It has been proposed that forces resulting from the physical exclusion of macromolecules from the bacterial nucleoid play a central role in organizing the bacterial cell, yet this proposal has not been quantitatively tested. To investigate this hypothesis, we mapped the generic motion of large protein complexes in the bacterial cytoplasm through quantitative analysis of thousands of complete cell-cycle trajectories of fluorescently tagged ectopic MS2-mRNA complexes. We find the motion of these complexes in the cytoplasm is strongly dependent on their spatial position along the long axis of the cell, and that their dynamics are consistent with a quantitative model that requires only nucleoid exclusion and membrane confinement. This analysis also reveals that the nucleoid increases the mobility of MS2-mRNA complexes, resulting in a fourfold increase in diffusion coefficients between regions of the lowest and highest nucleoid density. These data provide strong quantitative support for two modes of nucleoid action: the widely accepted mechanism of nucleoid exclusion in organizing the cell and a newly proposed mode, in which the nucleoid facilitates rapid motion throughout the cytoplasm.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4255419 | PMC |
| http://dx.doi.org/10.1016/j.bpj.2014.10.030 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Detection of mRNAs Anchored to the Nuclear Envelope During Export Inhibition in Living Cells.
Methods Mol Biol
April 2020
The Mina & Everard Goodman Faculty of Life Sciences and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel.
Export of mRNA transcripts from the cell nucleus is a complex and multistep process, regulated by various proteins and control mechanisms. Recent studies have demonstrated the rapid passage of mRNA-protein complexes (mRNPs) through the nuclear pore complex (NPC) as well as the ability to detect mRNPs stalled at the NPC during inhibition of the mRNA export process. In this chapter, we describe ways to block mRNA export and present an image analysis method to identify mRNPs stuck at the NPC during such blocks.
View Article and Find Full Text PDFTechniques for Single-Molecule mRNA Imaging in Living Cells.
Adv Exp Med Biol
September 2017
Center for Nervous System Disorders, Centers for Molecular Medicine, Stony Brook University, Stony Brook, NY, 11794, USA.
Typical measurement of macromolecules in a biological sample typically averages the result over all the cells or molecules within the sample, and while these types of measurements provide very useful information, they completely miss heterogeneity among the components within the sample that could be a very important aspect of the sample's function. These techniques are also limited in their ability to examine intracellular spatial orientation of molecular activity, which is often a critical component to the regulation of biological processes, particularly in cells with unique spatial relationships, such as neurons. This makes a strong case for single-cell and single-molecule analysis that allows similar novel insight into complex molecular machinery that would not be possible when pooling heterogeneous molecular states.
View Article and Find Full Text PDFCytoplasmic dynamics reveals two modes of nucleoid-dependent mobility.
Biophys J
December 2014
Department of Physics, University of Washington, Seattle, Washington; Department of Bioengineering, University of Washington, Seattle, Washington; Department of Microbiology, University of Washington, Seattle, Washington. Electronic address:
It has been proposed that forces resulting from the physical exclusion of macromolecules from the bacterial nucleoid play a central role in organizing the bacterial cell, yet this proposal has not been quantitatively tested. To investigate this hypothesis, we mapped the generic motion of large protein complexes in the bacterial cytoplasm through quantitative analysis of thousands of complete cell-cycle trajectories of fluorescently tagged ectopic MS2-mRNA complexes. We find the motion of these complexes in the cytoplasm is strongly dependent on their spatial position along the long axis of the cell, and that their dynamics are consistent with a quantitative model that requires only nucleoid exclusion and membrane confinement.
View Article and Find Full Text PDFA low number of SIC1 mRNA molecules ensures a low noise level in cell cycle progression of budding yeast.
Mol Biosyst
October 2011
Institute for Biology, Theoretical Biophysics, Humboldt University Berlin, Berlin, Germany.
The budding yeast genome comprises roughly 6000 genes generating a number of about 10 000 mRNA copies, which gives a general estimation of 1-2 mRNA copies generated per gene. What does this observation implicate for cellular processes and their regulation? Whether the number of mRNA molecules produced is important for setting the amount of proteins implicated in a particular function is at present unknown. In this context, we studied cell cycle control as one of the highly fine tuned processes that guarantee the precise timing of events essential for cell growth.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!