(1) Single Molecule Imaging of Biological Functions

Makio TOKUNAGA

　In the post-genome era, novel methods are needed to elucidate functions of molecules found in genome. Recently, single molecule techniques have been developed out of in vitro researches of motor proteins. We are trying to spread out this new technique from in vitro to in vivo and from motor proteins to other biological molecules. Imaging of single fluorescent molecules has been achieved in a relatively simple manner using objective-type total internal reflection fluorescence microscopy (TIRFM). It is found that single molecule imaging in vivo is realized using the objective-type TIRFM. Furthermore, I'm developping new microscopy to achieve followings: 1) Quantitative imaging of molecular numbers or concentrations in vivo. It is essential to minimize the background light. 2) Imaging in vivo of interacting molecules and activated molecules.