Dynamics of single mRNP nucleocytoplasmic transport and export through the nuclear pore in living ce

Abstract

Real-time visualization of single mRNA-protein complexes reveals messenger ribonucleotide protein transport dynamics in the nucleoplasm and determines the translocation time through the pore to be 500 ms. The presence of introns does not affect movement through the nucleoplasm but increases export efficiency. The flow of genetic information in eukaryotic cells occurs through the nucleocytoplasmic translocation of mRNAs. Knowledge of in vivo messenger RNA export kinetics remains poor in comparison with that of protein transport. We have established a mammalian system that allowed the real-time visualization and quantification of large single mRNA–protein complexes (mRNPs) during export. The in vivo dynamics of bulk mRNP transport and export, from transcription to the nuclear pore complex (NPC), occurred within a 5–40 minute time frame, with no NPC pile-up. mRNP export was rapid (about 0.5 s) and kinetically faster than nucleoplasmic diffusion. Export inhibition demonstrated that mRNA–NPC interactions were independent of ongoing export. Nucleoplasmic transport dynamics of intron-containing and intronless mRNAs were similar, yet an intron did increase export efficiency. Here we provide visualization and analysis at the single mRNP level of the various steps in nuclear gene expression and the inter-chromatin tracks through which mRNPs diffuse, and demonstrate the kinetics of mRNP–NPC interactions and translocation.

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Mor, A., Suliman, S., Ben-Yishay, R. et al. Dynamics of single mRNP nucleocytoplasmic transport and export through the nuclear pore in living cells. Nat Cell Biol 12, 543–552 (2010). https://doi.org/10.1038/ncb2056

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