Access to and from the nucleus is of vital importance to cellular life, as information, material and information need to be exchanged between nucleus and cytoplasm of the cell. High resolution imaging in space and time has opened a window into the dynamics of the cellular life of bio-molecules. These new, light based, techniques do offer sufficient sensitivity and spatial resolution, below the diffraction limit, to observe individual molecular movement in the living cell, but hold the promise to add a wealth of dynamic information, previously inaccessible.

Nucleocytoplasmic transport has been one model system for single molecule tracking in cells, resulting in a limited set of data on import processes to the nucleus adding to our understanding of this crucial process. However, the dynamics of nuclear pore mediate export are still completely unknown. We have recently been able to sheet first insights into this process by tracking ?-actin messenger RNA (mRNA) crossing nuclear pores in real time in living cells. Here we present ongoing work on mRNA export, both in yeast and mammalian cells using super-registration microscopy and technology developments towards fast 3D imaging to reveal the routes taken by RNA to reach the nuclear periphery.