Expected and Unexpected Features of the Newly Discovered Bat Influenza A-like Viruses

Ma, Wenjun; García-Sastre, Adolfo; Schwemmle, Martin

Unlike the bat influenza A-like virus surface proteins, some of the internal proteins of HL17NL10 and HL18NL11 seem to be highly compatible with conventional IAVs [8, 9] . This is mainly based on results from viral polymerase reconstitution experiments of a broad variety of IAVs, including the H1N1, H3N2, H5N1, and H7N9 subtypes [8] [9] [10] . In all cases, unimpaired polymerase activity was observed after substitution of the conventional IAV nucleoprotein (NP) with bat influenza A-like NP from either HL17NL10 or HL18NL11. Similarly, the polymerase subunit PB2 of both bat influenza A-like viruses partially supported the polymerase activity of some IAVs [8] [9] [10] . Internal proteins of HL17NL10 and HL18NL11 are fully compatible between each other, including the polymerase subunits [8] . Recently, the crystal structure of the bat influenza A-like virus polymerase complex was solved, providing a more detailed understanding of viral replication and transcription processes of bat influenza A-like viruses and IAVs in general [11] . This might be especially interesting for investigation of the polymerase compatibility between classical IAVs and bat influenza A-like viruses, as some of the polymerase subunits are interchangeable, whereas others are not.