In this week's Science, a multi-institute team of researchers report on the discovery that a specific mutation that causes nerve cell death only functions in the presence of a second mutation, offering insights into how a person's genetic makeup can influence disease development. In mouse experiments, the scientists found that the loss of a specific protein involved in the ribosome recycling led to ribosome stalling and widespread neurodegeneration, but only in one particular genetic background. They ultimately discovered that the ribosome-related mutation was dependent on a transfer RNA gene for the apoptotic phenotype.
And in Science Translational Medicine, Chinese scientists describe how defects in the expression of the PTEN protein contribute to the B-cell hyperactivity that characterizes lupus. Specifically, PTEN, which regulates normal molecular signaling in B cells, was expressed at lower levels than usual in B cells taken from untreated lupus patients. These decreased levels were associated with higher levels of lupus activity and severity. The team also shows how PTEN is controlled by a number of microRNAs, and that defects in one in particular — microRNA-7 — may be behind the aberrant PTEN behavior that contributes to lupus.