What was considered an experimental longshot--looking for a molecular motor inside the nucleus of cells--has paid off for Primal de Lanerolle and his colleagues at the University of Illinois at Chicago. In today's issue of Science, they report on finding myosin-1, a chemical cousin of the molecule behind all muscle contraction, within the nucleus. And they further describe how myosin-1 fits into part of the nucleus' machinery for transcribing DNA and appears to power this process. "It was an uphill battle to convince our colleagues," de Lanerolle admits.

Indeed, many scientists believed that myosin--a protein known since the 1920s and found in the cytoplasm of nearly every type of cell--would not exist in the nucleus. But just what drove transcription had remained a mystery all the same. Something had to be responsible for dragging long strands of DNA through the enzymes that transcribe it into messenger RNA, which is equipped to leave the nucleus and help guide protein synthesis at the ribosomes. And for de Lanerolle, myosin didn't seem like such a wild bet. "When your heart beats, when you take a breath, when you digest food or have a baby--anytime cells move or divide," he says, "myosin is involved."

He hopes that applying what science knows about myosin's role in muscle contraction may help them further understand how myosin-1 acts in this "key first step in gene expression." And others hope that the finding will help muscle some more support for doing what is deemed risky science. "What started out as a project to substantiate a highly controversial observation--mysoin in the nucleus--has turned out to be an important key for understanding just how cells perform the rather formidable task of transcribing complex genetic information via DNA," says Eve Barak, acting deputy director of the National Science Foundation's Division of Molecular and Cellular Biosciences. "This is a very significant development."