Affiliation:
1. Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071-3944
Abstract
ABSTRACT
Actin-based motility (ABM) is a virulence mechanism exploited by invasive bacterial pathogens in the genera
Listeria
,
Shigella
, and
Rickettsia
. Due to experimental constraints imposed by the lack of genetic tools and their obligate intracellular nature, little is known about rickettsial ABM relative to
Listeria
and
Shigella
ABM systems. In this study, we directly compared the dynamics and behavior of ABM of
Rickettsia rickettsii
and
Listeria monocytogenes
. A time-lapse video of moving intracellular bacteria was obtained by laser-scanning confocal microscopy of infected Vero cells synthesizing β-actin coupled to green fluorescent protein (GFP). Analysis of time-lapse images demonstrated that
R. rickettsii
organisms move through the cell cytoplasm at an average rate of 4.8 ± 0.6 μm/min (mean ± standard deviation). This speed was 2.5 times slower than that of
L. monocytogenes
, which moved at an average rate of 12.0 ± 3.1 μm/min. Although rickettsiae moved more slowly, the actin filaments comprising the actin comet tail were significantly more stable, with an average half-life approximately three times that of
L. monocytogenes
(100.6 ± 19.2 s versus 33.0 ± 7.6 s, respectively). The actin tail associated with intracytoplasmic rickettsiae remained stationary in the cytoplasm as the organism moved forward. In contrast, actin tails of rickettsiae trapped within the nucleus displayed dramatic movements. The observed phenotypic differences between the ABM of
Listeria
and
Rickettsia
may indicate fundamental differences in the mechanisms of actin recruitment and polymerization.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
102 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献