Dynamics and transport of nuclear RNA

The messenger RNA (mRNA) molecule passes the genetic information from the genome to the protein synthesis machinery. Decades of study of the spatial characteristics of mRNA distribution in fixed cells and tissues particularly by electron microscopy and in situ hybridization approaches, have revealed the sites of synthesis in relation to the nuclear DNA, and the paths taken en route to the nuclear pore. These studies are now complemented by experiments performed in living cells using fluorescent tags that specifically target mRNA transcripts. The use of high-end microscopy equipment improving the detection of mRNA molecules, together with the advent of new fluorescent tags and original means by which to label the mRNAs, allow us to spy on the mRNA within its natural context of the living cell. High-resolution time-lapse imaging has brought to light the dynamics of single molecules of mRNA during RNA polymerase II transcription, nucleoplasmic transport of mRNA-protein complexes (mRNPs), and the final nuclear event of mRNA export through the nuclear pore complex.