POLR3F, also known as RPC39 and RPC6, belongs to the eukaryotic RPC34/RPC39 RNA polymerase subunit family. POLR3F is one of more than a dozen subunits forming eukaryotic RNA polymerase III (RNA Pol III), which transcribes 5S ribosomal RNA and tRNA genes. This protein has been shown to bind both TFIIIB90 and TBP, two subunits of RNA polymerase III transcription initiation factor IIIB (TFIIIB). It is DNA-dependent RNA polymerase that catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Recombinant human POLR3F protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.