Gas for all seasons

Researchers have long puzzled over how nitric oxide (NO) plays a vital role in a range of biologoical processes, from dilation of blood vessels to immune defence, learning, memory and even maintaining erections. Now Jonathan Stamler and his colleagues at Duke University in Durham, North Carolina, US, have discovered one important reason why NO molecule is such a jack-of-all-trades. They report that the gas can bind to proteins called transcription factors, which turn genes on and off. This signalling mechanism influenced by NO explains many of NO's biological effects. However, the mechanisms explaining these influences need further research, feel scientists.