In addition, previous studies showed that aa mutations in HN protein affect the formation of binding sites to sialic-acid-containing receptors, for instance, the loss of the binding site caused by the Arg516 mutation in NDV HN significantly reduced the fusion properties and growth rate of the virus, demonstrating that the binding site on the NDV HN protein is closely related to virus infection and replication [29]. Here, MT-RNR2 is linked to viral infectious disease.