MYOM2 and infection: Although the M protein of NNSVs is known to play key roles in virus assembly later in infection [1,12], based on the findings from HRSV, VSV and SeV, the M protein also modulates viral RNA synthesis and can inhibit the transcriptase activity through M-NP interaction early in infection, thereby repressing the signal to switch from transcription to packaging into the virion particles [12,55,56].