Viral RNA was extracted from each passage of virions selected at 51☌ (i.e., VS51), 53☌ (i.e., VS53), and 57☌ (i.e., VS57) ( 25). (B) Evolution of PV-1 under thermal selection. (A) Cartoon structure of the PV genome, showing the 5′ and 3′ UTRs flanking the open reading frame comprising the structural (P1) and nonstructural (P2 and P3) regions. Replication of the PV genome is mediated by the RdRp 3D pol ( 8) and primed by 3B within a membrane-bound complex that also includes 2B and 2C ( 9, 10) and 3A ( 11), whose roles are reviewed in reference 12.įIG 1 FIG 1 Identification of thermally selected mutations. The two nonstructural precursors, P2 and P3, are processed into 2A pro, 2B, and 2C and into 3A, 3B, 3C pro, and 3D pol, respectively, again by 3C pro/3CD pro ( 6, 7). Upon translation, the structural precursor protein, P1, is autocatalytically cleaved from the polyprotein by 2A pro ( 5), and P1 is further processed into VP1, VP3, and VP0 by 3C pro/3CD pro. Upon cell entry, the coding region is translated into a polyprotein precursor which is cleaved by viral proteases, 2A pro and 3C pro (or its precursor 3CD pro). 1A) comprises a coding region that is flanked at the 5′ and 3′ ends by untranslated regions (UTR) ( 4). Poliovirus (PV), which occurs as three serotypes, PV-1 to -3, is a picornavirus with a 7.5-kb positive-sense, single-stranded RNA genome enclosed within a 30-nm icosahedral capsid. The 2A pro mutations were further shown to slow the kinetics of viral polyprotein processing, and we suggest that this delay improves the correct folding of the mutant capsid precursor protein to permit virion assembly. However, they permitted a low level of assembly of infectious virions containing the otherwise lethal mutation in VP1. Introduction of these mutations into a wt infectious clone by site-directed mutagenesis considerably reduced replication. Both mutations were maintained throughout the selection process. Here we show, by sequencing beyond the capsid-coding region of the heat-selected virions, that two mutations had arisen within the coding region of the 2A protease. One of these mutations prevented virion assembly when introduced into a wild-type (wt) infectious clone. Two mutations in the VP1 protein acquired at an early stage were maintained throughout this selection procedure. In a previous study, we identified a number of mutations within the capsid-coding sequence of poliovirus (PV) that were established in the population during selection for greater thermostability by sequential treatment at progressively higher temperatures. Fulfilling these roles could place conflicting constraints on the innate abilities encoded within the protein sequences. These include self-assembly and maintaining stability under challenging environmental conditions, while retaining the conformational flexibility necessary to uncoat and deliver the viral genome into a host cell. Welcome to CLC Sequence Viewer 7.6.1 - a software package supporting your daily bioinformatics work.Virus capsid proteins must perform a number of roles. 1.5 When the program is installed: Getting started 1.5.1 Quick start. 1.2.5 Installation on Linux with an RPM-package 1.3 System requirements. 1.2.4 Installation on Linux with an installer. Introduction to CLC Sequence Viewer Contents 1.1 1.2Ĭontact information. 208ĭ Restriction enzymes database configuration 182 16 Phylogenetic treesġ6.1 Phylogenetic tree features. 180 15.4 Bioinformatics explained: Multiple alignments. 172 15 Sequence alignmentġ5.1 Create an alignment. 163 14.2 Restriction site analysis from the Toolbox. 160 14 Restriction site analysesġ4.1 Dynamic restriction sites. 157 13.5 Translation of DNA or RNA to protein. ![]() 155 13.3 Reverse complements of sequences. 153 13 Nucleotide analysesġ3.1 Convert DNA to RNA. 139 12 General sequence analysesġ2.1 Extract sequences. 137 10.5 Tools for linking sequence and structure. 129 10.4 Snapshots of the molecule visualization. 127 10.2 Viewing molecular structures in 3D. 123ġ0.1 Importing molecule structure files. Selecting which part of the view to print. When the program is installed: Getting started. ![]() QIAGEN Aarhus A/S Silkeborgvej 2 Prismet DK-8000 Aarhus C DenmarkĬontact information. CLC Sequence Viewer 7.6.1 Windows, Mac OS X and Linux SeptemThis software is for research purposes only.
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