RNA polymerase 3

Function: - synthesizes small RNAs, including: tRNA, 5SrRNA, 7SK RNA & U6 snRNA - a single stranded DNA template strand of the promoter is positioned within the central active site cleft - a bridging helix emanates from POLR3A & crosses the cleft near the catalytic site & is thought to promote translocation of RNA polymerase 3 by acting as a ratchet that moves the RNA-DNA hybrid through the active site by switching from straight to bent conformations at each step of nucleotide addition (putative) - components of RNA polymerase 3 have a role in sensing & limiting infection by intracellular bacteria & DNA viruses - act as nuclear & 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 3 transcripts, such as Epstein-Barr virus-encoded RNAs (EBERs) induce type 1 interferon & NF- Kappa-B through the RIG-I pathway Structure: - consists of about 17 subunits - RPC3/POLR3C, RPC6/POLR3F & RPC7/POLR3G form a RNA polymerase 3 subcomplex

Properties

COMPARTMENT: cell nucleus MOTIF: active site SUBUNITS: RNA polymerase-3 L' MOTIF: Zinc finger NAME: Zinc finger SITE: 69-82 EFFECTOR-BOUND: Zn+2 MOTIF: Zn+2-binding site SITE: 69-69 Zn+2-binding site SITE: 72-72 Zn+2-binding site SITE: 79-79 Zn+2-binding site SITE: 82-82 Zn+2-binding site SITE: 109-109 Zn+2-binding site SITE: 112-112 Zn+2-binding site SITE: 156-156 Mg+2-binding site SITE: 499-499 Mg+2-binding site SITE: 501-501 Mg+2-binding site SITE: 503-503 Bridging helix {844-856} RNA polymerase 1, 2, 3 17.1 kD subunit (RPABC3, RPB17, RPB8, hRPB8, POLR2H) RNA polymerase I, 2, 2 7.0 kD subunit MOTIF: Zn finger C4-type SITE: 19-39 EFFECTOR-BOUND: Zn+2 RNA polymerase-3 p12.5 MOTIF: Zn finger C4-type SITE: 5-28 EFFECTOR-BOUND: Zn+2 Zinc finger NAME: Zinc finger SITE: 65-107 EFFECTOR-BOUND: Zn+2 RNA polymerase III 32 kD polypeptide MOTIF: glutamate-rich region {147-196} MOTIF: glutamate residue (SEVERAL)

References

UniProt :accession Q9BUI4

Components

DNA-directed RNA polymerase III subunit RPC2; RNA polymerase III subunit C2; C128; DNA-directed RNA polymerase III 127.6 kD polypeptide; DNA-directed RNA polymerase III subunit B (POLR3B) DNA-directed RNA polymerase III subunit RPC3; RNA polymerase III subunit C3; DNA-directed RNA polymerase III subunit C; RNA polymerase III 62 kD subunit; RPC62 (POLR3C) DNA-directed RNA polymerase III subunit RPC4; RNA polymerase III subunit C4; DNA-directed RNA polymerase III subunit D; DNA-directed RNA polymerase III 47 kD polypeptide; RPC53; protein BN51 (POLR3D, BN51, BN51T) DNA-directed RNA polymerase III subunit RPC5; RNA polymerase III subunit C5; DNA-directed RNA polymerase III 80 kD polypeptide (POLR3E, KIAA1452) DNA-directed RNA polymerase III subunit RPC6; RNA polymerase III subunit C6; DNA-directed RNA polymerase III subunit F; RNA polymerase III 39 kD subunit; RPC39 (POLR3F) DNA-directed RNA polymerase III subunit RPC8; RNA polymerase III subunit C8; DNA-directed RNA polymerase III subunit H; RNA polymerase III 22.9 kD subunit; RPC22.9 (POLR3H, KIAA1665, RPC8) RNA polymerase 1, 2, 3 17.1 kD subunit (RPABC3, RPB17, RPB8, hRPB8, POLR2H) RNA polymerase I, 2, 2 7.0 kD subunit RNA polymerase III 32 kD polypeptide (RNA polymerase III C32 subunit) RNA polymerase-3 L' (largest subunit); DNA-directed RNA polymerase 3 subunit RPC1; RNA polymerase 3 subunit C1; DNA-directed RNA polymerase 3 subunit A; DNA-directed RNA polymerase 3 largest subunit (RPC155, C160, POLR3A) RNA polymerase-3 p12.5 (RNA polymerase-3 C11 subunit, HsC11p, hRPC11, protein My010, POLR3K, RPC10)