Comparing the functions of equine and canine influenza H3N8 virus PA-X proteins: Suppression of reporter gene expression and modulation of global host gene expression.
The influenza PA-X protein is translated from the PA open reading frame from frameshifting and suppresses cellular gene expression due to its ribonuclease activity. We further defined the functional roles of PA-X by comparing PA-X proteins from two related viruses - equine influenza (EIV) and canine influenza (CIV) H3N8 - that differ in a C-terminal truncation and internal mutations. In vitro reporter gene assays revealed that both proteins were able to suppress gene expression. Interestingly, EIV PA-X demonstrated ~50% greater activity compared to CIV PA-X, and we identified the mutations that caused this difference. We used RNA-seq to evaluate the effects of PA-X on host gene expression after transfection into cultured cells. There were no significant differences in this property between EIV and CIV PA-X proteins, but expression of either resulted in the up-regulation of genes when compared to controls, most notably immunity-related proteins, trafficking proteins, and transcription factors.
Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Kurtis H
KH
Feng
Computational and Systems Biology 5, Genome Institute of Singapore, Republic of Singapore.
Miao
M
Sun
Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Sho
S
Iketani
Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Biological Sciences and Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
Edward C
EC
Holmes
Department of Microbiology and Immunology, Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. Electronic address: crp3@cornell.edu.
Colin R
CR
Parrish
D000818:Animals; D002460:Cell Line; D016000:Cluster Analysis; D004285:Dogs; D015870:Gene Expression; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006736:Horses; D054884:Host-Pathogen Interactions; D006801:Humans; D053123:Influenza A Virus, H3N8 Subtype / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009976:Orthomyxoviridae Infections / Q000235:genetics* / Q000821:virology*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
C573926:PA-X protein, influenza A virus; D012097:Repressor Proteins; D017361:Viral Nonstructural Proteins
Canine H3N8; Equine H3N8; Gene suppression; Influenza; PA-X; RNA-seq