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Identification of Stabilizing Mutations in an H5 Hemagglutinin Influenza Virus Protein.
J Virol. 2015 Dec 30; 90(6):2981-92.JV

Abstract

Highly pathogenic avian influenza viruses of the H5N1 subtype continue to circulate in poultry in Asia, Africa, and the Middle East. Recently, outbreaks of novel reassortant H5 viruses have also occurred in North America. Although the number of human infections with highly pathogenic H5N1 influenza viruses continues to rise, these viruses remain unable to efficiently transmit between humans. However, we and others have identified H5 viruses capable of respiratory droplet transmission in ferrets. Two experimentally introduced mutations in the viral hemagglutinin (HA) receptor-binding domain conferred binding to human-type receptors but reduced HA stability. Compensatory mutations in HA (acquired during virus replication in ferrets) were essential to restore HA stability. These stabilizing mutations in HA also affected the pH at which HA undergoes an irreversible switch to its fusogenic form in host endosomes, a crucial step for virus infectivity. To identify additional stabilizing mutations in an H5 HA, we subjected a virus library possessing random mutations in the ectodomain of an H5 HA (altered to bind human-type receptors) to three rounds of treatment at 50°C. We isolated several mutants that maintained their human-type receptor-binding preference but acquired an appreciable increase in heat stability and underwent membrane fusion at a lower pH; collectively, these properties may aid H5 virus respiratory droplet transmission in mammals.

IMPORTANCE

We have identified mutations in HA that increase its heat stability and affect the pH that triggers an irreversible conformational change (a prerequisite for virus infectivity). These mutations were identified in the genetic background of an H5 HA protein that was mutated to bind to human cells. The ability to bind to human-type receptors, together with physical stability and an altered pH threshold for HA conformational change, may facilitate avian influenza virus transmission via respiratory droplets in mammals.

Authors+Show Affiliations

Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.Departments of Cell and Molecular Biology and Chemical Physiology, The Scripps Research Institute, La Jolla, California, USA.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.ERATO Infection-Induced Host Responses Project, Saitama, Japan.College of Life and Health Sciences, Chubu University, Aichi, Japan.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.Departments of Cell and Molecular Biology and Chemical Physiology, The Scripps Research Institute, La Jolla, California, USA Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA ERATO Infection-Induced Host Responses Project, Saitama, Japan Department of Special Pathogens, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo, Japan Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan kawaokay@svm.vetmed.wisc.edu.

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26719265

Citation

Hanson, Anthony, et al. "Identification of Stabilizing Mutations in an H5 Hemagglutinin Influenza Virus Protein." Journal of Virology, vol. 90, no. 6, 2015, pp. 2981-92.
Hanson A, Imai M, Hatta M, et al. Identification of Stabilizing Mutations in an H5 Hemagglutinin Influenza Virus Protein. J Virol. 2015;90(6):2981-92.
Hanson, A., Imai, M., Hatta, M., McBride, R., Imai, H., Taft, A., Zhong, G., Watanabe, T., Suzuki, Y., Neumann, G., Paulson, J. C., & Kawaoka, Y. (2015). Identification of Stabilizing Mutations in an H5 Hemagglutinin Influenza Virus Protein. Journal of Virology, 90(6), 2981-92. https://doi.org/10.1128/JVI.02790-15
Hanson A, et al. Identification of Stabilizing Mutations in an H5 Hemagglutinin Influenza Virus Protein. J Virol. 2015 Dec 30;90(6):2981-92. PubMed PMID: 26719265.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Identification of Stabilizing Mutations in an H5 Hemagglutinin Influenza Virus Protein. AU - Hanson,Anthony, AU - Imai,Masaki, AU - Hatta,Masato, AU - McBride,Ryan, AU - Imai,Hirotaka, AU - Taft,Andrew, AU - Zhong,Gongxun, AU - Watanabe,Tokiko, AU - Suzuki,Yasuo, AU - Neumann,Gabriele, AU - Paulson,James C, AU - Kawaoka,Yoshihiro, Y1 - 2015/12/30/ PY - 2015/10/30/received PY - 2015/12/22/accepted PY - 2016/1/1/entrez PY - 2016/1/1/pubmed PY - 2016/7/23/medline SP - 2981 EP - 92 JF - Journal of virology JO - J. Virol. VL - 90 IS - 6 N2 - UNLABELLED: Highly pathogenic avian influenza viruses of the H5N1 subtype continue to circulate in poultry in Asia, Africa, and the Middle East. Recently, outbreaks of novel reassortant H5 viruses have also occurred in North America. Although the number of human infections with highly pathogenic H5N1 influenza viruses continues to rise, these viruses remain unable to efficiently transmit between humans. However, we and others have identified H5 viruses capable of respiratory droplet transmission in ferrets. Two experimentally introduced mutations in the viral hemagglutinin (HA) receptor-binding domain conferred binding to human-type receptors but reduced HA stability. Compensatory mutations in HA (acquired during virus replication in ferrets) were essential to restore HA stability. These stabilizing mutations in HA also affected the pH at which HA undergoes an irreversible switch to its fusogenic form in host endosomes, a crucial step for virus infectivity. To identify additional stabilizing mutations in an H5 HA, we subjected a virus library possessing random mutations in the ectodomain of an H5 HA (altered to bind human-type receptors) to three rounds of treatment at 50°C. We isolated several mutants that maintained their human-type receptor-binding preference but acquired an appreciable increase in heat stability and underwent membrane fusion at a lower pH; collectively, these properties may aid H5 virus respiratory droplet transmission in mammals. IMPORTANCE: We have identified mutations in HA that increase its heat stability and affect the pH that triggers an irreversible conformational change (a prerequisite for virus infectivity). These mutations were identified in the genetic background of an H5 HA protein that was mutated to bind to human cells. The ability to bind to human-type receptors, together with physical stability and an altered pH threshold for HA conformational change, may facilitate avian influenza virus transmission via respiratory droplets in mammals. SN - 1098-5514 UR - https://www.unboundmedicine.com/medline/citation/26719265/Identification_of_Stabilizing_Mutations_in_an_H5_Hemagglutinin_Influenza_Virus_Protein_ L2 - http://jvi.asm.org/cgi/pmidlookup?view=long&pmid=26719265 DB - PRIME DP - Unbound Medicine ER -