Abstract
ABSTRACT The ANP32A is responsible for mammalian-restricted influenza virus polymerase activity. However, the mechanism of ANP32A modulation of polymerase activity remains poorly understood. Here, we report that chicken ANP32A (chANP32A) -X1 and -X2 stimulated mammalian-restricted PB2 627E polymerase activity in a dose-dependent manner. Distinct effects of ANP32A constructs suggested that the 180VK181 residues within chANP32A-X1 are necessary but not sufficient to stimulate PB2 627E polymerase activity. The PB2 N567D, T598V, A613V or F636L mutations promoted PB2 627E polymerase activity and chANP32A-X1 showed additive effects, providing further support that species-specific regulation of ANP32A might be only relevant with the PB2 E627K mutation. Rescue of cycloheximide-mediated inhibition showed that ANP32A is species-specific for modulation of vRNA but not mRNA and cRNA, demonstrating chANP32A-X1 compensated for defective cRNPs produced by PB2 627E virus in mammalian cells. The promoter mutations of cRNA enhanced the restriction of PB2 627E polymerase in mammalian cells, which could be restored by chANP32A-X1, indicating that ANP32A is likely to regulate the interaction of viral polymerase with RNA promoter. Coimmunoprecipitation showed that ANP32A did not affect the primary cRNPs assembly. We propose a model that chANP32A-X1 regulates PB2 627E polymerase for suitable interaction with cRNA promoter for vRNA replication.
Highlights
Facing multiple barriers to cross-species transmission, avian influenza A viruses (AIVs) increase their host range to infect new hosts via a high mutation rate, reassortment of genome segments and antigenic shifts [1]
Sequencing indicated that the nucleotide length was 846 and 834 bp for the two ANP32As, which were the same sizes as the predicted Gallus gallus ANP32A transcript variants X1 (XM_413932) and X2 (XM_004943928) in GenBank, respectively, and named as chANP32A-X1 and chANP32A-X2
ChANP32A, which contains an extra 33aa insertion compared with huANP32A, can restore the mammalian-restricted AIV PB2 627E polymerase activity [24]
Summary
Facing multiple barriers to cross-species transmission, avian influenza A viruses (AIVs) increase their host range to infect new hosts via a high mutation rate, reassortment of genome segments and antigenic shifts [1]. Increasing numbers of AIV subtypes, such as H9N2, H6N1, H10N8, H7N3 and H7N7, have sporadically occurred in humans [6,7,8,9,10,11,12]. This fact has raised serious concerns about the potential of AIV to cause a deadly pandemic similar to the 1918 Spanish influenza [13]. These outbreaks underscore the need to understand how AIV cross species barriers and develop infectivity in humans
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
