FIGURE 1.

Schematic representation of the SeV replicative complex. The RNA polymerase is composed of phosphoprotein (P) and large protein L, whereas L (light gray) contains the polymerase activity, and the P tetramer (dark gray) is the cofactor that interacts with L and that is responsible for the interaction with the nucleoprotein N that protects the RNA. These functions reside in the phosphoprotein C-terminus (PCT). More specifically, the phosphoprotein multimerization domain (PMD) contains the interaction site for L, and the structured part of PX contains the interaction site for the N_TAIL domain of N. For L to transcribe or replicate the RNA, P has to progress along the nucleocapsid by transient interactions of its four PX domains with successive N_TAIL domains of the nucleocapsid.