{"title":"Recombination and Other Genomic Rearrangements in Picornaviruses","authors":"Vadim I. Agol","doi":"10.1006/smvy.1997.0112","DOIUrl":"10.1006/smvy.1997.0112","url":null,"abstract":"<div><p>The available data on rearrangements (recombinations, deletions, and insertions) of picornavirus genomes fit the replicative template switch model postulating that an incomplete nascent minus RNA strand leaves the template and resumes its synthesis on another template (or another locus of the original template). The nascent strand dissociation is believed to be facilitated by the elongation pausing caused by secondary structure elements or nucleotide misincorporations. Rearrangements may involve (nearly) identical or completely dissimilar pairs of parting and anchoring sites. Rearrangements contribute to both conservation and variation of the picornaviral genomes.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"8 2","pages":"Pages 77-84"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1997.0112","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51139582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Pseudoknots: A Vital Feature in Viral RNA","authors":"Birgit A.L.M. Deiman, Cornelis W.A. Pleij","doi":"10.1006/smvy.1997.0119","DOIUrl":"10.1006/smvy.1997.0119","url":null,"abstract":"<div><p>The pseudoknot or “base-paired loop region” is a widespread structural motif in all kinds of viral RNAs. Detailed structures of hairpin-type pseudoknots, obtained by NMR, are now emerging, but it is still not clear which structural features are responsible for the different functions in processes like translation and replication. Especially noncoding regions are rich sources of pseudoknot structures, where they occur in domains like IRES elements and tRNA-like structures. But also its role in coding regions like in ribosomal -1 frameshifting and read-through is well established, although the precise mechanism of interference with the translational mechanism remains unknown.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"8 3","pages":"Pages 166-175"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1997.0119","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51139940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"cis-Acting Signals on the RNAs of Hepatitis Delta Virus","authors":"John M. Taylor","doi":"10.1006/smvy.1997.0124","DOIUrl":"10.1006/smvy.1997.0124","url":null,"abstract":"<div><p>The replication of the genomic RNA of hepatitis delta virus involves RNA-directed RNA synthesis and various forms of RNA processing, including ribozyme cleavage, polyadenylation, and RNA editing. The purpose of this article is to evaluate the evidence concerning eight sequence elements that may contribute to the direction of these different events.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"8 3","pages":"Pages 212-220"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1997.0124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51141734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hans E. Johansson , Lars Liljas , Olke C. Uhlenbeck
{"title":"RNA Recognition by the MS2 Phage Coat Protein","authors":"Hans E. Johansson , Lars Liljas , Olke C. Uhlenbeck","doi":"10.1006/smvy.1997.0120","DOIUrl":"10.1006/smvy.1997.0120","url":null,"abstract":"<div><p>The interaction of MS2 coat protein and its translational operator hairpin is a very well-characterized RNA–protein complex. The recent high-resolution cocrystal structure successfully explains many biochemical experiments measuring the affinity of the protein–RNA interaction for mutant proteins and chemically modified RNAs. However, an analysis of a tight binding variant of the RNA suggests that the conformation of the free RNA is also an important determinant of the affinity.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"8 3","pages":"Pages 176-185"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1997.0120","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51140000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Topological Organization of Picornaviral Genomes: Statistical Prediction of RNA Structural Signals","authors":"Ann C. Palmenberg , Jean-Yves Sgro","doi":"10.1006/smvy.1997.0126","DOIUrl":"10.1006/smvy.1997.0126","url":null,"abstract":"<div><p>We have analyzed 11 picornaviral RNA genomic sequences by optimal and suboptimal minimum free energy folding algorithms. The systematic summation of all pairing partners for each base in the suboptimal structures (P-num value) shows a distinct pattern of alternating low and high values when plotted against the sequence length and indicate regions within each genome where secondary structure(s) are likely to play a significant role in virus biology. The individual folds augmented by data from phylogenetic folds, collectively suggest some revisions of existing models for 5′-untranslated regions of cardioviruses and enteroviruses that might better explain the functions of these regions.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"8 3","pages":"Pages 231-241"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1997.0126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51141386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jennifer D. Banks , Karen L. Beemon , Maxine L. Linial
{"title":"RNA Regulatory Elements in the Genomes of Simple Retroviruses","authors":"Jennifer D. Banks , Karen L. Beemon , Maxine L. Linial","doi":"10.1006/smvy.1997.0122","DOIUrl":"10.1006/smvy.1997.0122","url":null,"abstract":"<div><p>The RNA genomes of simple retroviruses encode three genes (<em>gag, pol,</em>and<em>env</em>) which are required for replication. In addition, there are at least three well-defined<em>cis</em>-acting structures which regulate important aspects of the viral life cycle. The packaging signal at the 5′ end of the RNA tags the genomic RNA for specific encapsidation into assembling virus. Since viral Env proteins are translated from spliced mRNAs,<em>cis</em>-acting splicing signals ensure that the proper ratio of spliced and unspliced viral RNAs is present in the infected cell. Finally,<em>cis</em>-acting elements at the 3′ end of the genome promote the export of unspliced RNAs from the nucleus for translation and encapsidation.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"8 3","pages":"Pages 194-204"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1997.0122","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51141065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"RNA recombination in turnip crinkle virus: its role in formation of chimeric RNAs, multimers, and in 3′-end repair","authors":"Anne E. Simon, Peter D. Nagy","doi":"10.1006/smvy.1996.0045","DOIUrl":"https://doi.org/10.1006/smvy.1996.0045","url":null,"abstract":"<div><p>RNA recombination is well documented for an increasing number of viruses and it is thought to have affected viral evolution and adaptation. However, molecular mechanisms mediating crossover events have been studied in only a few viral systems due to difficulties such as the low frequency of the event, and the scattered distribution of junction sites. Therefore, the uniquely high recombination frequency and nonrandom crossover site distribution for recombination among turnip crinkle carmovirus (TCV) RNAs make TCV an excellent model recombination system. Characterization of large numbers of junction sites between two species of TCV satellite RNAs and between the TCV genomic RNA and one of the satellite RNAs revealed for the first time the role of specific sequences and structures in recombination. Also, recombination was found to play a role in formation of novel chimeric RNAs, multimeric forms of satellite RNAs as well in 3′ end repair of mutated satellite RNAs. A replicase-driven template-switching model is presented to explain many common features occurring during recombination in TCV infections.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"7 6","pages":"Pages 373-379"},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1996.0045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137195606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Introduction: Experimental systems of genetic recombination and defective RNA formation in RNA viruses","authors":"Jozef J. Bujarski","doi":"10.1006/smvy.1996.0043","DOIUrl":"https://doi.org/10.1006/smvy.1996.0043","url":null,"abstract":"<div><p>No abstract</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"7 6","pages":"Pages 361-362"},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1996.0043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137195608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Heterologous recombination in the segmented dsRNA genome of bacteriophage Φ6","authors":"Leonard Mindich","doi":"10.1006/smvy.1996.0047","DOIUrl":"https://doi.org/10.1006/smvy.1996.0047","url":null,"abstract":"<div><p>The genome of bacteriophage Φ6 is composed of three segments of dsRNA. It is the only bacteriophage with a dsRNA genome. Plus strand copies of the genomic segments are packaged in a preformed procapsid, where they then serve as templates for minus strand synthesis. The procapsids, composed of four different proteins, contain all the necessary activities to package and replicate the genome. Under conditions where the minus strand synthesis of one of the segments is inhibited, heterologous recombination is facilitated, leading to the formation of chimeric segments. Although the recombination is heterologous, there is generally a sequence identity of about three nucleotides, but ranging from zero to 12 nucleotides, at the cross over sites. Packaging, replication and recombination of the genome can be studied<em>in vitro</em>using purified procapsids and specifically engineered RNA molecules.</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"7 6","pages":"Pages 389-397"},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1996.0047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137195605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Volume contents and index","authors":"","doi":"10.1006/smvy.1996.0051","DOIUrl":"https://doi.org/10.1006/smvy.1996.0051","url":null,"abstract":"<div><p>No abstract</p></div>","PeriodicalId":92955,"journal":{"name":"Seminars in virology","volume":"7 6","pages":"Pages 417-422"},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/smvy.1996.0051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137195609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}