Robert Singer and colleagues at the Albert Einstein College of Medicine in New York recently visualized individual Dictyostelium discoideum cells transcribing dscA, a gene that increases in expression during development. Using an in vivo system that tags nacent mRNA, they showed dscA is transcribed in pulses.
"People carry around a picture about these things. Most people would expect that once a gene is on, it?s on. And if it?s off, it?s off. It wouldn?t be flipping between the two all the time. But that?s what they found. They speculate that the reason ...