To visualize the synthesis of biomolecules in living organisms, artificial small molecules can be added to and incorporated by the cell's own biosynthetic machinery. Subsequently, the modified biomolecules containing the artificial units can be selectively labelled with fluorescent substances. Until now, this approach had one major limitation: the substances used for labelling were toxic and caused cell death.
Anne Neef, a PhD student from the Institute of Organic Chemistry at the University of Zurich, has developed a new substance that can replace the natural nucleoside thymidine in DNA biosynthesis. This fluorinated nucleoside called "F-ara-Edu" labels DNA with little or no impact on genome function in living cells and even whole animals. "F-ara-Edu" is less toxic than previously reported compounds used for DNA labelling and it can be detected with greater sensitivity.