FBL (Fibrillarin) Gene
Nucleolar Protein Essential for rRNA Processing and Ribosome Biogenesis
Gene Information Card
| Symbol | FBL |
|---|---|
| Full Name | Fibrillarin |
| Gene Type | Protein coding |
| Chromosomal Location | 19q13.2 |
| NCBI Gene ID | 2091 ncbi.nlm.nih.gov/gene/2091 |
| Ensembl ID | ENSG00000105202 |
| UniProt ID | P22087 |
| OMIM ID | 134795 |
| HGNC ID | 3599 |
| Aliases | FIB, FLJ37505, Nop1, RNU3IP1 |
Description
FBL encodes fibrillarin, a methyltransferase component of box C/D small nucleolar ribonucleoprotein (snoRNP) complexes. Fibrillarin catalyzes 2'-O-methylation of ribosomal RNA (rRNA) and is essential for pre-rRNA processing, ribosome biogenesis, and nucleolar integrity. It is highly conserved across eukaryotes and plays roles in cell proliferation, stress response, and chromatin regulation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Dyskeratosis congenita | FBL mutations impair rRNA methylation and telomere maintenance, leading to bone marrow failure and skin abnormalities. | ClinVar, OMIM |
| Cancer (multiple types) | FBL overexpression drives ribosome biogenesis and cell proliferation; somatic mutations found in breast, lung, and colorectal cancers. | COSMIC, NCBI |
| Ribosomopathies | Defective FBL disrupts ribosome assembly, causing developmental and hematological disorders. | OMIM, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 45.2 | High |
| Bone marrow | 38.1 | High |
| Lymph node | 32.5 | High |
| Brain (cerebellum) | 28.9 | Medium |
| Liver | 15.3 | Medium |
| Heart | 8.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa (cervical) | 52.1 | High expression |
| K562 (leukemia) | 48.7 | High expression |
| A549 (lung) | 35.4 | Medium expression |
| MCF7 (breast) | 30.2 | Medium expression |
| HepG2 (liver) | 22.6 | Medium expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.643G>A (p.Gly215Arg) | Missense | <0.01% | Impaired snoRNP assembly, reduced rRNA methylation |
| c.1021C>T (p.Arg341Trp) | Missense | <0.01% | Loss of methyltransferase activity, nucleolar disorganization |
| c.1240_1242del (p.Lys414del) | Deletion | <0.01% | Dominant-negative effect, defective ribosome biogenesis |
| c.157C>T (p.Arg53Cys) | Missense | <0.01% | Reduced protein stability, associated with dyskeratosis congenita |
Mutation functional classification
Loss of Function (LOF)
Missense mutations (e.g., p.Gly215Arg, p.Arg341Trp) reduce or abolish methyltransferase activity, impairing rRNA processing and ribosome assembly.
Gain of Function (GOF)
Not well documented; overexpression in cancers may confer gain-of-function by enhancing ribosome biogenesis and cell proliferation.
Dominant Negative (DN)
Deletion mutations (e.g., p.Lys414del) produce truncated fibrillarin that disrupts snoRNP complex formation, interfering with wild-type function.
View complete mutation data：
Gene Ontology (GO)
| • nucleolus (GO:0005730) | • rRNA processing (GO:0006364) |
| • rRNA methyltransferase activity (GO:0008649) | • snoRNA binding (GO:0030515) |
| • maturation of LSU-rRNA (GO:0000462) | • maturation of SSU-rRNA (GO:0000466) |
| • RNA binding (GO:0003723) |
Pathways
• Ribosome biogenesis in eukaryotes (KEGG: hsa03008)
• rRNA processing in the nucleolus (Reactome: R-HSA-6791226)
• Major pathway of rRNA processing in the nucleolus (Reactome: R-HSA-6791226)
• Box C/D snoRNP complex assembly (Reactome: R-HSA-6790901)
Protein Summary
Fibrillarin is a 321-amino acid protein (34 kDa) localized to the nucleolus. It contains an N-terminal glycine/arginine-rich (GAR) domain and a methyltransferase domain. As a core component of box C/D snoRNPs, it guides 2'-O-methylation of specific rRNA nucleotides. Fibrillarin also interacts with histones and chromatin modifiers, suggesting roles beyond ribosome biogenesis, including epigenetic regulation and cellular stress responses.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| FBLN1 Knockout HEK293 Cell Line | EDJ-KQ4576 | Human | 2192 | Details Get a Quote |
| FBLN2 Knockout HEK293 Cell Line | EDJ-KQ4578 | Human | 2199 | Details Get a Quote |
| FBLN5 Knockout HEK293 Cell Line | EDJ-KQ7074 | Human | 10516 | Details Get a Quote |
| FBLN7 Knockout HEK293 Cell Line | EDJ-KQ9224 | Human | 129804 | Details Get a Quote |
| FBLL1 Knockout HEK293 Cell Line | EDJ-KQ12689 | Human | 345630 | Details Get a Quote |
| FBLIM1 Knockout HEK293 Cell Line | EDJ-KQ13452 | Human | 54751 | Details Get a Quote |
| FBLN1 Knockout HeLa Cell Line | EDJ-KQ25977 | Human | 2192 | Details Get a Quote |
| FBLIM1 Knockout A-549 Cell Line | EDJ-KQ43014 | Human | 54751 | Details Get a Quote |
| FBLIM1 Knockout HCT 116 Cell Line | EDJ-KQ43015 | Human | 54751 | Details Get a Quote |
| FBLIM1 Knockout HeLa Cell Line | EDJ-KQ43016 | Human | 54751 | Details Get a Quote |
| FBLN1 Knockout A-549 Cell Line | EDJ-KQ27232 | Human | 2192 | Details Get a Quote |
| FBLN1 Knockout HCT 116 Cell Line | EDJ-KQ27233 | Human | 2192 | Details Get a Quote |
| FBLN2 Knockout A-549 Cell Line | EDJ-KQ27238 | Human | 2199 | Details Get a Quote |
| FBLN2 Knockout HeLa Cell Line | EDJ-KQ27239 | Human | 2199 | Details Get a Quote |
| FBLN5 Knockout A-549 Cell Line | EDJ-KQ31901 | Human | 10516 | Details Get a Quote |
Displaying Records 1 To 15 Of 21 Records
