RRP9: U3 Small Nucleolar RNA-Associated Protein 9
Essential Component of the U3 snoRNP Complex in Ribosome Biogenesis
Gene Information Card
| Symbol | RRP9 |
|---|---|
| Full Name | RRP9, U3 Small Nucleolar RNA-Associated Protein 9 |
| Gene Type | Protein coding |
| Chromosomal Location | 3p14.1 |
| NCBI Gene ID | 9136 ncbi.nlm.nih.gov/gene/9136 |
| Ensembl ID | ENSG00000114767 |
| UniProt ID | O43818 |
| OMIM ID | 609912 |
| HGNC ID | 16829 |
| Aliases | U3-55K, U3 small nucleolar RNA-associated protein 9 homolog |
Description
RRP9 encodes a protein component of the U3 small nucleolar ribonucleoprotein (snoRNP) complex, which is essential for early cleavage events in pre-rRNA processing during ribosome biogenesis. The protein localizes to the nucleolus and directly binds U3 snoRNA. RRP9 is conserved across eukaryotes and is critical for 18S rRNA maturation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Diamond-Blackfan anemia (DBA) | Impaired ribosome biogenesis due to RRP9 mutations may disrupt erythropoiesis | ClinVar |
| Cancer (various) | Altered RRP9 expression affects ribosome production and cell proliferation | COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 25.6 | Medium |
| Bone marrow | 18.4 | Medium |
| Lymph node | 15.2 | Medium |
| Brain | 12.1 | Low |
| Liver | 8.5 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 22.3 | Embryonic kidney |
| HeLa | 19.7 | Cervical carcinoma |
| K562 | 17.1 | Leukemia |
| HepG2 | 14.5 | Hepatocellular carcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Loss of start codon, likely loss of function |
| c.287C>T (p.Pro96Leu) | Missense | Rare | Potential disruption of snoRNA binding |
| c.512G>A (p.Arg171Gln) | Missense | Rare | Unknown functional impact |
Mutation functional classification
Loss of Function (LOF)
Mutations that abolish RRP9 protein expression or disrupt U3 snoRNA binding impair pre-rRNA processing and ribosome assembly.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
| • nucleolus (GO:0005730) | • rRNA processing (GO:0006364) |
| • snoRNA binding (GO:0030515) | • small nucleolar ribonucleoprotein complex (GO:0005732) |
| • maturation of SSU-rRNA from tricistronic rRNA transcript (GO:0000462) |
Pathways
• Ribosome biogenesis in eukaryotes (KEGG: hsa03008)
• Major pathway of rRNA processing in the nucleolus (Reactome: R-HSA-6791226)
Protein Summary
RRP9 is a 55 kDa nucleolar protein that binds U3 snoRNA and is a core component of the U3 snoRNP complex. It participates in the early cleavage steps of pre-rRNA processing, specifically at sites A0, A1, and A2, leading to 18S rRNA maturation. The protein contains a coiled-coil domain and a basic region important for RNA binding and nucleolar localization.
Related Services
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