which they will suddenly jump on their running wheels and start furiously exercising. Sebastian Kraves (right) and Charles Weitz have identified a protein that plays a critical role in regulating these animals’ uncanny circadian behavior. The protein, reported in the February Nature Neuroscience, affords a much fuller view of the complex system underlying this and possibly other circadian behaviors.

NEUROLOGY: MicroRNAs Have Hand in Shaping Synapse
In a study in the Jan. 19 Nature, a team led by Michael Greenberg (right) and Gerhard Schratt offers evidence that a certain microRNA helps control the size of dendritic spines, the small peninsulas at the cell surface where synapses form. MicroRNA, by binding to and blocking the translation of messenger RNA, may help control synaptic development and plasticity by silencing messages until they are needed. The study adds to research showing how these small, noncoding bits of RNA function as important managers in the cell.

ONCOLOGY: Library of 1,000-plus Expressible Breast Cancer Proteins Made Public
In a project called Breast Cancer 1000, researchers in the labs of Joan Brugge and Joshua LaBaer have developed a complementary DNA library for 1,300 breast cancer–related genes, including those known to cause breast cancer and others associated with its progression. The scientists have also demonstrated the utility of this public collection of cDNAs by producing a model system of cells that mimic the human breast. Their study, in the Journal of Proteome Research,confirmed known roles for some proteins in the disease, suggested some novel disease proteins, and indicated new functions for other proteins with known disease roles.

INTEGRITY: Faking Science
In the last 10 years, Photoshop and other imaging software has made it easy and tempting to alter scientific images for innocent or fraudulent purposes. The issue recently became headline news due to scandals involving fabricated data—including manipulated images—in high-profile biomedical research papers. The incidents have provoked discussions about acceptable standards for altering image data and debate about the responsibilities of researchers, journals, and scientific institutions for making, sharing, and enforcing these rules.

CELL BIOLOGY: Skin Grown from Human Embryonic Stem Cells
In an important step toward the therapeutic use of embryonic stem cells, HMS researchers have found a way to improve the production of skin cells from a human embryonic stem (ES) cell line. In the study, Howard Green and colleagues identified some unexpected barriers to the growth and purification of skin cells derived from ES cells. While a human ES cell line readily differentiated into keratinocyte-like cells, the poor growth of the cells made them impossible to expand or purify. Introducing growth-promoting viral genes into the skin cells solved these problems and allowed the production of skinlike sheets from single cells. The findings, which were published in the online edition of Proceedings of the National Academy of Sciences during the week of Jan. 30, show that despite the excitement over the medical uses of ES cells, much work remains to turn the cells into actual therapies.