St. Louis encephalitis virus: An ultrastructural study of infection in a mosquito vector

Whitfield, Sylvia G.; Murphy, Frederick A.; Sudia, W. D.

doi:10.1016/0042-6822(73)90288-2

Cited by 79 publications

(43 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most of these observations are consistent in the points that dengue virion morphogenesis takes place in close relationship with the intracellular membranes, especially R E R membranes, and that mature virions are observed mostly in the eisternae of these membranous structures. Such fundamental characteristics of virion morphogenesis appear to be common features in ftavivirus infected vertrebrate cells (1,2,3,4,5,6,7,10,11,18,23,26,29,31,34,35,36,39,41,47,49) or mosquito cells (14,21,48). Our observations in dengue infected A. albopictus cells are also consistent with these points.…”

Section: Discussionsupporting

confidence: 89%

“…Such remarkable vesiculotubular structures were not observed in dengue infected BHK21 cells, but were reported in Culex pipiens salivary glands infected with St. Louis encephalitis virus (48). Vesicular structures of similar appearance but fewer in number were also observed in distended cisternae of RER in dengue infected mouse brains (43,44) or LLC-MK2 cells (8,12,45).…”

Section: Discussionmentioning

confidence: 85%

See 1 more Smart Citation

Electron microscopic observations onAedes albopictus cells infected with dengue viruses

Igarashi

Fukai

1979

Archives of Virology

View full text Add to dashboard Cite

SummaryIn dengue virus infected Aedes albopictus cells, electron-dense particles, larger than single ribosomes, were arranged on the cytoplasmic sides of rough endoplasmic reticulum (I~ER) membranes. Mature virions 40---45 nm in diameter as well as vesieulotubular structures 50--120 nm in diameter appeared in enlarged cisternae of I~EI~ filled with fine granular substance. Many of the mature virions and somewhat degenerated vesiculotubular structures remained to be enclosed in membranous structures presumably derived from I~.EI~, even after degeneration of infected cells. The findings suggest that development of dengue viruses in cultured A. albopictus cells takes place in close relationship with the activated membranes of RELY.Other morphological changes observed in dengue infected A. albopictus cells were 1. electron-dense "double-track structures" in areas of virion morphogenesis, 2. fine crystalline structures in type-2 dengue infected cells, and 3. aggregates of nucleoid structures, in cells persistently infected with type 2 dengue virus. The implication and nature of these structures in relation to virion morphogenesis remain to be investigated.

show abstract

Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 85%

Electron microscopic observations onAedes albopictus cells infected with dengue viruses

Igarashi

Fukai

1979

Archives of Virology

View full text Add to dashboard Cite

show abstract

“…In our study, we found no direct correlation between the expression of sfRNA1 and the abundance of (v)siRNAs produced in vivo. We cannot formally exclude the possibility that sfRNA1 facilitates WNV replication by RNAi suppression at an early stage so that later more viral dsRNA can be processed into vsiRNA, but the The effect of sfRNA on midgut infection most likely occurs during initial infection, which takes place in a small number of cells (54). This "single-cell" interaction requires very high-resolution sequence data to detect potential RNAi suppression by sfRNA, which can explain why we did not find this correlation in our experiments.…”

Section: Discussionmentioning

confidence: 99%

Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes

Göertz

Fros

Miesen

et al. 2016

J Virol

114

163

View full text Add to dashboard Cite

Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5=-3= exoribonuclease XRN1/Pacman on conserved RNA structures in the 3= untranslated region (UTR) of the viral genomic RNA. sfRNA production is conserved in insect-specific, mosquito-borne, and tick-borne flaviviruses and flaviviruses with no known vector, suggesting a pivotal role for sfRNA in the flavivirus life cycle. Here, we investigated the function of sfRNA during WNV infection of Culex pipiens mosquitoes and evaluated its role in determining vector competence. An sfRNA1-deficient WNV was generated that displayed growth kinetics similar to those of wild-type WNV in both RNA interference (RNAi)-competent and -compromised mosquito cell lines. Small-RNA deep sequencing of WNV-infected mosquitoes indicated an active small interfering RNA (siRNA)-based antiviral response for both the wild-type and sfRNA1-deficient viruses. Additionally, we provide the first evidence that sfRNA is an RNAi substrate in vivo. Two reproducible small-RNA hot spots within the 3= UTR/sfRNA of the wild-type virus mapped to RNA stem-loops SL-III and 3= SL, which stick out of the three-dimensional (3D) sfRNA structure model. Importantly, we demonstrate that sfRNA-deficient WNV displays significantly decreased infection and transmission rates in vivo when administered via the blood meal. Finally, we show that transmission and infection rates are not affected by sfRNA after intrathoracic injection, thereby identifying sfRNA as a key driver to overcome the mosquito midgut infection barrier. This is the first report to describe a key biological function of sfRNA for flavivirus infection of the arthropod vector, providing an explanation for the strict conservation of sfRNA production. IMPORTANCEUnderstanding the flavivirus transmission cycle is important to identify novel targets to interfere with disease and to aid development of virus control strategies. Flaviviruses produce an abundant noncoding viral RNA called sfRNA in both arthropod and mammalian cells. To evaluate the role of sfRNA in flavivirus transmission, we infected mosquitoes with the flavivirus West Nile virus and an sfRNA-deficient mutant West Nile virus. We demonstrate that sfRNA determines the infection and transmission rates of West Nile virus in Culex pipiens mosquitoes. Comparison of infection via the blood meal versus intrathoracic injection, which bypasses the midgut, revealed that sfRNA is important to overcome the mosquito midgut barrier. We also show that sfRNA is processed by the antiviral RNA interference machinery in mosquitoes. This is the first report to describe a pivotal biological function of sfRNA in arthropods. The results explain why sfRNA production is evolutionarily conserved. Viruses from the genus Flavivirus (family Flaviviridae), such as the highly pathogenic dengue virus (DENV...

show abstract

“…Complete formation of the peritrophic matrix takes 12 to 30 h (44); therefore, it does not serve as a formidable barrier to filarial worms or viruses that generally enter or migrate through the midgut epithelium within a few hours, although it has been suggested that viruses that fail to exit the blood bolus within a few hours become trapped by the developing peritrophic matrix (259). Differential infectivity of Plasmodium to different mosquitoes has been attributed to differences in the rate of peritrophic matrix formation and ookinete development (189,191), but in general, Plasmodium parasites have developed specific mechanisms for traversing the peritrophic matrix following ookinete formation.…”

Section: Midgutmentioning

confidence: 99%

Genetics of Mosquito Vector Competence

Beerntsen

James

Christensen

2000

Microbiol Mol Biol Rev

343

278

View full text Add to dashboard Cite

SUMMARY Mosquito-borne diseases are responsible for significant human morbidity and mortality throughout the world. Efforts to control mosquito-borne diseases have been impeded, in part, by the development of drug-resistant parasites, insecticide-resistant mosquitoes, and environmental concerns over the application of insecticides. Therefore, there is a need to develop novel disease control strategies that can complement or replace existing control methods. One such strategy is to generate pathogen-resistant mosquitoes from those that are susceptible. To this end, efforts have focused on isolating and characterizing genes that influence mosquito vector competence. It has been known for over 70 years that there is a genetic basis for the susceptibility of mosquitoes to parasites, but until the advent of powerful molecular biological tools and protocols, it was difficult to assess the interactions of pathogens with their host tissues within the mosquito at a molecular level. Moreover, it has been only recently that the molecular mechanisms responsible for pathogen destruction, such as melanotic encapsulation and immune peptide production, have been investigated. The molecular characterization of genes that influence vector competence is becoming routine, and with the development of the Sindbis virus transducing system, potential antipathogen genes now can be introduced into the mosquito and their effect on parasite development can be assessed in vivo. With the recent successes in the field of mosquito germ line transformation, it seems likely that the generation of a pathogen-resistant mosquito population from a susceptible population soon will become a reality.

show abstract

St. Louis encephalitis virus: An ultrastructural study of infection in a mosquito vector

Cited by 79 publications

References 22 publications

Electron microscopic observations onAedes albopictus cells infected with dengue viruses

Electron microscopic observations onAedes albopictus cells infected with dengue viruses

Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes

Genetics of Mosquito Vector Competence

Contact Info

Product

Resources

About