POLR3H Human

Polymerase (RNA) III (DNA directed) Polypeptide H, also known as POLR3H or RPC8, is a subunit of the RNA polymerase III complex in humans. This enzyme is crucial for the transcription of DNA into RNA, specifically small non-coding RNAs such as 5S rRNA, snRNAs, tRNAs, and miRNAs .

POLR3H is a DNA-dependent RNA polymerase that catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates . It is a specific peripheral component of the RNA polymerase III complex, which synthesizes small non-coding RNAs from at least 500 distinct genomic loci . POLR3H, along with CRCP/RPC9, forms a mobile stalk that protrudes from the Pol III core and functions primarily in transcription initiation .

RNA polymerase III plays a key role in sensing and limiting infection by intracellular bacteria and DNA viruses. It acts as a nuclear and cytosolic DNA sensor involved in the innate immune response. POLR3H can sense non-self double-stranded DNA (dsDNA) that serves as a template for transcription into double-stranded RNA (dsRNA). These non-self RNA polymerase III transcripts, such as Epstein-Barr virus-encoded RNAs (EBERs), induce type I interferon and NF-kappa-B through the RIG-I pathway .

Mutations in the POLR3H gene have been associated with various diseases, including infantile cerebellar-retinal degeneration and optic atrophy 9 . The gene is involved in pathways related to RNA polymerase III transcription initiation and the innate immune system .

Human recombinant POLR3H is used in various research applications to study its role in transcription and its involvement in the immune response. Understanding the function and regulation of POLR3H can provide insights into the mechanisms of transcription and the body’s defense against pathogens.