TUTCRIS - Tampereen teknillinen yliopisto

TUTCRIS

Robustness of the process of nucleoid exclusion of protein aggregates in Escherichia coli

Tutkimustuotosvertaisarvioitu

Yksityiskohdat

AlkuperäiskieliEnglanti
Sivut898-906
Sivumäärä9
JulkaisuJournal of Bacteriology
Vuosikerta198
Numero6
DOI - pysyväislinkit
TilaJulkaistu - 2016
OKM-julkaisutyyppiA1 Alkuperäisartikkeli

Tiivistelmä

Escherichia coli segregates protein aggregates to the poles by nucleoid exclusion. Combined with cell divisions, this generates heterogeneous aggregate distributions in subsequent cell generations. We studied the robustness of this process with differing medium richness and antibiotics stress, which affect nucleoid size, using multimodal, time-lapse microscopy of live cells expressing both a fluorescently tagged chaperone (IbpA), which identifies in vivo the location of aggregates, and HupA-mCherry, a fluorescent variant of a nucleoid-associated protein. We find that the relative sizes of the nucleoid's major and minor axes change widely, in a positively correlated fashion, with medium richness and antibiotic stress. The aggregate's distribution along the major cell axis also changes between conditions and in agreement with the nucleoid exclusion phenomenon. Consequently, the fraction of aggregates at the midcell region prior to cell division differs between conditions, which will affect the degree of asymmetries in the partitioning of aggregates between cells of future generations. Finally, from the location of the peak of anisotropy in the aggregate displacement distribution, the nucleoid relative size, and the spatiotemporal aggregate distribution, we find that the exclusion of detectable aggregates from midcell is most pronounced in cells with mid-sized nucleoids, which are most common under optimal conditions. We conclude that the aggregate management mechanisms of E. coli are significantly robust but are not immune to stresses due to the tangible effect that these have on nucleoid size.

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