POLR3B

POLR3B is the second largest subunit of RNA polymerase III, the polymerase responsible for synthesizing transfer and small ribosomal RNAs in eukaryotes. The largest subunit and the encoded protein form the catalytic center of RNA polymerase III. Mutations in this gene are a cause of hypomyelinating leukodystrophy.

Full Name

polymerase (RNA) III (DNA directed) polypeptide B

Function

DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Second largest core component of RNA polymerase III which synthesizes small RNAs, such as 5S rRNA and tRNAs. Proposed to contribute to the polymerase catalytic activity and forms the polymerase active center together with the largest subunit. Pol III is composed of mobile elements and RPC2 is part of the core element with the central large cleft and probably a clamp element that moves to open and close the cleft (By similarity).
Plays a key role in sensing and limiting infection by intracellular bacteria and DNA viruses. Acts as nuclear and cytosolic DNA sensor involved in innate immune response. Can sense non-self dsDNA that serves as template for transcription into dsRNA. The 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.

Biological Process

Defense response to virusIEA:UniProtKB-KW
Innate immune responseIEA:UniProtKB-KW
Positive regulation of innate immune responseManual Assertion Based On ExperimentIMP:UniProtKB
Positive regulation of interferon-beta productionManual Assertion Based On ExperimentIMP:UniProtKB
Transcription, DNA-templatedIEA:InterPro

Cellular Location

Nucleus

Involvement in disease

Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism (HLD8):
An autosomal recessive neurodegenerative disorder characterized by early childhood onset of cerebellar ataxia and mild intellectual disabilities associated with diffuse hypomyelination apparent on brain MRI. Variable features include oligodontia and/or hypogonadotropic hypogonadism.