%0 Journal Article
%T Molecular Beacons: Powerful Tools for Imaging RNA in Living Cells
%A Ricardo Monroy-Contreras
%A Luis Vaca
%J Journal of Nucleic Acids
%D 2011
%I Hindawi Publishing Corporation
%R 10.4061/2011/741723
%X Recent advances in RNA functional studies highlights the pivotal role of these molecules in cell physiology. Diverse methods have been implemented to measure the expression levels of various RNA species, using either purified RNA or fixed cells. Despite the fact that fixed cells offer the possibility to observe the spatial distribution of RNA, assays with capability to real-time monitoring RNA transport into living cells are needed to further understand the role of RNA dynamics in cellular functions. Molecular beacons (MBs) are stem-loop hairpin-structured oligonucleotides equipped with a fluorescence quencher at one end and a fluorescent dye (also called reporter or fluorophore) at the opposite end. This structure permits that MB in the absence of their target complementary sequence do not fluoresce. Upon binding to targets, MBs emit fluorescence, due to the spatial separation of the quencher and the reporter. Molecular beacons are promising probes for the development of RNA imaging techniques; nevertheless much work remains to be done in order to obtain a robust technology for imaging various RNA molecules together in real time and in living cells. The present work concentrates on the different requirements needed to use successfully MB for cellular studies, summarizing recent advances in this area. 1. Introduction A wealth of experimental evidence accumulated to this date illustrates the wide range of cellular functions conducted by ribonucleic acids (RNAs). In many occasions these functions involve RNA transport from one cellular compartment to another or into the same compartment to specialized regions. In order to accomplish this, RNA molecules are under a specific and selective control via expression levels and/or stability in a spatial-temporal manner. Different methods developed to purify RNA [1¨C3] from cell populations or tissues have provided relevant information about the relative concentration of RNA in cells, or cellular compartments, yet these methods provide limited information about the spatial-temporal distribution of RNAs and their dynamic transport. The integral understanding of cellular process in which RNA is involved, requires a method that reveals RNA localization in real time in a subcellular context in living cells. The information obtained from this type of assays promise to impulse the advancement in molecular biology, medical research, and diagnostics. Many methods have been developed to measure RNA expression levels between different cell populations, such as the polymerase chain reaction (PCR) [4], northern blot [5],
%U http://www.hindawi.com/journals/jna/2011/741723/