scholarly journals Real-time analysis of single influenza virus replication complexes reveals large promoter-dependent differences in initiation dynamics

2019 ◽  
Author(s):  
Nicole C. Robb ◽  
Aartjan J.W. te Velthuis ◽  
Ervin Fodor ◽  
Achillefs N. Kapanidis
Keyword(s):  
Real Time ◽  
Virus Replication ◽  
Dynamic Equilibrium ◽  
Influenza Viruses ◽  
Time Analysis ◽  
Template Strand ◽  
Real Time Analysis ◽  
Influenza Virus Replication ◽  
Multiple Conformations

ABSTRACTThe viral RNA (vRNA) genome of influenza viruses is replicated by the RNA-dependent RNA polymerase (RNAP) via a complementary RNA (cRNA) intermediate. The vRNA promoter can adopt multiple conformations when bound by the RNAP. However, the dynamics, determinants, and biological role of these conformations are unknown; further, little is known about cRNA promoter conformations. To probe the RNA conformations adopted during initial replication, we monitored single, surface-immobilised vRNA and cRNA initiation complexes in real-time. Our results show that, while the 3’ terminus of the vRNA promoter exists in dynamic equilibrium between pre-initiation and initiation conformations, the cRNA promoter exhibited very limited dynamics. Two residues in the proximal 3’ region of the cRNA promoter (residues absent in the vRNA promoter) allowed the cRNA template strand to reach further into the active site, limiting promoter dynamics. Our results highlight promoter-dependent differences in influenza initiation mechanisms, and advance our understanding of virus replication.

scholarly journals Real-time analysis of single influenza virus replication complexes reveals large promoter-dependent differences in initiation dynamics

2019 ◽  
Vol 47 (12) ◽  
pp. 6466-6477 ◽  
Author(s):  
Nicole C Robb ◽  
Aartjan J W te Velthuis ◽  
Ervin Fodor ◽  
Achillefs N Kapanidis
Keyword(s):  
Real Time ◽  
Virus Replication ◽  
Dynamic Equilibrium ◽  
Influenza Viruses ◽  
Time Analysis ◽  
Template Strand ◽  
Real Time Analysis ◽  
Influenza Virus Replication ◽  
Multiple Conformations

AbstractThe viral RNA (vRNA) genome of influenza viruses is replicated by the RNA-dependent RNA polymerase (RNAP) via a complementary RNA (cRNA) intermediate. The vRNA promoter can adopt multiple conformations when bound by the RNAP. However, the dynamics, determinants, and biological role of these conformations are unknown; further, little is known about cRNA promoter conformations. To probe the RNA conformations adopted during initial replication, we monitored single, surface-immobilized vRNA and cRNA initiation complexes in real-time. Our results show that, while the 3′ terminus of the vRNA promoter exists in dynamic equilibrium between pre-initiation and initiation conformations, the cRNA promoter exhibited very limited dynamics. Two residues in the proximal 3′ region of the cRNA promoter (residues absent in the vRNA promoter) allowed the cRNA template strand to reach further into the active site, limiting promoter dynamics. Our results highlight promoter-dependent differences in influenza initiation mechanisms, and advance our understanding of virus replication.

A Novel Imaging Approach for Single-Cell Real-Time Analysis of Oncolytic Virus Replication and Efficacy in Cancer Cells

2021 ◽  
Vol 32 (3-4) ◽  
pp. 166-177
Author(s):  
Lorraine Quillien ◽  
Sokunthea Top ◽  
Sandrine Kappler-Gratias ◽  
Agathe Redouté ◽  
Nelson Dusetti ◽  
...  
Keyword(s):  
Single Cell ◽  
Cancer Cells ◽  
Real Time ◽  
Virus Replication ◽  
Oncolytic Virus ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Imaging Approach

scholarly journals N-Glycans attached to the stem domain of haemagglutinin efficiently regulate influenza A virus replication

2002 ◽  
Vol 83 (3) ◽  
pp. 601-609 ◽  
Author(s):  
Ralf Wagner ◽  
Dagmar Heuer ◽  
Thorsten Wolff ◽  
Astrid Herwig ◽  
Hans-Dieter Klenk
Keyword(s):  
Virus Replication ◽  
Influenza A ◽  
Influenza Viruses ◽  
Glycosylation Sites ◽  
Protein Mutants ◽  
Metastable Form ◽  
Influenza Virus Replication ◽  
Polymerase I ◽  
Ha Protein

The haemagglutinin (HA) protein of fowl plague virus A/FPV/Rostock/34 (H7N1) contains three N-linked oligosaccharide side chains in its stem domain. These stem glycans, which are attached to the Asn residues at positions 12, 28 and 478, are highly conserved throughout all HA protein sequences analysed to date. In a previous study, in which mutant HA proteins lacking individual stem glycosylation sites had been expressed from an SV-40 vector, it was shown that these glycans maintain the HA protein in the metastable form required for fusion activity. In the present study, the functional role of the stem N-glycans for virus replication was investigated using recombinant influenza viruses generated by an RNA polymerase I-based system. Studies in Madin–Darby canine kidney cells and embryonated chickens’ eggs revealed that the N-glycan at Asn12 is crucial for virus replication. In both culture systems, growth of virus lacking this glycan (mutant cg1) was completely blocked at 37 °C and inhibited at 33 °C. Loss of the glycan from Asn478 (mutant cg3) caused less striking, but still measurable, effects. Interestingly, it was not possible to generate mutant viruses containing the HA protein lacking the N-glycan at Asn28. It is concluded from this that the N-glycan at Asn28 is indispensable for the formation of replication-competent influenza viruses. When compared to viruses containing wild-type HA protein, mutants cg1 and cg3 showed a significantly decreased pH stability. Taken together, these data show that the HA stem glycans are potent regulators of influenza virus replication.

scholarly journals Correction: Real-time analysis of the role of Ca2+ in flagellar movement and motility in single sea urchin sperm

2005 ◽  
Vol 170 (7) ◽  
pp. 1171-1171
Author(s):  
Christopher D. Wood ◽  
Takuya Nishigaki ◽  
Toshiaki Furuta ◽  
Shoji A. Baba ◽  
Alberto Darszon
Keyword(s):  
Real Time ◽  
Sea Urchin ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Sea Urchin Sperm

(Invited) Elucidating the Role of Mo during the Passivation of Ni-Cr-Mo Alloys: Real Time Analysis of Elemental Dissolution and Surface Enrichment

2020 ◽  
Vol MA2020-02 (12) ◽  
pp. 1262-1262
Author(s):  
Xuejie Li ◽  
Jeffrey D. Henderson ◽  
David W. Shoesmith ◽  
James Noel ◽  
Kevin Ogle
Keyword(s):  
Real Time ◽  
Surface Enrichment ◽  
Time Analysis ◽  
Real Time Analysis

An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

1976 ◽  
Vol 34 ◽  
pp. 542-543
Author(s):  
R.P. Goehner ◽  
W.T. Hatfield ◽  
Prakash Rao
Keyword(s):  
Electron Diffraction ◽  
Real Time ◽  
Pattern Analysis ◽  
Flow Diagram ◽  
Hard Copy ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Transmission Electron ◽  
One Step ◽  
Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

scholarly journals Real-Time Analysis of Animal Feeding Behavior With a Low-Calculation-Power CPU

2020 ◽  
Vol 67 (4) ◽  
pp. 1197-1205 ◽  
Author(s):  
Yuki Totani ◽  
Susumu Kotani ◽  
Kei Odai ◽  
Etsuro Ito ◽  
Manabu Sakakibara
Keyword(s):  
Feeding Behavior ◽  
Real Time ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Animal Feeding

A threshold-based, real-time analysis in early detection of endpoint anomalies using SIEM expertise

2021 ◽  
Vol 2021 (4) ◽  
pp. 7-16
Author(s):  
Sivaraman Eswaran ◽  
Aruna Srinivasan ◽  
Prasad Honnavalli
Keyword(s):  
Early Detection ◽  
Real Time ◽  
Time Analysis ◽  
Real Time Analysis
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