Species specific differences in use of ANP32 proteins by influenza A virus

Abstract

Influenza A viruses (IAV) are subject to species barriers that prevent frequent zoonotic transmission and pandemics. One of these barriers is the poor activity of avian IAV polymerases in human cells. Differences between avian and mammalian ANP32 proteins underlie this host range barrier. Human ANP32A and ANP32B homologues both support function of human-adapted influenza polymerase but do not support efficient activity of avian IAV polymerase which requires avian ANP32A. We show here that the gene currently designated as avian ANP32B is evolutionarily distinct from mammalian ANP32B, and that chicken ANP32B does not support IAV polymerase activity even of human-adapted viruses. Consequently, IAV relies solely on chicken ANP32A to support its replication in chicken cells. Amino acids 129I and 130N, accounted for the inactivity of chicken ANP32B. Transfer of these residues to chicken ANP32A abolished support of IAV polymerase. Understanding ANP32 function will help develop antiviral strategies and aid the design of influenza virus resilient genome edited chickens.

Influenza A virus interactions with macrophages: Lessons from epithelial cells

“…Furthermore, interactions between host protein ANP32 and the PB2 polymerase subunit were shown to be necessary for optimal viral polymerase activity and IAV vRNA synthesis in a biochemical complementation assay (Sugiyama, Kawaguchi, Okuwaki, & Nagata, 2015). Distinct variants of ANP32 in cells of avian and human origin support only the polymerase activity of avian or human IAV, respectively (Long et al, 2019).…”

Molecular Basis of Host-Adaptation Interactions between Influenza Virus Polymerase PB2 Subunit and ANP32A

“…The former has recently been implicated in host adaptation. 22 The optimal poses determined for the 627- Finally, comparison of PRE profiles of hANP32A:627-NLS(E) demonstrates that this cross-interaction, that represents the case encountered when a non-adapted avian IAV infects human cells, shows less extensive and in general weaker contacts compared to hANP32A:627-NLS(K) and avANP32A:627- figure S8). Absence of 627K diminishes the strong polyvalent contacts present in the former and the shorter IDD and lack of the hexapeptide abrogates the extensive interaction surface and the linker-specific contact present in the latter.…”

“…13 hANP32A lacks an insertion of 33 disordered residues compared to avANP32A, restricting avH5N1 polymerase activity in mammalian cells ( Figure 1A). This restriction is lifted by E627K mutation, suggesting an essential role for ANP32A through interaction with PB2, [14][15][16][17][18][19][20][21][22] although there are currently no molecular descriptions of these interactions. The interaction between ANP32 and influenza polymerase is critical in supporting IAV replication and is attracting increasingly intense interest.…”

“…[16][17][18] Recent studies also point to the importance of related members of the ANP32 family, in particular ANP32B, [19][20][21] as well as the role of surface residues in the folded leucine rich region (LRR) of ANP32A. 22 Conformationally, the 627-NLS region of PB2 exhibits intriguing behaviour. 7,23 X-ray crystallographic structures of both h and av-adapted 627-NLS revealed a compact two-domain structure, 4,7 a conformation also found in full-length transcriptionally-active polymerase.…”

Swine ANP32A supports avian influenza virus polymerase

“…ANP32 proteins possess an N-terminal domain composed of five leucine rich repeats (LRRs) and a C-terminal low complexity acidic region (LCAR) separated by a short region termed the ‘central domain’. In birds and most mammals three ANP32 paralogues are found: ANP32A, ANP32B and ANP32E (11, 12). The roles of ANP32 proteins in cells are diverse and often redundant between the family members but include histone chaperoning, transcriptional regulation, regulation of nuclear export and apoptosis (12).…”