TY - JOUR
T1 - Induction of the Yersinia Type 3 Secretion System as an All-or-None Phenomenon
AU - Wiley, David J.
AU - Rosqvist, Roland
AU - Schesser, Kurt
N1 - Funding Information:
We thank George Munson, Gregory Plano, Chaitanya Jain, Ken Fields, and two anonymous reviewers for thoughtful suggestions on the manuscript, and Christopher J. DaFonseca for assistance in developing the foundation experiments. This work was supported, in part, by grants from the Miller School of Medicine, University of Miami and from Public Health Service grant AI53459 from the National Institute of Allergy and Infectious Diseases.
PY - 2007/10/12
Y1 - 2007/10/12
N2 - Pathogenic Yersinia spp. possess a protein secretion system, designated as type 3, that plays a clear role in promoting their survival vis-à-vis the macrophage. Inductive expression of the Yersinia type 3 secretion system (T3SS), triggered either by host cell contact, or, in the absence of host cells, by a reduction in extracellular calcium ion levels, is accompanied by a withdrawal from the bacterial division cycle. Here, we analyzed Ca2+-dependent induction of the T3SS at the single-cell level to understand how Yersinia coordinates pro-survival and growth-related activities. We utilized a novel high-throughput quantitative microscopy approach as well as flow cytometry to determine how Ca2+ levels, T3SS expression, and cellular division are interrelated. Our analysis showed that there is a high degree of homogeneity in terms of T3SS expression levels among a population of Y. pseudotuberculosis cells following the removal of Ca2+, and that T3SS expression appears to be independent of the cellular division cycle. Unexpectedly, our analysis showed that Ca2+ levels are inversely related to the initiation of inductive T3SS expression, and not to the intensity of activation once initiated, thus providing a basis for the seemingly graded response of T3SS activation observed in bulk-level analyses. The properties of the system described here display both similarities to and differences from that of the lac operon first described 50 years ago by Novick and Weiner.
AB - Pathogenic Yersinia spp. possess a protein secretion system, designated as type 3, that plays a clear role in promoting their survival vis-à-vis the macrophage. Inductive expression of the Yersinia type 3 secretion system (T3SS), triggered either by host cell contact, or, in the absence of host cells, by a reduction in extracellular calcium ion levels, is accompanied by a withdrawal from the bacterial division cycle. Here, we analyzed Ca2+-dependent induction of the T3SS at the single-cell level to understand how Yersinia coordinates pro-survival and growth-related activities. We utilized a novel high-throughput quantitative microscopy approach as well as flow cytometry to determine how Ca2+ levels, T3SS expression, and cellular division are interrelated. Our analysis showed that there is a high degree of homogeneity in terms of T3SS expression levels among a population of Y. pseudotuberculosis cells following the removal of Ca2+, and that T3SS expression appears to be independent of the cellular division cycle. Unexpectedly, our analysis showed that Ca2+ levels are inversely related to the initiation of inductive T3SS expression, and not to the intensity of activation once initiated, thus providing a basis for the seemingly graded response of T3SS activation observed in bulk-level analyses. The properties of the system described here display both similarities to and differences from that of the lac operon first described 50 years ago by Novick and Weiner.
KW - gene expression
KW - induction
KW - type 3 secretion
KW - Yersinia
KW - Yops
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U2 - 10.1016/j.jmb.2007.07.077
DO - 10.1016/j.jmb.2007.07.077
M3 - Article
C2 - 17825321
AN - SCOPUS:34548561946
VL - 373
SP - 27
EP - 37
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 1
ER -