How viruses access the nucleus

Cohen, Sarah; Au, Shelly; Panté, Nelly

doi:10.1016/j.bbamcr.2010.12.009

Cited by 127 publications

(106 citation statements)

References 152 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…Many viruses utilize the nuclear pore complex to traffic intact particles, viral proteins, or DNA into the nucleus (37,38). The nuclear pore has been shown to accommodate proteins of sizes up to 39 nm in diameter (32).…”

Section: Resultsmentioning

confidence: 99%

Recombinant Adeno-Associated Virus Utilizes Host Cell Nuclear Import Machinery To Enter the Nucleus

Nicolson

Samulski

2014

J Virol

View full text Add to dashboard Cite

Recombinant adeno-associated viral (rAAV) vectors have garnered much promise in gene therapy applications. However, widespread clinical use has been limited by transduction efficiency. Previous studies suggested that the majority of rAAV accumulates in the perinuclear region of cells, presumably unable to traffic into the nucleus. rAAV nuclear translocation remains illdefined; therefore, we performed microscopy, genetic, and biochemical analyses in vitro in order to understand this mechanism. Lectin blockade of the nuclear pore complex (NPC) resulted in inhibition of nuclear rAAV2. Visualization of fluorescently labeled particles revealed that rAAV2 localized to importin-␤-dense regions of cells in late trafficking steps. Additionally, small interfering RNA (siRNA) knockdown of importin-␤ partially inhibited rAAV2 nuclear translocation and inhibited transduction by 50 to 70%. Furthermore, coimmunopreciptation (co-IP) analysis revealed that capsid proteins from rAAV2 could interact with importin-␤ and that this interaction was sensitive to the small GTPase Ran. More importantly, mutations to key basic regions in the rAAV2 capsid severely inhibited interactions with importin-␤. We tested several other serotypes and found that the extent of importin-␤ interaction varied, suggesting that different serotypes may utilize alternative import proteins for nuclear translocation. Co-IP and siRNA analyses were used to investigate the role of other karyopherins, and the results suggested that rAAV2 may utilize multiple import proteins for nuclear entry. Taken together, our results suggest that rAAV2 interacts with importin-␤ alone or in complex with other karyopherins and enters the nucleus via the NPC. These results may lend insight into the design of novel AAV vectors that have an enhanced nuclear entry capability and transduction potential. IMPORTANCEUse of recombinant adeno-associated viral (rAAV) vectors for gene therapy applications is limited by relatively low transduction efficiency, in part due to cellular barriers that hinder successful subcellular trafficking to the nucleus, where uncoating and subsequent gene expression occur. Nuclear translocation of rAAV has been regarded as a limiting step for successful transduction but it remains ill-defined. We explored potential nuclear entry mechanisms for rAAV2 and found that rAAV2 can utilize the classical nuclear import pathway, involving the nuclear pore complex, the small GTPase Ran, and cellular karyopherins. These results could lend insight into the rational design of novel rAAV vectors that can more efficiently translocate to the nucleus, which may lead to more efficient transduction.

show abstract

Section: Resultsmentioning

confidence: 99%

Recombinant Adeno-Associated Virus Utilizes Host Cell Nuclear Import Machinery To Enter the Nucleus

Nicolson

Samulski

2014

J Virol

View full text Add to dashboard Cite

show abstract

“…To meet the requirements of viral replication, from entry to egress, they orchestrate a complex relationship with cellular factors. Several viruses such as human immunodeficiency virus 1 (HIV-1), influenza A, hepatitis B, and herpes simplex viruses exploit nuclear transport machinery (Cohen et al 2011). Recent studies on retroviruses, particularly HIV-1, have provided insights on these underlying processes.…”

Section: Introductionmentioning

confidence: 99%

Cellular and viral determinants of retroviral nuclear entry

2016

View full text Add to dashboard Cite

Retroviruses must integrate their cDNA into the host genome to generate proviruses. Viral DNA-protein complexes interact with cellular proteins and produce pre-integration complexes, which carry the viral genome and cross the nuclear pore channel to enter the nucleus and integrate viral DNA into host chromosomal DNA. If the reverse transcripts fail to integrate, linear or circular DNA species such as 1-and 2-long terminal repeats are generated. Such complexes encounter numerous cellular proteins in the cytoplasm, which restrict viral infection and protect the nucleus. To overcome host cell defenses, the pathogens have evolved several evasion strategies. Viral proteins often contain nuclear localization signals, allowing entry into the nucleus. Among more than 1000 proteins identified as required for HIV infection by RNA interference screening, karyopherins, cleavage and polyadenylation specific factor 6, and nucleoporins have been predominantly studied. This review discusses current opinions about the synergistic relationship between the viral and cellular factors involved in nuclear import, with focus on the unveiled mysteries of the host-pathogen interaction, and highlights novel approaches to pinpoint therapeutic targets.

show abstract

“…T he nuclear pore is the conduit for transport between the cytoplasm and the nucleus, and as such, it represents an obligatory pathway that must be navigated very early after infection by many classes of human viruses (9,20,21,27,36,44,50,60,62). For herpesviruses, capsid-tegument assemblies must be transported across the cytoplasm, be targeted to and interact with pores, and undergo structural rearrangements promoting genome exit and transport across the pore to the nucleus, where virus immediate early gene transcription ensues (14).…”

mentioning

confidence: 99%

A Nuclear Localization Signal in Herpesvirus Protein VP1-2 Is Essential for Infection via Capsid Routing to the Nuclear Pore

Abaitua

Hollinshead

Bolstad

et al. 2012

J Virol

View full text Add to dashboard Cite

To initiate infection, herpesviruses must navigate to and transport their genomes across the nuclear pore. VP1-2 is a large structural protein of the virion that is conserved in all herpesviruses and plays multiple essential roles in virus replication, including roles in early entry. VP1-2 contains an N-terminal basic motif which functions as an efficient nuclear localization signal (NLS). In this study, we constructed a mutant HSV strain, K.VP1-2ΔNLS, which contains a 7-residue deletion of the core NLS at position 475. This mutant fails to spread in normal cells but can be propagated in complementing cell lines. Electron microscopy (EM) analysis of infection in noncomplementing cells demonstrated capsid assembly, cytoplasmic envelopment, and the formation of extracellular enveloped virions. Furthermore, extracellular virions isolated from noncomplementing cells had similar profiles and abundances of structural proteins. Virions containing VP1-2ΔNLS were able to enter and be transported within cells. However, further progress of infection was prevented, with at least a 500- to 1,000-fold reduction in the efficiency of initiating gene expression compared to that in the revertant. Ultrastructural and immunofluorescence analyses revealed that the K.VP1-2ΔNLS mutant was blocked at the microtubule organizing center or immediately upstream of nuclear pore docking and prior to gene expression. These results indicate that the VP1-2 NLS is not required for the known assembly functions of the protein but is a key requirement for the early routing to the nuclear pore that is necessary for successful infection. Given its conservation, we propose that this motif may also be critical for entry of other classes of herpesviruses.

show abstract

How viruses access the nucleus

Cited by 127 publications

References 152 publications

Recombinant Adeno-Associated Virus Utilizes Host Cell Nuclear Import Machinery To Enter the Nucleus

Recombinant Adeno-Associated Virus Utilizes Host Cell Nuclear Import Machinery To Enter the Nucleus

Cellular and viral determinants of retroviral nuclear entry

A Nuclear Localization Signal in Herpesvirus Protein VP1-2 Is Essential for Infection via Capsid Routing to the Nuclear Pore

Contact Info

Product

Resources

About