MicroRNAs make big splash in apoptosis

undreds of microRNAs are encoded in animal genomes, yet the function of only two were known until recently. That number has now doubled with the identification of two miRNAs, mir14 and bantam , both of which appear to regulate cell death in Drosophila , according to reports from Peizhang Xu, Bruce Hay (California Institute of Technology, Pasadena, CA), and colleagues and from Julius Brennecke, David Hipfner, Alex Stark, Rob Russell, and Stephen Cohen (EMBL, Heidelberg, Germany). Cohen’s group went looking for genes involved in growth control using a P-element–based overexpression screen. They found bantam , an miRNA, that when overexpressed causes a suppression of cell death and an increase in cell proliferation. Using a computer program designed to identify miRNA targets, they found that bantam controls apoptosis by binding to hid mRNA, suppressing its translation and blocking its pro-death activity. They H