POLR2D
RNA Polymerase II Subunit D
Gene Information Card
| Symbol | POLR2D |
|---|---|
| Full Name | RNA Polymerase II Subunit D |
| Gene Type | Protein coding |
| Chromosomal Location | 2q21.1 |
| NCBI Gene ID | 5433 ncbi.nlm.nih.gov/gene/5433 |
| Ensembl ID | ENSG00000115268 |
| UniProt ID | O15514 |
| OMIM ID | 180516 |
| HGNC ID | 9192 |
| Aliases | RPB4, RPB16, RPB5, hsRPB4, POLR2D |
Description
POLR2D encodes the fourth largest subunit of RNA polymerase II, the enzyme responsible for synthesizing messenger RNA in eukaryotes. This subunit is essential for transcription initiation and elongation, and it contributes to the stability of the polymerase complex. Mutations in POLR2D have been linked to neurodevelopmental disorders and cancer.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Neurodevelopmental disorder with hypotonia and variable intellectual disability | Missense mutations impair RNA polymerase II function, reducing transcriptional efficiency | ClinVar, OMIM |
| Colorectal cancer | Somatic mutations (e.g., p.Arg181His) may alter polymerase processivity | COSMIC |
| Breast cancer | Copy number alterations and expression changes observed | COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | Medium |
| Heart | 10.2 | Medium |
| Liver | 8.9 | Low |
| Kidney | 11.3 | Medium |
| Testis | 15.1 | High |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 14.2 | Ubiquitous expression |
| HeLa | 13.8 | High |
| K562 | 12.0 | Medium |
| A549 | 11.5 | Medium |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.542G>A (p.Arg181His) | Missense | <0.1% in general population | Alters subunit interaction; associated with neurodevelopmental disorder |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of protein expression; likely pathogenic |
| c.100C>T (p.Arg34Trp) | Missense | <0.01% | Reduced polymerase activity |
Mutation functional classification
Loss of Function (LOF)
Missense mutations in conserved regions reduce RNA polymerase II assembly and transcription activity.
Gain of Function (GOF)
Not reported for POLR2D.
Dominant Negative (DN)
Some missense variants (e.g., p.Arg181His) may exert dominant-negative effects by disrupting polymerase complex integrity.
View complete mutation data：
Gene Ontology (GO)
| • DNA-directed 5'-3' RNA polymerase activity | • RNA polymerase II complex |
| • nucleus | • transcription initiation |
| • transcription elongation |
Pathways
• RNA polymerase II transcription
• mRNA synthesis
• Gene expression (Transcription)
Protein Summary
POLR2D (RPB4) is a 142-amino acid subunit of RNA polymerase II. It forms a heterodimer with RPB7 and is involved in promoter recognition and transcription start site selection. The protein is highly conserved and essential for cell viability.
Related Services
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