Single mRNA molecules demonstrate probabilistic movement in living mammalian cells.
Cytoplasmic mRNA movements ultimately determine the spatial distribution of protein synthesis. Although some mRNAs are compartmentalized in cytoplasmic regions, most mRNAs, such as housekeeping mRNAs or the poly-adenylated mRNA population, are believed to be distributed throughout the cytoplasm. The general mechanism by which all mRNAs may move, and how this may be related to localization, is unknown. Here, we report a method to visualize single mRNA molecules in living mammalian cells, and we report that, regardless of any specific cytoplasmic distribution, individual mRNA molecules exhibit rapid and directional movements on microtubules. Importantly, the beta-actin mRNA zipcode increased both the frequency and length of these movements, providing a common mechanistic basis for both localized and nonlocalized mRNAs. Disruption of the cytoskeleton with drugs showed that microtubules and microfilaments are involved in the types of mRNA movements we have observed, which included complete immobility and corralled and nonrestricted diffusion. Individual mRNA molecules switched frequently among these movements, suggesting that mRNAs undergo continuous cycles of anchoring, diffusion, and active transport.
Fusco
Dahlene
D
Departments of Anatomy and Structural Biology and Cell Biology, Albert Einstein College of Medicine Bronx, New York 10461.
Accornero
Nathalie
N
Institut de Genetique Moleculaire de Montpellier-CNRS UMR 5535 IFR 24 1919 route de Mende 34293 Montpellier Cedex 5 France.
Lavoie
Brigitte
B
NINDS/NIH Molecular Plasticity Section Bethesda, Maryland 20892.
Shenoy
Shailesh M
SM
Departments of Anatomy and Structural Biology and Cell Biology, Albert Einstein College of Medicine Bronx, New York 10461.
Blanchard
Jean-Marie
JM
Institut de Genetique Moleculaire de Montpellier-CNRS UMR 5535 IFR 24 1919 route de Mende 34293 Montpellier Cedex 5 France.
Singer
Robert H
RH
Departments of Anatomy and Structural Biology and Cell Biology, Albert Einstein College of Medicine Bronx, New York 10461.
Bertrand
Edouard
E
Institut de Genetique Moleculaire de Montpellier-CNRS UMR 5535 IFR 24 1919 route de Mende 34293 Montpellier Cedex 5 France.
D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000235:genetics; D000818:Animals; D019556:COS Cells; D003593:Cytoplasm / Q000378:metabolism; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D007763:Lac Operon; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D008954:Models, Biological; D015233:Models, Statistical; D009068:Movement; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D000199:Actins; D008164:Luminescent Proteins; D011506:Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins