The findings, to be published in the May 1 issue of Development (available online on April 18th) are key for understanding human development. According to Dr. Levin, this work shows a unified model for understanding embryonic development, and is therefore likely to provide important insight into human development. "Biased left-right asymmetry is both a fascinating and medically important phenomenon," said Levin. "Problems with left/right asymmetry are responsible for a wide-range of birth defects in humans including conditions that affect the heart, the digestive system, the lungs and the brain. Building on our earlier research, we are gaining a significant understanding of asymmetry and getting closer to understanding its impact on humans. This fascinating ion pump has additional roles during development that are a goldmine of novel cellular control mechanisms."
Dr. Levin's team looked at molecular genetic and physiological characterization of a novel, early, biophysical event that is crucial for correct asymmetry: the flow of hydrogen ion or H+ flux. A pharmacological screen implicated the H+-pump H+-V-ATPase in Xenopus (frog) embryo asymmetry, where it directs left- and right-sided gene expression. The cell cytoskeleton is responsible for the LR-asymmetric localization of this pump during the first few cell cleavages in frog embryos. H+-flux across plasma membranes is thus asymmetric at the four- and eight-cell stages, and this asymmetry requires H+-V-ATPase activity. Artificially equalizing the asymmetry in H+