Rabbit Anti-Human POLR3D polyclonal antibody for IHC-P. POLR3D is a DNA dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. It plays a key role in sensing and limiting infection by intracellular bacteria and DNA viruses and acts as nuclear and cytosolic DNA sensor involved in innate immune response.