PORL3K is a small essential subunit of RNA polymerase III, the polymerase responsible for synthesizing transfer and small ribosomal RNAs in eukaryotes. The carboxy-terminal domain of this subunit shares a high degree of sequence similarity to the carboxy-terminal domain of an RNA polymerase II elongation factor. This similarity in sequence is supported by functional studies showing that this subunit is required for proper pausing and termination during transcription. Pseudogenes of this gene are found on chromosomes 13 and 17 Recombinant human PORL3K protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.