Neurons Use Viruses to Share Information and Learn

When genes are activated, the instructions encoded within their DNA are first transcribed into a related molecule called RNA. Shepherd’s colleague Elissa Pastuzyn showed that the Arc shells can enclose RNA and move it from one neuron to another. And that’s basically what retroviruses do—they use protein shells to protect their own RNA as it moves between cells in a host. So our neurons use a repurposed viral gene to transmit genetic information between each other in an oddly virus-like...

 Vitamins Come from Living Things

Every vitamin is made by living cells — either our own, or in other species. Vitamin D is produced in our skin, for example, when sunlight strikes a precursor of cholesterol. A lemon tree makes vitamin C out of glucose. Making a vitamin is often an enormously baroque process. In some species, it takes 22 different proteins to craft a vitamin B12 molecule. While a protein may be made up of thousands of atoms, a vitamin may be made up of just a few dozen. And yet, despite their small size, v...