Influenza viruses (Orthomyxoviruses) encompass a major group of human and animal pathogens and belong to enveloped, segmented, negative stranded RNA viruses. The segment #7 RNA of influenza A viruses encodes two important structural proteins- M1 from unspliced mRNA and M2 from a spliced mRNA. M1 is a relatively small, highly conserved protein (252 aa in type A and 248 aa in type B viruses). M1 is the most abundant protein in virus particles and plays critical roles in many aspects of virus replication. These include (i) dissociation of M1 from the M1/vRNP complex during the entry and uncoating of virus, (ii) nuclear entry of M1, (iii) interaction of M1 with vRNP to form M1/vRNP complex, (iv) role of M1 in the exit of vRNP from nucleus into cytoplasm, (v) interaction of M1 with viral glycoproteins (HA, NA and M2), (vi) membrane binding of M1, (vii) dimer/oligomer formation of M1, (viii) role of M1 in virus budding including (a) recruitment of viral components at the assembly site, (b) recruitment of host components for budding and release of virus particles, (c) virus morphology. Although there are conflicting hypotheses and results on the specific mechanism by which M1 accomplishes many of these functions, M1 must possess specific motifs or domains for carrying out these functions. Our specific objectives in this project are to investigate the role of the following motifs of M1 in virus biology: i. Nuclear localization motif, ii. Membrane binding motifs, iii. RNA/RNP binding motif, iv. Zinc finger motif, v. Glycoprotein (HA, NA, M2) binding motifs, vi. Dimer/oligomerization motif, vii. Others similar to late (L) domain including host protein recruitment motifs. Our preliminary data suggest the presence of an L domain-like motif in influenza virus M1. viii. In addition, we also plan to investigate if M1/vRNP complex or vRNP alone plays any role in selecting the budding site at the apical membrane since we and others have shown that HA, the major glycoprotein, is not the major determinant in apical budding of influenza virus. We plan to use the powerful tools of molecular biology and reverse genetics in identifying these motifs and defining their functions in the virus life cycle. Identification of these motifs and elucidation of their functions in virus biology will be important towards developing small interfering molecules for use in therapy and generating stable attenuated virus mutants for the development of live virus vaccine.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI041681-08
Application #
6865445
Study Section
Special Emphasis Panel (ZRG1-VR (03))
Program Officer
Lacourciere, Karen A
Project Start
1997-09-30
Project End
2008-02-29
Budget Start
2005-03-01
Budget End
2006-02-28
Support Year
8
Fiscal Year
2005
Total Cost
$266,875
Indirect Cost
Name
University of California Los Angeles
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Nayak, Debi P; Balogun, Rilwan A; Yamada, Hiroshi et al. (2009) Influenza virus morphogenesis and budding. Virus Res 143:147-61
Barman, Subrata; Nayak, Debi P (2007) Lipid raft disruption by cholesterol depletion enhances influenza A virus budding from MDCK cells. J Virol 81:12169-78
Hui, Eric Ka-Wai; Barman, Subrata; Tang, Dominic Ho-Ping et al. (2006) YRKL sequence of influenza virus M1 functions as the L domain motif and interacts with VPS28 and Cdc42. J Virol 80:2291-308
Hui, Eric Ka-Wai; Smee, Donald F; Wong, Min-Hui et al. (2006) Mutations in influenza virus M1 CCHH, the putative zinc finger motif, cause attenuation in mice and protect mice against lethal influenza virus infection. J Virol 80:5697-707
Hui, Eric Ka-Wai; Yap, Ee Ming; An, Dong Sung et al. (2004) Inhibition of influenza virus matrix (M1) protein expression and virus replication by U6 promoter-driven and lentivirus-mediated delivery of siRNA. J Gen Virol 85:1877-84
Nayak, Debi P; Hui, Eric Ka-Wai; Barman, Subrata (2004) Assembly and budding of influenza virus. Virus Res 106:147-65
Nayak, Debi P; Hui, Eric K W (2004) The role of lipid microdomains in virus biology. Subcell Biochem 37:443-91
Barman, Subrata; Adhikary, Lopa; Chakrabarti, Alok K et al. (2004) Role of transmembrane domain and cytoplasmic tail amino acid sequences of influenza a virus neuraminidase in raft association and virus budding. J Virol 78:5258-69
Hui, Eric Ka-Wai; Ralston, Katherine; Judd, Amrit K et al. (2003) Conserved cysteine and histidine residues in the putative zinc finger motif of the influenza A virus M1 protein are not critical for influenza virus replication. J Gen Virol 84:3105-13
Barman, Subrata; Adhikary, Lopa; Kawaoka, Yoshihiro et al. (2003) Influenza A virus hemagglutinin containing basolateral localization signal does not alter the apical budding of a recombinant influenza A virus in polarized MDCK cells. Virology 305:138-52

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