On the infectivity of the Sindbis virus nucleocapsid

1970 ◽  
Vol 16 (12) ◽  
pp. 1273-1283 ◽  
Author(s):  
P. Dobos ◽  
P. Faulkner
Keyword(s):  
Infected Cell ◽  
Viral Replication ◽  
Cell Cultures ◽  
Sindbis Virus ◽  
Envelope Proteins ◽  
Intact Virus

The nucleocapsid fraction derived either from Sindbis virions or from infected cell cultures was studied with respect to its ability to adsorb to susceptible cells as well as to initiate stages in viral replication. Neither preparation was adsorbed to BHK 21 cells under conditions where virion adsorption could be demonstrated. In addition parental RNA from virions was shown to be converted to an RNAase-resistant 16–20 S form, whereas no evidence for the penetration and conversion of RNA present in viral cores was observed. These studies emphasize the role of envelope proteins in facilitating entry of intact virus into susceptible cells.

scholarly journals Role of Sindbis Virus Capsid Protein Region II in Nucleocapsid Core Assembly and Encapsidation of Genomic RNA

2008 ◽  
Vol 82 (9) ◽  
pp. 4461-4470 ◽  
Author(s):  
Ranjit Warrier ◽  
Benjamin R. Linger ◽  
Barbara L. Golden ◽  
Richard J. Kuhn
Keyword(s):  
Amino Acids ◽  
Capsid Protein ◽  
Sindbis Virus ◽  
Rna Virus ◽  
Genomic Rna ◽  
Viral Glycoproteins ◽  
Infected Cells ◽  
Viral Genomic Rna ◽  
Region Ii

ABSTRACT Sindbis virus is an enveloped positive-sense RNA virus in the alphavirus genus. The nucleocapsid core contains the genomic RNA surrounded by 240 copies of a single capsid protein. The capsid protein is multifunctional, and its roles include acting as a protease, controlling the specificity of RNA that is encapsidated into nucleocapsid cores, and interacting with viral glycoproteins to promote the budding of mature virus and the release of the genomic RNA into the newly infected cell. The region comprising amino acids 81 to 113 was previously implicated in two processes, the encapsidation of the viral genomic RNA and the stable accumulation of nucleocapsid cores in the cytoplasm of infected cells. In the present study, specific amino acids within this region responsible for the encapsidation of the genomic RNA have been identified. The region that is responsible for nucleocapsid core accumulation has considerable overlap with the region that controls encapsidation specificity.

The role of calcium in the increase in flocculence of yeast growing in the presence of copper

1965 ◽  
Vol 162 (989) ◽  
pp. 555-566 ◽  
Keyword(s):  
Liquid Medium ◽  
Cell Cultures ◽  
Chloride Solution ◽  
Liquid Copper ◽  
Acquired Resistance ◽  
Calcium Chloride Solution ◽  
Copper Resistance ◽  
Liquid Cultures ◽  
Selection Of

Growth in the presence of inhibitory concentrations of copper enhances the tendency of yeast to flocculate. Many yeasts will not flocculate unless calcium is included in the growth medium and Guinness strain 522 used in the present work required a relatively large amount. Single cell cultures may undergo variation during subculture, resulting in the production of a large number of variants (Chester 1963). The cells of these variants differ considerably in their ability to adhere together. Flocculation variants of strain 522 differed among themselves in the amount of calcium necessary for flocculation, the most flocculent variants requiring least calcium. Washed cells of the more flocculent yeasts removed more calcium from a calcium chloride solution than did those with lesser powers of adhesion. In a copper medium con­taining calcium the more flocculent variants replaced the less flocculent. Calcium protected cells from copper and the more flocculent variants enjoyed most protection. All variants acquired resistance to copper during growth in the copper medium. Despite the selection of the more flocculent yeasts during growth in liquid medium, their copper resistance was less than that of the less flocculent yeasts. When calcium was added to the liquid copper medium, cultures developed less resistance. It is concluded that the less flocculent cells, having less protection by calcium, were exposed to what was effectively a greater concentration of copper and therefore became more resistant. This greater resistance did not enable these cells to compete with the flocculent cells in liquid cultures.

Possible role of mitochondria in posttetanic potentiation of GABAergic synaptic transmission in rat neocortical cell cultures

Synapse ◽  
2005 ◽  
Vol 58 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Maksim V. Storozhuk ◽  
Svetlana Y. Ivanova ◽  
Pavel M. Balaban ◽  
Platon G. Kostyuk
Keyword(s):  
Synaptic Transmission ◽  
Cell Cultures ◽  
Posttetanic Potentiation ◽  
Gabaergic Synaptic Transmission

Enterovirus 71 induces integrin β1/EGFR-Rac1-dependent oxidative stress in SK-N-SH cells: Role of HO-1/CO in viral replication

2011 ◽  
Vol 226 (12) ◽  
pp. 3316-3329 ◽  
Author(s):  
Wei-Hsuan Tung ◽  
Hsi-Lung Hsieh ◽  
I-Ta Lee ◽  
Chuen-Mao Yang
Keyword(s):  
Oxidative Stress ◽  
Viral Replication ◽  
Enterovirus 71 ◽  
Integrin Β1

Evaluation of Photobiogoverning Role of Blue Light Irradiation on Viral Replication

2021 ◽  
Author(s):  
Phil‐Sun Oh ◽  
Kyung Won Kang ◽  
Seung Rok Ryu ◽  
SeokTae Lim ◽  
Myung‐Hee Sohn ◽  
...  
Keyword(s):  
Viral Replication ◽  
Blue Light ◽  
Light Irradiation

scholarly journals Hepatitis C Virus Subverts Human Choline Kinase-α To Bridge Phosphatidylinositol-4-Kinase IIIα (PI4KIIIα) and NS5A and Upregulates PI4KIIIα Activation, Thereby Promoting the Translocation of the Ternary Complex to the Endoplasmic Reticulum for Viral Replication

2017 ◽  
Vol 91 (16) ◽  
Author(s):  
Mun-Teng Wong ◽  
Steve S. Chen
Keyword(s):  
Endoplasmic Reticulum ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Viral Replication ◽  
Ternary Complex ◽  
Choline Kinase ◽  
Replication Complex ◽  
Viral Replication Complex ◽  
Phosphatidylinositol 4

ABSTRACT In this study, we elucidated the mechanism by which human choline kinase-α (hCKα) interacts with nonstructural protein 5A (NS5A) and phosphatidylinositol-4-kinase IIIα (PI4KIIIα), the lipid kinase crucial for maintaining the integrity of virus-induced membranous webs, and modulates hepatitis C virus (HCV) replication. hCKα activity positively modulated phosphatidylinositol-4-phosphate (PI4P) levels in HCV-expressing cells, and hCKα-mediated PI4P accumulation was abolished by AL-9, a PI4KIIIα-specific inhibitor. hCKα colocalized with NS5A and PI4KIIIα or PI4P; NS5A expression increased hCKα and PI4KIIIα colocalization; and hCKα formed a ternary complex with PI4KIIIα and NS5A, supporting the functional interplay of hCKα with PI4KIIIα and NS5A. PI4KIIIα inactivation by AL-9 or hCKα inactivation by CK37, a specific hCKα inhibitor, impaired the endoplasmic reticulum (ER) localization and colocalization of these three molecules. Interestingly, hCKα knockdown or inactivation inhibited PI4KIIIα-NS5A binding. In an in vitro PI4KIIIα activity assay, hCKα activity slightly increased PI4KIIIα basal activity but greatly augmented NS5A-induced PI4KIIIα activity, supporting the essential role of ternary complex formation in robust PI4KIIIα activation. Concurring with the upregulation of PI4P production and viral replication, overexpression of active hCKα-R (but not the D288A mutant) restored PI4KIIIα and NS5A translocation to the ER in hCKα stable knockdown cells. Furthermore, active PI4KIIIα overexpression restored PI4P production, PI4KIIIα and NS5A translocation to the ER, and viral replication in CK37-treated cells. Based on our results, hCKα functions as an indispensable regulator that bridges PI4KIIIα and NS5A and potentiates NS5A-stimulated PI4KIIIα activity, which then facilitates the targeting of the ternary complex to the ER for viral replication. IMPORTANCE The mechanisms by which hCKα activity modulates the transport of the hCKα-NS5A complex to the ER are not understood. In the present study, we investigated how hCKα interacts with PI4KIIIα (a key element that maintains the integrity of the “membranous web” structure) and NS5A to regulate viral replication. We demonstrated that HCV hijacks hCKα to bridge PI4KIIIα and NS5A, forming a ternary complex, which then stimulates PI4KIIIα activity to produce PI4P. Pronounced PI4P synthesis then redirects the translocation of the ternary complex to the ER-derived, PI4P-enriched membrane for assembly of the viral replication complex and viral replication. Our study provides novel insights into the indispensable modulatory role of hCKα in the recruitment of PI4KIIIα to NS5A and in NS5A-stimulated PI4P production and reveals a new perspective for understanding the impact of profound PI4KIIIα activation on the targeting of PI4KIIIα and NS5A to the PI4P-enriched membrane for viral replication complex formation.

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