DNA-dependent RNA polymerase (RNAP) catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates (Probable). The highly mobile Rpo4/Rpo7 heterodimer stalk is conditionally required for transcription initiation (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. Belongs to the eukaryotic RPB4 RNA polymerase subunit family.