DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Specific core component of RNA polymerase III which synthesizes small RNAs, such as 5S rRNA and tRNAs (By similarity). Component of the RNA polymerase III (Pol III) complex consisting of 17 subunits. Belongs to the RNA polymerase beta chain family.