News Briefs; December 2000; Scientific American Magazine; by Diane Martindale; 2 Page(s)
For the first time, scientists have seen what it takes to move the long stretches of DNA through the enzyme factories that translate the genetic code into messagesmade of RNA: a muscle inside the nucleus of the cell. The molecular motor, called myosin I b, is a slightly altered version of the common myosin I protein, previously found only in the cytoplasm, where it helps to traffic organelles and other structures there. Physiologist Primal de Lanerolle of the University of Illinois discovered that myosin I b has a unique sequence that allows the motor to attach to the enzyme factories in the nucleus and to power the DNA strands. The work appears in the October 13 Nature.-D.M.
The toxic fallout of heavy industries is leaving America's backyard and traveling to the most remote and pristine regions in North America. Barry Commoner of Queens College in New York City, in collaboration with the Commission for Environmental Cooperation, an agency created under the North American Free Trade Agreement, modeled the movement of dioxin released from trash-burning incinerators, cement kilns and other industries in Canada, Mexico and the U.S. He found that the cancer-causing dioxin could travel thousands of miles from its source, poisoning the land and eventually entering the food chain, where it accumulates in animal fat. Humans are exposed when they eat contaminated fat.