FTSJ1: tRNA 2'-O-Methyltransferase and Intellectual Disability Gene
A comprehensive biomedical overview of FTSJ1, its role in RNA modification, associated diseases, expression, and mutations.
Gene Information Card
| Symbol | FTSJ1 |
|---|---|
| Full Name | FtsJ RNA 2'-O-methyltransferase 1 |
| Gene Type | protein-coding |
| Chromosomal Location | Xp11.23 |
| NCBI Gene ID | 24140 ncbi.nlm.nih.gov/gene/24140 |
| Ensembl ID | ENSG00000168484 |
| UniProt ID | Q9H0U4 |
| OMIM ID | 300499 |
| HGNC ID | 4001 |
| Aliases | FTSJ, MRX9, MRX44, SPB1, TRMT7 |
Description
FTSJ1 encodes a member of the SpoU family of RNA methyltransferases, specifically a tRNA 2'-O-methyltransferase that modifies the 2'-hydroxyl group of ribose in tRNA. This modification is critical for tRNA stability, folding, and translational fidelity. Mutations in FTSJ1 cause X-linked intellectual disability (XLID) by impairing tRNA methylation and protein synthesis, particularly in neurons.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| X-linked intellectual disability 9 (MRX9) | Loss-of-function mutations in FTSJ1 reduce tRNA 2'-O-methylation, leading to defective translation and synaptic dysfunction. | OMIM #300499; ClinVar |
| X-linked intellectual disability 44 (MRX44) | Same mechanism as MRX9; allelic disorder with overlapping phenotypes. | OMIM #300499; ClinVar |
| Non-syndromic X-linked intellectual disability | Missense and nonsense variants disrupt methyltransferase activity, impairing neuronal protein synthesis. | PubMed; ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | Medium |
| Testis | 10.2 | Medium |
| Thyroid | 8.1 | Low |
| Adrenal gland | 7.5 | Low |
| Liver | 5.3 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y (neuroblastoma) | 14.0 | Neuronal model; high expression |
| HEK293 (embryonic kidney) | 9.8 | Moderate expression |
| HeLa (cervical carcinoma) | 7.2 | Low expression |
| K562 (leukemia) | 6.1 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.676C>T (p.Arg226*) | Nonsense | Rare | Loss of function; truncation of methyltransferase domain |
| c.416G>A (p.Arg139His) | Missense | Rare | Reduced catalytic activity; associated with MRX9 |
| c.1A>G (p.Met1?) | Start loss | Rare | Complete loss of protein expression |
| c.802C>T (p.Arg268Trp) | Missense | Rare | Impaired tRNA binding; intellectual disability |
Mutation functional classification
Loss of Function (LOF)
Nonsense, frameshift, and start-loss mutations lead to truncated or absent FTSJ1 protein, reducing tRNA methylation and causing intellectual disability.
Gain of Function (GOF)
No gain-of-function mutations reported for FTSJ1.
Dominant Negative (DN)
No dominant-negative mutations reported; FTSJ1 is X-linked and hemizygous in males.
View complete mutation data：
Gene Ontology (GO)
| • tRNA methylation | • tRNA 2'-O-methylation |
| • RNA methyltransferase activity | • tRNA processing |
| • translation | • cytoplasm |
Pathways
• tRNA modification in the nucleus and cytoplasm
• Protein synthesis and translational fidelity
Protein Summary
FTSJ1 is a 336-amino acid protein localized to the cytoplasm and nucleus. It catalyzes the 2'-O-methylation of tRNA at specific positions (e.g., C32, G34), stabilizing tRNA structure and ensuring accurate codon-anticodon interactions. The protein contains a conserved SpoU methyltransferase domain. Loss of function leads to X-linked intellectual disability due to defective translation in neurons.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| FTSJ1 Knockout HEK293 Cell Line | EDJ-KQ8141 | Human | 24140 | Details Get a Quote |
| FTSJ1 Knockout A-549 Cell Line | EDJ-KQ34032 | Human | 24140 | Details Get a Quote |
| FTSJ1 Knockout HCT 116 Cell Line | EDJ-KQ34033 | Human | 24140 | Details Get a Quote |
| FTSJ1 Knockout HeLa Cell Line | EDJ-KQ34034 | Human | 24140 | Details Get a Quote |
