Document Detail


Time-dependent Effects of Transcription- and Translation-halting Drugs on the Spatial Distributions of the E. coli Chromosome and Ribosomes.
MedLine Citation:
PMID:  25250841     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Previously observed effects of rifampicin and chloramphenicol indicate that transcription and translation activity strongly affect the coarse spatial organization of the bacterial cytoplasm. Single-cell, time-resolved, quantitative imaging of chromosome and ribosome spatial distributions and ribosome diffusion in live E. coli provides insight into the underlying mechanisms. Monte Carlo simulations of model DNA-ribosome mixtures support a novel nucleoid-ribosome mixing hypothesis. In normal conditions, 70S-polysomes and the chromosomal DNA segregate, while 30S and 50S ribosomal subunits are able to penetrate the nucleoids. Growth conditions and drug treatments determine the partitioning of ribosomes into 70S-polysomes vs free 30S and 50S subunits. Entropic and excluded volume effects then dictate the resulting chromosome and ribosome spatial distributions. Direct observation of radial contraction of the nucleoids 0-5 min after treatment with either transcription- or translation-halting drugs supports the hypothesis that simultaneous transcription, translation, and insertion of proteins into the membrane ("transertion") exerts an expanding force on the chromosomal DNA. Breaking of the DNA-RNA polymerase-mRNA-ribosome-membrane chain in either of two places causes similar nucleoid contraction on a similar timescale. We suggest that chromosomal expansion due to transertion enables co-transcriptional translation throughout the nucleoids.
Authors:
Somenath Bakshi; Heejun Choi; Jagannath Mondal; James C Weisshaar
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-9-24
Journal Detail:
Title:  Molecular microbiology     Volume:  -     ISSN:  1365-2958     ISO Abbreviation:  Mol. Microbiol.     Publication Date:  2014 Sep 
Date Detail:
Created Date:  2014-9-24     Completed Date:  -     Revised Date:  2014-9-25    
Medline Journal Info:
Nlm Unique ID:  8712028     Medline TA:  Mol Microbiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
This article is protected by copyright. All rights reserved.
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