DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit is less well bound than the others (Ref.3). Probably not involved in transcription inititation (Probable). a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate + RNA(n+1) Part of the 13-subunit RNA polymerase complex. Forms a stalk with Rpo7 that extends from the main structure. In purified enzyme appears as 5 forms, each differing by about 200 Da of a covalently bound, negatively charged residue. Not glycosylated. Belongs to the eukaryotic RPB4 RNA polymerase subunit family.