Replication. We assumed that N protein regulates the switch of the role of polymerase between transcription and replication by encapsidating the newly synthesized RNAs [41, 52] . The polymerase that starts the replication at the leader region of the genome requires further supply of N proteins to skip the attenuation signals at each gene junction and thereby to complete each round of replication. Depending on the availability of N proteins, nocap(¼1-encap) fraction of polymerases terminate the replication at each gene junction in our model: dpol r;n;N;1 dt ¼ k e;pol ðencap pol l l l À n sec;N l mRNA;N pol r;n;N;1 Þ ð 15Þ