POLR3B

POLR3B
Identifiers
Aliases	POLR3B, C128, HLD8, INMAP, RPC2, polymerase (RNA) III subunit B, RNA polymerase III subunit B, CMT1I
External IDs	OMIM: 614366; MGI: 1917678; GeneCards: POLR3B
Enzyme activity
Gene location (Human)
Chr.	Chromosome 12 (human)
End	106,510,198 bp
Gene location (Mouse)
Chr.	Chromosome 10 (mouse)
End	84,563,042 bp
RNA expression pattern
	Top expressed in
	secondary oocyte; ; endothelial cell; ; gingival epithelium; ; amniotic fluid; ; hair follicle; ; kidney tubule; ; germinal epithelium; ; Epithelium of choroid plexus; ; tibialis anterior muscle; ; gonad;
	Top expressed in
	tail of embryo; ; genital tubercle; ; lumbar spinal ganglion; ; epiblast; ; hand; ; submandibular gland; ; granulocyte; ; secondary oocyte; ; primitive streak; ; zygote;
	More reference expression data
	n/a
Gene ontology
Molecular function	transferase activity; DNA binding; nucleotidyltransferase activity; ribonucleoside binding; metal ion binding; RNA polymerase III activity; DNA-directed 5'-3' RNA polymerase activity;
Cellular component	cytosol; nucleoplasm; RNA polymerase III complex; nucleus;
Biological process	immune system process; transcription, DNA-templated; defense response to virus; positive regulation of innate immune response; positive regulation of interferon-beta production; innate immune response; transcription by RNA polymerase III; positive regulation of type I interferon production;
	Sources:Amigo / QuickGO
Orthologs
Databases	NCBI: entry; OMA: entry
	55703
	70428
	ENSG00000013503
	ENSMUSG00000034453
	Q9NW08
	P59470
	NM_018082; NM_001160708
	NM_027423
	NP_001154180; NP_060552
	NP_081699
	Wikidata
View/Edit Human	View/Edit Mouse

RNA polymerase III subunit B is an enzyme that in humans is encoded by the POLR3B gene. It is the second largest subunit of RNA polymerase III. Subunit B is part of the catalytic center of the RNA polymerase III complex.

Gene

The POLR3B gene is located on the long arm (q) of chromosome 12 on position 23.3, from base pair from base pair 106,357,748 to base pair 106,510,198.

Function

RNA polymerase III is an essential enzyme complex responsible for synthesizing small non-coding RNAs, including transfer RNAs (tRNAs) and 5S ribosomal RNA (rRNA) and these small RNAs play a critical role in the process of protein synthesis within cells.

Clinical significance

Mutations in POLR3B are associated with certain genetic disorders, such as 4H leukodystrophy and Charcot–Marie–Tooth disease type 1I.

References

1 2 3 GRCh38: Ensembl release 89: ENSG00000013503 – Ensembl, May 2017
1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000034453 – Ensembl, May 2017
↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
↑ "POLYMERASE III, RNA, SUBUNIT B; POLR3B". omim.org.
↑ Watt KE, Macintosh J, Bernard G, Trainor PA (February 2023). "RNA Polymerases I and III in development and disease". Seminars in Cell & Developmental Biology. 136: 49–63. doi:10.1016/j.semcdb.2022.03.027. PMC 9550887. PMID 35422389.
↑ "POLR3B RNA polymerase III subunit B [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2025-07-31.
1 2 "POLR3B gene: MedlinePlus Genetics". MedlinePlus. U.S. National Library of Medicine.
↑ Lata E, Choquet K, Sagliocco F, Brais B, Bernard G, Teichmann M (2021). "RNA Polymerase III Subunit Mutations in Genetic Diseases". Frontiers in Molecular Biosciences. 8 696438. doi:10.3389/fmolb.2021.696438. PMC 8362101. PMID 34395528.

[refGRCh38Ensembl-1] 1 2 3 GRCh38: Ensembl release 89: ENSG00000013503 – Ensembl, May 2017

[refGRCm38Ensembl-2] 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000034453 – Ensembl, May 2017

[3] "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[4] "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[5] "POLYMERASE III, RNA, SUBUNIT B; POLR3B". omim.org.

[Watt_2023-6] Watt KE, Macintosh J, Bernard G, Trainor PA (February 2023). "RNA Polymerases I and III in development and disease". Seminars in Cell & Developmental Biology. 136: 49–63. doi:10.1016/j.semcdb.2022.03.027. PMC 9550887. PMID 35422389.

[7] "POLR3B RNA polymerase III subunit B [Homo sapiens (human)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2025-07-31.

[MedlinePlus-8] 1 2 "POLR3B gene: MedlinePlus Genetics". MedlinePlus. U.S. National Library of Medicine.

[Lata_2021-9] Lata E, Choquet K, Sagliocco F, Brais B, Bernard G, Teichmann M (2021). "RNA Polymerase III Subunit Mutations in Genetic Diseases". Frontiers in Molecular Biosciences. 8 696438. doi:10.3389/fmolb.2021.696438. PMC 8362101. PMID 34395528.