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Transport of the influenza virus genome from nucleus to nucleus.

Hutchinson EC, Fodor E - Viruses (2013)

Bottom Line: The segmented genome of an influenza virus is encapsidated into ribonucleoprotein complexes (RNPs).Recent studies have shed new light on many of these processes, including the regulation of nuclear export, genome packaging, mechanisms of virion assembly and viral entry and, in particular, the identification of Rab11 on recycling endosomes as a key mediator of RNP transport and genome assembly.This review uses these recent gains in understanding to describe in detail the journey of an influenza A virus RNP from its synthesis in the nucleus through to its entry into the nucleus of a new host cell.

View Article: PubMed Central - PubMed

Affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK. edward.hutchinson@path.ox.ac.uk.

ABSTRACT
The segmented genome of an influenza virus is encapsidated into ribonucleoprotein complexes (RNPs). Unusually among RNA viruses, influenza viruses replicate in the nucleus of an infected cell, and their RNPs must therefore recruit host factors to ensure transport across a number of cellular compartments during the course of an infection. Recent studies have shed new light on many of these processes, including the regulation of nuclear export, genome packaging, mechanisms of virion assembly and viral entry and, in particular, the identification of Rab11 on recycling endosomes as a key mediator of RNP transport and genome assembly. This review uses these recent gains in understanding to describe in detail the journey of an influenza A virus RNP from its synthesis in the nucleus through to its entry into the nucleus of a new host cell.

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Related in: MedlinePlus

The influenza A virus ribonucleoprotein (RNP). The negative-sense RNA of the influenza A virus genome is divided into eight segments, each of which is encapsidated into an RNP. Electron micrographs showing (a) a negatively-stained RNP and (b) longitudinal and (c) transverse views of budding virions; scale bars are 50 nm. In (b) and (c) a complex of eight RNPs is visible as dark rods or dots. (d) Diagram of RNP structure. The NP backbone is based on reference [9] (PDB 4BBL, illustrated using the Python Molecular Viewer [14]); the polymerase and viral RNA, including the terminal promoter structure bound by PB1, are shown schematically. (e, f) Localisation of RNPs in an infected cell. Infected cells were fixed at 7 h (e) or 11 h (f) post-infection, and labelled with antibodies against RNPs (red, ii and iv) and the Rab11 isoform Rab11A (green, iii and v). The selected regions are enlarged 3× in frames iv, v and vi. As the infection progresses RNPs are exported from the nucleus (N) and associate with Rab11 in a perinuclear region for transport across the cytoplasm, then dissociate from Rab11 at the plasma membrane (arrow). Images in (a) reprinted from [15] with permission from Elsevier; in (b, c) adapted by permission from Macmillan Publishers Ltd: Nature [16], copyright (2006) and in (e, f) reproduced from [17] with permission from American Society for Microbiology.
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viruses-05-02424-f001: The influenza A virus ribonucleoprotein (RNP). The negative-sense RNA of the influenza A virus genome is divided into eight segments, each of which is encapsidated into an RNP. Electron micrographs showing (a) a negatively-stained RNP and (b) longitudinal and (c) transverse views of budding virions; scale bars are 50 nm. In (b) and (c) a complex of eight RNPs is visible as dark rods or dots. (d) Diagram of RNP structure. The NP backbone is based on reference [9] (PDB 4BBL, illustrated using the Python Molecular Viewer [14]); the polymerase and viral RNA, including the terminal promoter structure bound by PB1, are shown schematically. (e, f) Localisation of RNPs in an infected cell. Infected cells were fixed at 7 h (e) or 11 h (f) post-infection, and labelled with antibodies against RNPs (red, ii and iv) and the Rab11 isoform Rab11A (green, iii and v). The selected regions are enlarged 3× in frames iv, v and vi. As the infection progresses RNPs are exported from the nucleus (N) and associate with Rab11 in a perinuclear region for transport across the cytoplasm, then dissociate from Rab11 at the plasma membrane (arrow). Images in (a) reprinted from [15] with permission from Elsevier; in (b, c) adapted by permission from Macmillan Publishers Ltd: Nature [16], copyright (2006) and in (e, f) reproduced from [17] with permission from American Society for Microbiology.

Mentions: Influenza infections are caused by members of the orthomyxovirus family. The best-studied genus of the family is the influenza A viruses, the leading cause of influenza in humans and in a wide range of mammals and birds. Influenza B and C viruses also cause influenza in humans and in a more limited range of mammals, and distinct clinical or veterinary diseases are caused by the other genera of the family, the Thogoto, Quaranfil and infectious salmon anaemia viruses [1]. The genomes of orthomyxoviruses are composed of single-stranded, negative-sense RNA, which is divided into multiple segments (eight in the case of influenza A viruses). Each segment is encapsidated by viral proteins into a ribonucleoprotein complex (RNP; Figure 1). Unlike the majority of RNA viruses, for which the replication cycle is confined to the cytoplasm, in the orthomyxovirus family RNPs enter the nucleus of an infected cell to transcribe and replicate. As a result, a newly-synthesised RNP must be transported through a number of cellular compartments, as well as between cells, in order to complete a cycle of infection (Figure 2 and Figure 3). This requires the RNP to interact with multiple cellular transport systems, and a number of recently-published studies have significantly increased our understanding of the mechanisms that transport the RNP through different stages of its journey. In this review, we will follow the course of an influenza A virus RNP from its synthesis in the nucleus of an infected cell through to its entry into another cell’s nucleus, and describe the cellular mechanisms that the RNP recruits for transport along its way.


Transport of the influenza virus genome from nucleus to nucleus.

Hutchinson EC, Fodor E - Viruses (2013)

The influenza A virus ribonucleoprotein (RNP). The negative-sense RNA of the influenza A virus genome is divided into eight segments, each of which is encapsidated into an RNP. Electron micrographs showing (a) a negatively-stained RNP and (b) longitudinal and (c) transverse views of budding virions; scale bars are 50 nm. In (b) and (c) a complex of eight RNPs is visible as dark rods or dots. (d) Diagram of RNP structure. The NP backbone is based on reference [9] (PDB 4BBL, illustrated using the Python Molecular Viewer [14]); the polymerase and viral RNA, including the terminal promoter structure bound by PB1, are shown schematically. (e, f) Localisation of RNPs in an infected cell. Infected cells were fixed at 7 h (e) or 11 h (f) post-infection, and labelled with antibodies against RNPs (red, ii and iv) and the Rab11 isoform Rab11A (green, iii and v). The selected regions are enlarged 3× in frames iv, v and vi. As the infection progresses RNPs are exported from the nucleus (N) and associate with Rab11 in a perinuclear region for transport across the cytoplasm, then dissociate from Rab11 at the plasma membrane (arrow). Images in (a) reprinted from [15] with permission from Elsevier; in (b, c) adapted by permission from Macmillan Publishers Ltd: Nature [16], copyright (2006) and in (e, f) reproduced from [17] with permission from American Society for Microbiology.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814596&req=5

viruses-05-02424-f001: The influenza A virus ribonucleoprotein (RNP). The negative-sense RNA of the influenza A virus genome is divided into eight segments, each of which is encapsidated into an RNP. Electron micrographs showing (a) a negatively-stained RNP and (b) longitudinal and (c) transverse views of budding virions; scale bars are 50 nm. In (b) and (c) a complex of eight RNPs is visible as dark rods or dots. (d) Diagram of RNP structure. The NP backbone is based on reference [9] (PDB 4BBL, illustrated using the Python Molecular Viewer [14]); the polymerase and viral RNA, including the terminal promoter structure bound by PB1, are shown schematically. (e, f) Localisation of RNPs in an infected cell. Infected cells were fixed at 7 h (e) or 11 h (f) post-infection, and labelled with antibodies against RNPs (red, ii and iv) and the Rab11 isoform Rab11A (green, iii and v). The selected regions are enlarged 3× in frames iv, v and vi. As the infection progresses RNPs are exported from the nucleus (N) and associate with Rab11 in a perinuclear region for transport across the cytoplasm, then dissociate from Rab11 at the plasma membrane (arrow). Images in (a) reprinted from [15] with permission from Elsevier; in (b, c) adapted by permission from Macmillan Publishers Ltd: Nature [16], copyright (2006) and in (e, f) reproduced from [17] with permission from American Society for Microbiology.
Mentions: Influenza infections are caused by members of the orthomyxovirus family. The best-studied genus of the family is the influenza A viruses, the leading cause of influenza in humans and in a wide range of mammals and birds. Influenza B and C viruses also cause influenza in humans and in a more limited range of mammals, and distinct clinical or veterinary diseases are caused by the other genera of the family, the Thogoto, Quaranfil and infectious salmon anaemia viruses [1]. The genomes of orthomyxoviruses are composed of single-stranded, negative-sense RNA, which is divided into multiple segments (eight in the case of influenza A viruses). Each segment is encapsidated by viral proteins into a ribonucleoprotein complex (RNP; Figure 1). Unlike the majority of RNA viruses, for which the replication cycle is confined to the cytoplasm, in the orthomyxovirus family RNPs enter the nucleus of an infected cell to transcribe and replicate. As a result, a newly-synthesised RNP must be transported through a number of cellular compartments, as well as between cells, in order to complete a cycle of infection (Figure 2 and Figure 3). This requires the RNP to interact with multiple cellular transport systems, and a number of recently-published studies have significantly increased our understanding of the mechanisms that transport the RNP through different stages of its journey. In this review, we will follow the course of an influenza A virus RNP from its synthesis in the nucleus of an infected cell through to its entry into another cell’s nucleus, and describe the cellular mechanisms that the RNP recruits for transport along its way.

Bottom Line: The segmented genome of an influenza virus is encapsidated into ribonucleoprotein complexes (RNPs).Recent studies have shed new light on many of these processes, including the regulation of nuclear export, genome packaging, mechanisms of virion assembly and viral entry and, in particular, the identification of Rab11 on recycling endosomes as a key mediator of RNP transport and genome assembly.This review uses these recent gains in understanding to describe in detail the journey of an influenza A virus RNP from its synthesis in the nucleus through to its entry into the nucleus of a new host cell.

View Article: PubMed Central - PubMed

Affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK. edward.hutchinson@path.ox.ac.uk.

ABSTRACT
The segmented genome of an influenza virus is encapsidated into ribonucleoprotein complexes (RNPs). Unusually among RNA viruses, influenza viruses replicate in the nucleus of an infected cell, and their RNPs must therefore recruit host factors to ensure transport across a number of cellular compartments during the course of an infection. Recent studies have shed new light on many of these processes, including the regulation of nuclear export, genome packaging, mechanisms of virion assembly and viral entry and, in particular, the identification of Rab11 on recycling endosomes as a key mediator of RNP transport and genome assembly. This review uses these recent gains in understanding to describe in detail the journey of an influenza A virus RNP from its synthesis in the nucleus through to its entry into the nucleus of a new host cell.

Show MeSH
Related in: MedlinePlus