Ancient Throwback: New Technology


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Unknown Object
biosensor reveals riboswitch activity
Today the management “posts” in the cell are occupied by proteins; but eons ago, when single-celled organisms were beginning to make their mark on Earth and life was simple, the living world might have been an “RNA world.” Recent findings suggest that RNA molecules, single strands of nucleic acids that are far less sophisticated than proteins, are capable of performing many of the cell’s main regulatory functions.
Riboswitches, discovered several years ago in bacteria, are segments of RNA that can bind to certain substances, thereby regulating the levels of these substances in the cell. Only one riboswitch has so far been found in higher organisms: The thiamin (vitamin B1) riboswitch regulates thiamin biosynthesis in numerous organisms that produce this vitamin – from the most ancient bacteria to highly developed plants. Dr. Asaph Aharoni and Samuel Bocobza of the Plant Sciences Department investigated this lone plant riboswitch. The scientists revealed the mechanism by which the riboswitch senses the presence of thiamin in the cell nucleus and makes sure the levels of this essential vitamin are neither too high nor too low by turning its production on or off as needed.
They may be ancient mechanisms, but riboswitches could be the basis of sophisticated future biotechnologies. Aharoni and Bocobza engineered reporter genes – genes that glow in fluorescent colors under the microscope when activated – that responded to thiamin levels as the riboswitches did. When inserted into plants, these reporters lit up whenever thiamin levels fell. This sort of reporter gene-riboswitch combination could pave the way to the design of live biosensors for all sorts of applications.  
Dr. Asaph Aharoni’s research is supported by the Sir Charles Clore Research Prize; the William Z. and Eda Bess Novick New Scientists Fund; the Henry S. and Anne Reich Family Foundation; Sir Harry Djanogly, CBE; Mrs. Louise Gartner, Dallas, TX; Mr. and Mrs. Mordechai Segal, Israel; and the estate of Fannie Sherr, New York, NY. Dr. Aharoni is the incumbent of the Adolpho and Evelyn Blum Career Development Chair of Cancer Research.