mRNA: Intranuclear Transport

Joan C Ritland Politz, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
Thoru Pederson, University of Massachusetts Medical School, Worcester, Massachusetts, USA

Published online: November 2010

DOI: 10.1002/9780470015902.a0005984.pub2

Abstract

Most genes are transcribed in the nuclear interior and the messenger ribonucleic acid (mRNA) must then move from its transcription site to the nuclear pores to be transported to the cytoplasm for translation. mRNAs interact with multiple proteins both during and after transcription, some of which help to determine their export competency. High‐resolution, live cell tracking studies show that when released from the transcription site, messenger ribonucleoprotein (mRNP) complexes move out into the nucleoplasm in all directions by simple diffusion. The mRNPs sometimes move discontinuously depending on obstacles they encounter and may be corralled in certain regions for a time, but overall, the nascent mRNPs rapidly distribute throughout the entire channel‐like interchromatin space. Export‐competent mRNPs then randomly encounter a nuclear pore and are captured for export to the cytoplasm.

Key Concepts:

  • mRNPs released from the transcription site move through the nucleoplasm primarily by diffusion.

  • Diffusing mRNPs can be corralled by encounters with obstacles such as chromatin.

  • Export‐competent mRNPs randomly encounter nuclear pores and are transported to the cytoplasm.

  • A minority of mRNAs are transcribed at the nuclear periphery and it is possible that these exit the nucleus through the nearest nuclear pore.

Keywords: transcription; mRNA; mRNP; intranuclear movement; nucleocytoplasmic transport; nuclear structure; mRNA export; diffusion

Figure 1.

Intranuclear localisation of uncaged FL–oligo(dT) compared to chromatin distribution. Cells were incubated sequentially with caged FL–oligo(dT) and Hoechst 33342 and three‐dimensional stacks in both (a,c,e) blue (Hoechst‐labelled chromatin) and (b,d,f) green (uncaged FL–oligo(dT)) channels were captured and deconvolved (Politz et al., ). (a, b) Raw and (c,d) deconvolved midsections show the distribution of Hoechst signal and uncaged FL–oligo(dT) signal in the same nucleus. (e,f) The same images as in (c,d) but high‐intensity regions of Hoechst signal were (e) outlined and (f) the outlines superimposed on the oligo(dT) image. (g) A colour encoded overlay in which the Hoechst signal is green and the oligo(dT) signal is red. (h) A plot (linescan) of the intensity (arbitrary units) versus pixel number for the Hoechst (green) and oligo(dT) (red) signals as they vary along a line across the middle of (g). For (a–g), each image is approximately 19×19 μm. Reproduced from Politz et al. , with permission from Elsevier.

Figure 2.

(a) First frame of a movie (green, mRNPs; red, red fluorescent protein (RFP)–tubulin). (b) Maximum projection (inverted). (c) Enlarged area (from red box in (b)) showing nucleoplasmic tracks (red arrows) and nucleoli (Nu). (d) Maximum projection of mRNPs imaged for two different periods in the same cell; red shows tracks from a 20‐s movie; for 1 min later, green shows tracks from another 20‐s movie. White spots represent one of the nuclear tracks. (e) Hoechst‐labelled chromatin (pseudo‐coloured red) and mRNPs (green) were imaged in three dimensions in a living cell. (f) Close‐up of a portion of the nucleus. (g,h) Three‐dimensional rendering showing the nuclear volumes and mRNPs between chromatin regions. (g) Slices through the centre of the nucleus are given, (h) gives a top‐down view. (i,j) Maximum time projection (i) showing that mRNPs (green; red, RFP–tubulin) do not travel through nucleoli (yellow arrows) seen in DIC (j). (k) Maximum time projection (imaged every 1 s for 80 s) of a 1/2‐Mini‐Dys+intron nucleus (inverted). (l) Enlargement of marked area in (k), showing a nucleoplasmic track used by several mRNPs. Bars, 10 μm. Reproduced from Mor et al. , with permission from Nature Publishing Group.

close

References

Akhtar A and Gasser SM (2007) The nuclear envelope and transcriptional control. Nature Reviews. Genetics 8(7): 507–517.

Blobel G (1985) Gene gating: a hypothesis. Proceedings of the National Academy of Sciences of the USA 82(24): 8527–8529.

Carmody SR and Wente SR (2009) mRNA nuclear export at a glance. Journal of Cell Science 122(12): 1933–1937.

Cremer T and Cremer C (2001) Chromosome territories, nuclear architecture and gene regulation in mammalian cells. Nature Reviews. Genetics 2(4): 292–301.

Dirks RW, Hattinger CM, Molenaar C and Snaar SP (1999) Synthesis, processing, and transport of RNA within the three‐dimensional context of the cell nucleus. Critical Reviews in Eukaryotic Gene Expression 9(3–4): 191–201.

Dworetzky SI and Feldherr CM (1988) Translocation of RNA‐coated gold particles through the nuclear pores of oocytes. Journal of Cell Biology 106(3): 575–584.

Iglesias N and Stutz F (2008) Regulation of mRNP dynamics along the export pathway. FEBS Letters 582(14): 1987–1996.

Janicki SM, Tsukamoto T, Salghetti SE et al. (2004) From silencing to gene expression: real‐time analysis in single cells. Cell 116(5): 683–698.

Kohler A and Hurt E (2007) Exporting RNA from the nucleus to the cytoplasm. Nature Reviews. Molecular Cell Biology 8(10): 761–773.

Kumaran RI, Thakar R and Spector DL (2008) Chromatin dynamics and gene positioning. Cell 132(6): 929–934.

Kylberg K, Bjork P, Fomproix N et al. (2010) Exclusion of mRNPs and ribosomal particles from a thin zone beneath the nuclear envelope revealed upon inhibition of transport. Experimental Cell Research 316(6): 1028–1038.

Mor A, Suliman S, Ben‐Yishay R et al. (2010) Dynamics of single mRNP nucleocytoplasmic transport and export through the nuclear pore in living cells. Nature Cell Biology 12(6): 543–552.

Politz JC, Browne E, Wolf D and Pederson T (1998) Intranuclear diffusion and hybridization state of oligonucleotides measured by fluorescence correlation spectroscopy in living cells. Proceedings of the National Academy of Sciences of the USA 95(11): 6043–6048.

Politz JC, Tuft RA, Pederson T and Singer RH (1999) Movement of nuclear poly(A) RNA throughout the interchromatin space in living cells. Current Biology 9(6): 285–291.

Politz JC, Tuft RA, Prasanth KV et al. (2006) Rapid, diffusional shuttling of poly(A) RNA between nuclear speckles and the nucleoplasm. Molecular Biology of the Cell 17(3): 1239–1249.

Ragoczy T, Bender MA, Telling A, Byron R and Groudine M (2006) The locus control region is required for association of the murine beta‐globin locus with engaged transcription factories during erythroid maturation. Genes & Development 20(11): 1447–1457.

Shav‐Tal Y, Darzacq X, Shenoy SM et al. (2004) Dynamics of single mRNPs in nuclei of living cells. Science 304(5678): 1797–1800.

Siebrasse JP, Veith R, Dobay A et al. (2008) Discontinuous movement of mRNP particles in nucleoplasmic regions devoid of chromatin. Proceedings of the National Academy of Sciences of the USA 105(51): 20291–20296.

Singh OP, Björkroth B, Masich S, Wieslander L and Daneholt B (1999) The intranuclear movement of Balbiani ring premessenger ribonucleoprotein particles. Experimental Cell Research 251(1): 135–146.

Sutherland H and Bickmore WA (2009) Transcription factories: gene expression in unions? Nature Reviews. Genetics 10(7): 457–466.

Vargas DY, Raj A, Marras SA, Kramer FR and Tyagi S (2005) Mechanism of mRNA transport in the nucleus. Proceedings of the National Academy of Sciences of the USA 102(47): 17008–17013.

Zachar Z, Kramer J, Mims IP and Bingham PM (1993) Evidence for channeled diffusion of pre‐mRNAs during nuclear RNA transport in metazoans. Journal of Cell Biology 121(4): 729–742.

Zhao J, Jin S‐B, Björkroth B, Wieslander L and Daneholt B (2002) The mRNA export factor Dbp5 is associated with Balbiani ring mRNP from gene to cytoplasm. EMBO Journal 21(5): 1177–1187.

Further Reading

van den Bogaard PT and Tyagi S (2009) Using molecular beacons to study dispersal of mRNPs from the gene locus. Methods in Molecular Biology 464: 91–103.

Daneholt B (2001) Assembly and transport of a premessenger RNP particle. Proceedings of the National Academy of Sciences of the USA 98(13): 7012–7017.

Jackson DA, Pombo A and Iborra F (2000) The balance sheet for transcription: an analysis of nuclear RNA metabolism in mammalian cells. FASEB Journal 14(2): 242–252.

Moore MJ and Proudfoot NJ (2009) Pre‐mRNA processing reaches back to transcription and ahead to translation. Cell 136(4): 688–700.

Park HY, Buxbaum AR and Singer RH (2010) Single mRNA tracking in live cells. In: Methods in Enzymology: Single Molecule Tools, Pt A: Fluorescence Based Approaches, vol 472, pp. 387–406. San Diego: Elsevier Academic Press Inc.

Pederson T (2010) The nucleus introduced. In: Spector D and Misteli T (eds) Cold Spring Harbor Perspectives in Biology. New York: Cold Spring Harbor Laboratory Press.

Politz JC and Pederson T (2000) Movement of mRNA from transcription site to nuclear pores. Journal of Structural Biology 129(2–3): 252–257.

Schuss Z, Singer A and Holcman D (2007) The narrow escape problem for diffusion in cellular microdomains. Proceedings of the National Academy of Sciences of the USA 104(41): 16098–16103.

Vinciguerra P and Stutz F (2004) mRNA export: an assembly line from genes to nuclear pores. Current Opinion in Cell Biology 16(3): 285–292.

Wachsmuth M, Waldeck W and Langowski J (2000) Anomalous diffusion of fluorescent probes inside living cell nuclei investigated by spatially resolved fluorescence correlation spectroscopy. Journal of Molecular Biology 298(4): 677–689.

Related Sub-Topics:

Nucleic Acids: Structure, Function, Metabolism | Basic Cell Biology, Protein, RNA and DNA | RNA Structure and Function | Cellular Transport | Molecular Transport
Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

Article Title: mRNA: Intranuclear Transport
 
How to Cite close
Politz, Joan C Ritland, and Pederson, Thoru(Nov 2010) mRNA: Intranuclear Transport. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0005984.pub2]