Viral mutation accelerated by nitric oxide production during infection in vivo.
Nitric oxide (NO), superoxide (O(2)(-)), and their reaction product peroxynitrite (ONOO(-)) are generated in excess during a host's response against viral infection, and contribute to viral pathogenesis by promoting oxidative stress and tissue injury. Here we demonstrate that NO and peroxynitrite greatly accelerates the mutation of Sendai virus (SeV), a nonsegmented negative-strand RNA virus, by using green fluorescent protein (GFP) inserted into and expressed by a recombinant SeV (GFP-SeV) as an indicator for mutation. GFP-SeV mutation frequencies were much higher in the wild-type mice than in those lacking inducible NO synthase, suggesting that mutation of the virus in vivo is NO dependent. High levels of NO and NO-mediated oxidative stress were induced by GFP-SeV infection in the lung of the wild-type mice, but not in the iNOS-deficient mice, as evidenced by electron spin resonance spectroscopy and immunohistochemical analysis for nitrotyrosine formation as well as histopathological examination. Furthermore, peroxynitrite, an NO-derived reactive nitrogen intermediate, enhanced viral mutation in vitro. These results indicate that the oxidative stress induced by NO produced during the natural course of viral infection increases mutation, expands the quasispecies spectrum, and facilitates evolution of RNA viruses.
Akaike
T
T
Departments of Microbiology and Medicine I, Kumamoto University School of Medicine, Japan. takakaik@gpo.kumamoto-u.ac.jp
Fujii
S
S
Kato
A
A
Yoshitake
J
J
Miyamoto
Y
Y
Sawa
T
T
Okamoto
S
S
Suga
M
M
Asakawa
M
M
Nagai
Y
Y
Maeda
H
H
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D018384:Oxidative Stress; D011024:Pneumonia, Viral / Q000209:etiology / Q000378:metabolism / Q000821:virology; D018108:Respirovirus / Q000235:genetics* / Q000472:pathogenicity*; D010253:Respirovirus Infections / Q000209:etiology* / Q000378:metabolism / Q000821:virology
D017931:DNA Primers; D004279:DNA, Viral; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse