This study represents the first functional assignment of the connector domain of a
Mononegavirales
L protein. Furthermore, this study localizes P polymerase cofactor activity to specific amino acids. The functional necessity of this interaction, combined with the uniqueness of L and P proteins to the order
Mononegavirales
, makes disruption of the P-connector site a potential target for developing antivirals against other negative-strand RNA viruses. Furthermore, the connector domain as an acceptor site for the P protein represents a new understanding of
Mononegavirales
L protein biology.
