Average translocation velocity of mRNP (mRNA-protein complex) through NPC (Nuclear Pore Complex)

Value 0.65 µm/sec Range: ±0.37 µm/sec
Organism Human Homo sapiens
Reference Mor A, Suliman S, Ben-Yishay R, Yunger S, Brody Y, Shav-Tal Y. Dynamics of single mRNP nucleocytoplasmic transport and export through the nuclear pore in living cells. Nat Cell Biol. 2010 Jun12(6):543-52 p. 547 right columnPubMed ID20453848
Method To characterize in vivo export kinetics at the single mRNP (mRNA-protein complex) level, and to understand the relative temporal contribution of export to the total kinetics of nucleocytoplasmic translocation, researchers established a mammalian cell system harbouring stably integrated genes that enabled the tracking of single mRNPs from the time of transcription and during nuclear transport and export. Gene constructs containing different forms of the human dystrophin (Dys) cDNA fused to a fluorescent protein (green fluorescent protein (GFP) or Cerulean (Cer)) were generated. Active transcription sites and single mRNPs were detected by transient transfection with YFP–MS2-NLS (nuclear localization sequence).
Comments Human U2OS (osteosarcoma) cells. Note-from the single-particle tracking data researchers calculated an average translocation velocity of 0.65 ± 0.37 µm/sec (Fig. 5j, inset), thereby estimating an average time range of about 0.5 s or faster for translocation through the known pore size. A comparison of the MSD (mean square displacement) of diffusing nucleoplasmic or cytoplasmic mRNPs with the single mRNP export events (Fig. 5j) showed that mRNP movement through the pore was 15-fold faster than simple diffusion. Import of M9–transportin complexes occurred at speeds of 0.5 µm s-1 (Ribbeck et al., 2001 PMID 11250898), similar to researchers' measurements.
Entered by Uri M
ID 105652