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Archive - Jan 6, 2014

Mystery m6A Modification of mRNA Governs Half-Life of Molecule

Researchers had known for several decades that a certain chemical modification exists on messenger ribonucleic acid (mRNA), which is essential to the flow of genetic information. But only recently did experiments at the University of Chicago show that one major function of this modification governs the longevity and decay of RNA, a process critical to the development of healthy cells. The chemical modification on mRNA in question is called N6-methyladenosine (m6A). A recent study by U. Chicago scientists and collaborators reveals how the m6A modification on mRNA could affect the half-life of mRNA that in turn regulates cellular protein quantities. That discovery could provide fundamental insights into healthy functioning and disorders such as obesity, diabetes, and infertility. The m6A modification "affects a huge number of messenger RNAs in human cells, and yet we did not know its exact function," said Dr. Chuan He, professor in chemistry at U. Chicago and a recently selected investigator of the Howard Hughes Medical Institute. He, Xiao Wang and 11 co-authors from U. Chicago, University of California, San Diego, and Peking University reported their findings on m6A in the January 2, 2014 issue of Nature. RNA in human cells becomes constantly depleted as it produces proteins, an instability that is essential to biology. "Whenever a cells starts to differentiate, transform into a different type of cell, it needs to express a different set of proteins using a different set of messenger RNA," Dr. He said. "It can't be the original set." The disposal of old RNA allows for the addition of new RNA and the production of different proteins. The Nature study documents that this process is regulated by the insertion or removal of a methyl group, a chemical group commonly found in organic compounds.

10-Year Study Shows Keys to Successful Long-Term Weight Loss Maintenance

Researchers from The Miriam Hospital in Providence, Rhode Island, together with collaborators, have published one of the first studies of its kind to follow weight loss maintenance for individuals over a 10-year period. The results show that long-term weight loss maintenance is possible if individuals adhere to key health behaviors. The study is published in the January 2014 issue of the American Journal of Preventive Medicine. J. Graham Thomas, Ph.D., is the lead author on a 10-year observational study of self-reported weight loss and behavior change in nearly 3,000 participants. The participants had lost at least 30 pounds and had kept if off for at least one year when they were enrolled in the National Weight Control Registry (NWCR).vThe participants were then followed for 10 years. Dr. Thomas explains that the goal of the study was to determine how well they kept the weight off and to identify predictors of successful weight loss maintenance. Dr. Thomas says, "On average, participants maintained the majority of their weight loss over this extended follow-up period, and better success was related to continued performance of physical activity, self-weighing, low-fat diets, and avoiding overeating." Other findings from the study show that more than 87 percent of the participants were estimated to be still maintaining at least a 10 percent weight loss at years five and 10. The researchers found that a larger initial weight loss and longer duration of maintenance were associated with better long-term outcomes. Conversely, they found that decreases in physical activity, dietary restraint and self-weighing along with increases in fat intake were associated with greater weight regain. Dr. Thomas concludes, "This is one of the only studies to follow weight loss maintenance over such a long term.