DNA-dependent RNA polymerases catalyze the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and a small RNAs, such as 5S rRNA and tRNAs, respectively. Pol II is the central component of the basal RNA polymerase II transcription machinery. Pols are composed of mobile elements that move relative to each other. In Pol II, RBP10 is part of the core element with the central large cleft. Component of the RNA polymerase I (Pol I), RNA polymerase II (Pol II) and RNA polymerase III (Pol III) complexes. Component of the RNA polymerase I (Pol I) complex consisting of 14 subunits: RPA135, RPA190, RPC40, RPA14, RPB5, RPO26, RPA43, RPB8, RPA12, RPB10, RPC19, RPC10, RPA49 and RPA34. The complex is composed of a horseshoe-shaped core containing ten subunits (RPA135, RPA190, RPB5, RPO26, RPB8, RPB10, RPC10, RPA12, RPC19 and RPC40) where RPA135 and RPA190 form the DNA-binding cleft. Outside of the core, RPA14 and RPA43 form the stalk that mediates interactions with transcription initiation factors and newly synthesized RNA. Component of the RNA polymerase II (Pol II) complex consisting of 12 subunits: RPO21, RPB2, RPB3, RPB4, RPB5, RPO26, RPB7, RPB8, RPB9, RPB10 and RPC10. Component of the RNA polymerase III (Pol III) complex consisting of 17 subunits. Present with 5300 molecules/cell in log phase SD medium. Belongs to the archaeal Rpo10/eukaryotic RPB10 RNA polymerase subunit family.