Another Genetic Link to Obesity?

Scientists have isolated a molecular link between feeling hungry and fidgety behavior. The transcription factor known known as Bsx, which has been isolated in mice, may provide a future target for combating obesity, according to Dr. Mathias Treirer of the European Molecular Biology Laboratory in Heidelberg, Germany (Cell Metab. 2007; 6:450). According to Dr. Treier and colleagues, Bsx gene disruption rescues the obese phenotype of leptin-deficient ob/ob mice by reducing their hyperphagia without increasing their locomotor activity. Thus, Bsx represents an essential factor for orexigen-sensitive NPY/AgRP pacemaker neurons (located in the hypothalamic arcuate nucleus) in neuronal function and locomotor behavior in the control of energy balance. The Bsx gene is conserved across species, so it may also be involved in energy balance in humans. The scientists speculate that mutations in Bsx may explain why some people who habitually overeat become obese while others do not. People with normal copies of the gene may simply be better at matching their activity levels to their food intake.