POLM
DNA Polymerase Mu
Gene Information Card
| Symbol | POLM |
|---|---|
| Full Name | DNA Polymerase Mu |
| Gene Type | Protein coding |
| Chromosomal Location | 7p13 |
| NCBI Gene ID | 27434 ncbi.nlm.nih.gov/gene/27434 |
| Ensembl ID | ENSG00000122678 |
| UniProt ID | Q9NP87 |
| OMIM ID | 606344 |
| HGNC ID | 9184 |
| Aliases | Pol mu, DNA polymerase mu, POLM_HUMAN |
Description
POLM encodes DNA polymerase mu, a member of the X family of DNA polymerases. It is involved in non-homologous end joining (NHEJ) and V(D)J recombination, playing a critical role in DNA double-strand break repair and immunoglobulin diversity. POLM exhibits template-dependent and template-independent polymerase activity, with a preference for inserting nucleotides opposite abasic sites and during microhomology-mediated end joining.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Immunodeficiency with hyper-IgM type 2 (HIGM2) | Defective V(D)J recombination due to POLM mutations impairs class switch recombination and somatic hypermutation. | OMIM; PubMed |
| Lung cancer | POLM overexpression or altered activity may contribute to genomic instability and tumor progression. | COSMIC; PubMed |
| Colorectal cancer | Somatic mutations in POLM are associated with microsatellite instability and defective DNA repair. | COSMIC; PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lymph node | 5.2 | Medium |
| Spleen | 4.8 | Medium |
| Bone marrow | 3.9 | Low |
| Testis | 2.1 | Low |
| Brain | 0.8 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 6.1 | Moderate expression |
| HeLa | 4.5 | Moderate expression |
| K562 | 3.2 | Low expression |
| HepG2 | 2.8 | Low expression |
| A549 | 1.5 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1070G>A (p.Arg357His) | Missense | <0.01% | Reduced polymerase activity; associated with immunodeficiency |
| c.1433C>T (p.Pro478Leu) | Missense | <0.01% | Impaired NHEJ repair |
| c.1666_1667insA (p.Thr556Asnfs*2) | Frameshift | <0.01% | Loss of function; truncation |
Mutation functional classification
Loss of Function (LOF)
Missense and frameshift mutations in POLM reduce or abolish DNA polymerase activity, impairing NHEJ and V(D)J recombination.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Not reported.
View complete mutation data：
Gene Ontology (GO)
| • DNA polymerase activity | • DNA binding |
| • DNA repair | • double-strand break repair via nonhomologous end joining |
| • nucleotide binding | • transferase activity |
Pathways
• Non-homologous end joining (NHEJ)
• V(D)J recombination
• DNA double-strand break repair
Protein Summary
DNA polymerase mu is a 494-amino acid protein with a conserved Pol X domain and a BRCT domain. It localizes to the nucleus and interacts with other NHEJ factors such as Ku70/80 and XRCC4. The enzyme can add nucleotides in a template-independent manner, particularly during end joining of DNA breaks with microhomology.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| POLM Knockout HEK293 Cell Line | EDJ-KQ1924 | Human | 27434 | Details Get a Quote |
| POLM Knockout A-549 Cell Line | EDJ-KQ21843 | Human | 27434 | Details Get a Quote |
| POLM Knockout HCT 116 Cell Line | EDJ-KQ21844 | Human | 27434 | Details Get a Quote |
| POLM Knockout HeLa Cell Line | EDJ-KQ21845 | Human | 27434 | Details Get a Quote |
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