TUBB8B Gene - Tubulin Beta 8 Class VIIIb
Genetic, structural, and clinical insights into TUBB8B, a beta-tubulin isotype implicated in oocyte/embryo developmental competence and rare genetic disorders.
Gene Information Card
| Symbol | TUBB8B |
|---|---|
| Full Name | Tubulin beta 8 class VIIIb |
| Gene Type | protein-coding |
| Chromosomal Location | 9q34.3 (GRCh38) |
| NCBI Gene ID | 146781 ncbi.nlm.nih.gov/gene/146781 |
| Ensembl ID | ENSG00000188229 |
| UniProt ID | A6NHL2 |
| OMIM ID | 617043 |
| HGNC ID | 37257 |
| Aliases | TUBB8B, tubulin beta-8B, beta-tubulin 8B |
Description
TUBB8B (tubulin beta 8 class VIIIb) is a protein-coding gene located on chromosome 9q34.3. It encodes a beta-tubulin isotype that is part of the microtubule cytoskeleton. Beta-tubulins are structural components of microtubules, which are essential for cell division, intracellular transport, and maintenance of cell shape. TUBB8B is specifically expressed in oocytes and early embryos, where it plays a critical role in meiotic spindle assembly and embryonic development. Mutations in TUBB8B have been associated with female infertility due to oocyte maturation arrest and embryonic developmental arrest. The gene is also implicated in certain rare genetic disorders affecting neurological development, though the full spectrum of phenotypes is still under investigation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Oocyte maturation arrest | Pathogenic variants in TUBB8B disrupt microtubule dynamics, impairing meiotic spindle formation and leading to oocyte arrest. | ClinVar; OMIM 617043; PMID: 29276000 |
| Embryonic developmental arrest | Mutations affect mitotic spindle function in early cleavage-stage embryos, causing developmental arrest. | ClinVar; PMID: 29276000 |
| Complex cortical dysplasia with other brain malformations (possible) | TUBB8B is expressed in neural tissues; variants may disrupt neuronal migration, though evidence is emerging. | UniProt; literature (PMID: 29276000) |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Ovary | High (nTPM ~ 20-30) | High expression in oocytes |
| Testis | Low (nTPM ~ 5) | Low expression |
| Brain | Moderate (nTPM ~ 10) | Moderate expression in specific regions |
| Other tissues | Low/undetectable | Minimal expression |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Oocytes | High | Key role in meiosis |
| Embryonic stem cells | Moderate | Expressed during early development |
| HeLa (cervical cancer) | Low | Not a primary expression site |
| K562 (leukemia) | Low | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.104G>A (p.Arg35His) | Missense | Rare (found in affected individuals) | Disrupts GTP-binding domain, impairing tubulin polymerization |
| c.802G>A (p.Glu268Lys) | Missense | Rare | Alters microtubule stability, affecting spindle assembly |
| c.124A>G (p.Thr42Ala) | Missense | Rare | May affect protein folding and heterodimer formation |
| c.863C>T (p.Pro288Leu) | Missense | Rare | Impairs microtubule dynamics, leading to meiotic arrest |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations (e.g., frameshift or nonsense) are rare and may lead to haploinsufficiency, but most reported variants are missense with dominant-negative effects.
Gain of Function (GOF)
No clear gain-of-function mutations reported; TUBB8B mutations typically act via dominant-negative mechanisms.
Dominant Negative (DN)
Most pathogenic missense mutations act as dominant-negative, disrupting microtubule polymerization and spindle assembly even in the presence of wild-type allele.
View complete mutation data：
Gene Ontology (GO)
| • GTP binding | • structural constituent of cytoskeleton |
| • microtubule | • microtubule-based process |
| • cell division | • meiotic spindle organization |
Pathways
• Microtubule cytoskeleton organization
• Cell cycle (mitotic and meiotic)
• Oocyte meiosis
Protein Summary
TUBB8B encodes a beta-tubulin protein of approximately 50 kDa (445 amino acids). It forms heterodimers with alpha-tubulin to constitute microtubules. The protein contains a GTP-binding domain essential for polymerization. TUBB8B is highly expressed in oocytes and early embryos, where it is critical for meiotic spindle assembly and chromosomal segregation. Mutations in TUBB8B can cause female infertility due to oocyte maturation arrest or embryonic developmental arrest. The protein also shows moderate expression in brain, suggesting potential roles in neuronal development.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| TUBB8B Knockout HEK293 Cell Line | EDJ-KQ15987 | Human | 260334 | Details Get a Quote |
| TUBB8B Knockout HCT 116 Cell Line | EDJ-KQ47034 | Human | 260334 | Details Get a Quote |
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