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; HomoloGene: 6981; GeneCards: POLR3B; OMA:POLR3B - orthologs
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
	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.⁵ Subunit B is part of the catalytic center of the RNA polymerase III complex.⁶

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 106,510,198.⁷

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.⁸

Clinical significance

Mutations in POLR3B are associated with certain genetic disorders, such as 4H leukodystrophy and Charcot–Marie–Tooth disease type 1I.⁸⁹

References

GRCh38: Ensembl release 89: ENSG00000013503 – Ensembl, May 2017
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.
"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] GRCh38: Ensembl release 89: ENSG00000013503 – Ensembl, May 2017

[refGRCm38Ensembl-2] 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] "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.

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