The Cytoplasmic Tails of the Influenza Virus Spike Glycoproteins Are Required for Normal Genome Packaging

Zhang, Jie; Leser, George P.; Pekosz, Andrew; Lamb, Robert A.

doi:10.1006/viro.2000.0228

Cited by 83 publications

(68 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Contacts between them, presumably by the connecting densities that are seen in the tomograms (e.g., Fig. 3 a and b) but are at our resolution limit, should involve interactions of the matrix protein with the small endodomain tails of the glycoproteins (29), predicted sizes, 6 (NA; ref. 28) and 10 residues (HA; ref.…”

Section: Influenza Virusmentioning

confidence: 85%

Influenza virus pleiomorphy characterized by cryoelectron tomography

Harris

Cardone

Winkler

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

462

542

View full text Add to dashboard Cite

Influenza virus remains a global health threat, with millions of infections annually and the impending threat that a strain of avian influenza may develop into a human pandemic. Despite its importance as a pathogen, little is known about the virus structure, in part because of its intrinsic structural variability (pleiomorphy): the primary distinction is between spherical and elongated particles, but both vary in size. Pleiomorphy has thwarted structural analysis by image reconstruction of electron micrographs based on averaging many identical particles. In this study, we used cryoelectron tomography to visualize the 3D structures of 110 individual virions of the X-31 (H3N2) strain of influenza A. The tomograms distinguish two kinds of glycoprotein spikes [hemagglutinin (HA) and neuraminidase (NA)] in the viral envelope, resolve the matrix protein layer lining the envelope, and depict internal configurations of ribonucleoprotein (RNP) complexes. They also reveal the stems that link the glycoprotein ectodomains to the membrane and interactions among the glycoproteins, the matrix, and the RNPs that presumably control the budding of nascent virions from host cells. Five classes of virions, four spherical and one elongated, are distinguished by features of their matrix layer and RNP organization. Some virions have substantial gaps in their matrix layer (''molecular fontanels''), and others appear to lack a matrix layer entirely, suggesting the existence of an alternative budding pathway in which matrix protein is minimally involved.envelope glycoproteins ͉ matrix protein ͉ ribonucleoprotein particles ͉ virus assembly ͉ virus structure

show abstract

Section: Influenza Virusmentioning

confidence: 85%

Influenza virus pleiomorphy characterized by cryoelectron tomography

Harris

Cardone

Winkler

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

462

542

View full text Add to dashboard Cite

show abstract

“…Removal of either cytoplasmic tail by itself in a recombinant virus resulted in only mild or moderate defects in virus budding and particle morphology. However, a virus lacking both glycoprotein cytoplasmic tails was found to bud very poorly, and particles were grossly deformed (19,20,29,52). Thus, redundant assembly functions among multiple glycoprotein cytoplasmic tails may be beneficial to a wide variety of enveloped viruses.…”

Section: Discussionmentioning

confidence: 99%

Requirements for Budding of Paramyxovirus Simian Virus 5 Virus-Like Particles

Schmitt

Leser

Waning

et al. 2002

J Virol

Self Cite

133

193

View full text Add to dashboard Cite

Enveloped viruses form at cellular membranes of infected cells by a budding process. Soluble viral components, along with integral membrane glycoprotein spikes, assemble at highly concentrated budding sites, followed by envelopment of the viral core and fission of the membrane to create progeny virions. Much progress has been made in identifying both viral and cellular components that drive this assembly process. For example, alphavirus budding has been found to require both soluble nucleocapsid cores and envelope glycoproteins (9,25,44,45), and a specific interaction between the viral capsid protein and the cytoplasmic tail of the viral E2 glycoprotein is critical for assembly (54). In contrast, the assembly and budding of retroviruses does not require participation of envelope components, and expression of soluble Gag polyprotein in the absence of any other viral component results in efficient budding of virus-like particles (VLPs) that resemble immature virions (46). Several elements within the Gag protein sequence that are important for budding have been identified, including M domains which mediate membrane targeting (1, 31, 32), I domains which direct Gag-Gag interactions (3, 11), and L domains which recruit cellular machinery necessary for membrane fission and virus release (1, 12, 14, 34-36, 41, 43, 48, 49).The parameters that influence the budding of negativestrand RNA viruses are not as well defined. A key role is played by soluble matrix (M) proteins that bind to the inner surfaces of plasma membranes and form an electron-dense layer underlying the virion envelope. Recombinant viruses that lack M proteins have been constructed in the cases of both rabies (27) and measles (4), and in both cases budding was drastically impaired. Furthermore, VLP release has been observed from cells transfected with plasmids encoding M proteins derived from vesicular stomatitis virus (VSV) (16,21,23), Ebola virus (15,47), influenza A virus (13,22), and human parainfluenza virus type 1 (hPIV-1) (5). VLP budding has been examined quantitatively for both VSV (21) and Ebola virus (47), and in both cases budding was remarkably efficient, with Ͼ20% of the M protein released from transfected cells into the culture medium. VLP budding directed by the M proteins of influenza A virus and hPIV-1 has at this point been examined only qualitatively (5,13,22). In all of these cases, budding of particles was observed upon expression of M protein in the absence of any other viral components. However, studies with recombinant viruses, including recombinant rabies virus (26), VSV (40), influenza A virus (20), and the paramyxoviruses Sendai virus (10) and simian virus 5 (SV5) (39) suggest that M proteins may not be sufficient to direct normal budding of a virus, since truncations or sequence alterations to glycoprotein cytoplasmic tails resulted in poor budding, despite the presence of unmodified matrix protein. SV5, like other paramyxoviruses, consists of a core of genomic RNA encapsidated by nucleocapsid (NP) protein that

show abstract

“…Although a direct interaction of the M1 protein with the viral glycoproteins was not demonstrated, expression of HA and NA proteins stimulates membrane association of M1 protein (11). Moreover, a mutant virus with deleted cytoplasmic tails at both HA and NA proteins shows severe defects in particle morphology, genome packaging, and incorporation of NA and M1 into virions (25,55).…”

mentioning

confidence: 99%

The Morphology and Composition of Influenza A Virus Particles Are Not Affected by Low Levels of M1 and M2 Proteins in Infected Cells

Bourmakina

Garcı́a-Sastre

2005

J Virol

View full text Add to dashboard Cite

We generated a recombinant influenza A virus (Mmut) that produced low levels of matrix (M1) and M2 proteins in infected cells. Mmut virus propagated to significantly lower titers than did wild-type virus in cells infected at low multiplicity. By contrast, virion morphology and incorporation of viral proteins and vRNAs into virus particles were similar to those of wild-type virus. We propose that a threshold amount of M1 protein is needed for the assembly of viral components into an infectious particle and that budding is delayed in Mmut virus-infected cells until sufficient levels of M1 protein accumulate at the plasma membrane.Influenza A virus is an enveloped virus of the Orthomyxoviridae family with a segmented negative-strand RNA genome. Its eight viral RNA (vRNA) segments encode the three subunits of the viral RNA polymerase complex, PB1, PB2, and PA; the nucleoprotein NP; the glycoproteins HA and NA; the matrix protein M1; the ion channel protein M2; the nonstructural protein NS1; the nuclear export protein NEP; and the recently discovered facilitator of apoptosis PB1-F2 (7). The M1 protein is a major structural component of the virus particles and forms a layer underneath the lipid cell-derived envelope (43,44). Inside the virions and in infected cells at late stages of the virus replication, the M1 protein associates with the viral ribonucleoproteins (vRNPs), which are composed of viral RNA molecules, multiple copies of the NP, and the three subunits of the viral polymerase holding the ends of the viral RNAs (3, 41, 51). Transcription and replication of the influenza virus genome take place in the nucleus of infected cells. By contrast, assembly of virus particles occurs at the apical surface of the plasma membrane where the M1 protein presumably interacts on one side with the cytoplasmic tails of the glycoproteins anchored in the membrane and on the other side with the vRNPs. Although a direct interaction of the M1 protein with the viral glycoproteins was not demonstrated, expression of HA and NA proteins stimulates membrane association of M1 protein (11). Moreover, a mutant virus with deleted cytoplasmic tails at both HA and NA proteins shows severe defects in particle morphology, genome packaging, and incorporation of NA and M1 into virions (25,55).Previous works show that the M1 protein plays a pivotal role in influenza A virus budding. Mutation of certain residues in the M1 protein dramatically affects the morphology of the virus particles (4, 9

show abstract

The Cytoplasmic Tails of the Influenza Virus Spike Glycoproteins Are Required for Normal Genome Packaging

Cited by 83 publications

References 26 publications

Influenza virus pleiomorphy characterized by cryoelectron tomography

Influenza virus pleiomorphy characterized by cryoelectron tomography

Requirements for Budding of Paramyxovirus Simian Virus 5 Virus-Like Particles

The Morphology and Composition of Influenza A Virus Particles Are Not Affected by Low Levels of M1 and M2 Proteins in Infected Cells

Contact Info

Product

Resources

About