Members of the Mononegavirales including the Paramyxoviridae, like other non-segmented negative strand RNA viruses, have an RNA-dependent RNA polymerase composed of two subunits, a large protein L and a phosphoprotein P. This is a protein family of the L protein. The L protein confers the RNA polymerase activity on the complex. The P protein acts as a transcription factor.
Jiyao W et al.(2023). "The conserved domain database in 2023.",