(a) Diagrammatic representation of eukaryotic Pol II from S. cerevisiae drawn from PDB: 6GYK. CTD refers to the ‘carboxy terminal domain’. (b) The NCLDV-RNAP represented by ASFV-RNAP. This diagrammatic model was drawn from PHYRE2 homology models [114] for ASFV homologs of Pol II subunits, mapped onto the Pol II structure using UCSF Chimera [115]. Homologous RNAP subunits are colour-coded and annotated, please note that the RPB3 and 11 subunits are fused in both ASFV and VACV, and ASFV-RPB7 contains an extended C-terminus, with no homology to characterised proteins [24,28]. Additionally, beyond canonical Pol II subunits, NCLDV-RNAPs also include, based on structurally characterised VACV-RNAP, a stably integrated mRNA capping enzyme (NP868R, highlighted in pale green) and termination factor (Q706L, in pale red) [28,29].