PMID:23283955

Citation	Desforges, M, Desjardins, J, Zhang, C and Talbot, PJ (2013) The acetyl-esterase activity of the hemagglutinin-esterase protein of human coronavirus OC43 strongly enhances the production of infectious virus. J. Virol. 87:3097-107
Abstract	Most betacoronaviruses possess an hemagglutinin-esterase (HE) protein, which appears to play a role in binding to or release from the target cell. Since this HE protein possesses an acetyl-esterase activity that removes acetyl groups from O-acetylated sialic acid, a role as a receptor-destroying enzyme has been postulated. However, the precise function of HE and of its enzymatic activity remains poorly understood. Making use of neutralizing antibody and of molecular clones of recombinant human coronavirus OC43 (HCoV-OC43), our results suggest that the HE protein of this HCoV could be associated with infection of target cells and, most notably, is important in the production of infectious viral particles. Indeed, after transfecting BHK-21 cells with various cDNA infectious clones of HCoV-OC43, either lacking the HE protein or bearing an HE protein with a nonfunctional acetyl-esterase enzymatic activity, we were reproducibly unable to detect recombinant infectious viruses compared to the reference infectious HCoV-OC43 clone pBAC-OC43(FL). Complementation experiments, using BHK-21 cells expressing wild-type HE, either transiently or in a stable ectopic expression, demonstrate that this protein plays a very significant role in the production of infectious recombinant coronaviral particles that can subsequently more efficiently infect susceptible epithelial and neuronal cells. Even though the S protein is the main viral factor influencing coronavirus infection of susceptible cells, our results taken together indicate that a functionally active HE protein enhances the infectious properties of HCoV-OC43 and contributes to efficient virus dissemination in cell culture.
Links	PubMed PMC3592170 Online version:10.1128/JVI.02699-12
Keywords
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CVHOC:HEMA	involved_in	GO:0019058: viral life cycle	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
CVHOC:HEMA		GO:0019058: viral infectious cycle	ECO:0000315:		P		HE in human coronavirus plays a significant role in the production of an infectious virus, even though the S protein is the main viral factor in coronavirus infection. Figure 4 demonstrates the significant role HE also plays in the production of an infectious viral product. When a functional HE was added to the mutated transfectant, more viral antigens were produced. Figure 4C demonstrates the larger amount of viral antigens present in the transfectants with a functional HE compared to the pcDNA transfectant. Figure 4D demonstrates the significant amount of viral antigens who originally had a mutated HE protein were transfected with a functional HE protein. Therefore, it is apparent that the HE protein plays a significant role in producing infectious viruses.	complete CACAO 7940

References

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