IZUMO1R Gene (Izumo Sperm-Egg Fusion 1 Receptor)
Essential receptor for mammalian fertilization: structure, function, and clinical relevance
Gene Information Card
| Symbol | IZUMO1R |
|---|---|
| Full Name | Izumo Sperm-Egg Fusion 1 Receptor |
| Gene Type | Protein coding |
| Chromosomal Location | 11q21 |
| NCBI Gene ID | 400961 ncbi.nlm.nih.gov/gene/400961 |
| Ensembl ID | ENSG00000196937 |
| UniProt ID | Q1Z1X4 |
| OMIM ID | 615798 |
| HGNC ID | 37292 |
| Aliases | JUNO, FLJ40343, IZUMO1R1 |
Description
IZUMO1R (also known as JUNO) encodes a glycosylphosphatidylinositol (GPI)-anchored cell surface receptor expressed on the oolemma of mature oocytes. It is the cognate receptor for IZUMO1, a sperm-specific protein, and this interaction is essential for sperm-egg fusion during mammalian fertilization. The gene is located on chromosome 11q21 and is conserved across mammals. Loss of IZUMO1R function leads to female infertility due to failure of sperm-egg fusion.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Female infertility due to oocyte defect | Loss-of-function mutations in IZUMO1R prevent binding to sperm IZUMO1, blocking fusion | PMID: 24630722, ClinVar |
| Recurrent implantation failure | Reduced or absent IZUMO1R expression on oocytes may impair fertilization in assisted reproduction | PMID: 28725025 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Ovary | 12.5 | Medium |
| Testis | 0.3 | Not detected |
| Fallopian tube | 8.2 | Low |
| Uterus | 4.1 | Low |
| Placenta | 1.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| K562 | 0.0 | Not detected |
| HeLa | 0.0 | Not detected |
| HEK 293 | 0.0 | Not detected |
| MCF7 | 0.0 | Not detected |
| Oocyte (primary) | High | Cell-type specific expression |
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, no protein expression |
| c.200C>T (p.Thr67Ile) | Missense | Rare | Impaired IZUMO1 binding |
| c.424G>A (p.Gly142Arg) | Missense | Rare | Disrupted GPI anchor attachment |
| c.589C>T (p.Arg197*) | Nonsense | Rare | Truncated protein, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most reported IZUMO1R mutations are loss-of-function, leading to failed sperm-egg fusion and female infertility.
Gain of Function (GOF)
No gain-of-function mutations have been described for IZUMO1R.
Dominant Negative (DN)
No dominant-negative effects have been reported; the phenotype is recessive.
View complete mutation data：
Gene Ontology (GO)
| • binding of sperm to zona pellucida (GO:0007339) | • acrosome reaction (GO:0007340) |
| • penetration of zona pellucida (GO:0007341) | • single fertilization (GO:0007338) |
| • plasma membrane (GO:0005886) | • anchored component of membrane (GO:0031225) |
| • protein binding (GO:0005515) |
Pathways
• Sperm-egg fusion pathway (Reactome: R-HSA-1187000)
• Fertilization (KEGG: hsa04950)
Protein Summary
IZUMO1R (JUNO) is a 250-amino-acid GPI-anchored protein with a single immunoglobulin-like domain. It is specifically expressed on the plasma membrane of mature oocytes and mediates species-specific binding to sperm IZUMO1. The IZUMO1-IZUMO1R interaction is essential for membrane fusion. Structural studies reveal that the binding interface involves key residues in the Ig-like domain. The protein is highly conserved among eutherian mammals.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| IZUMO1R Knockout HEK293 Cell Line | EDJ-KQ13136 | Human | 390243 | Details Get a Quote |
| IZUMO1R Knockout HeLa Cell Line | EDJ-KQ60160 | Human | 390243 | Details Get a Quote |
| IZUMO1R Knockout A-549 Cell Line | EDJ-KQ68621 | Human | 390243 | Details Get a Quote |
| IZUMO1R Knockout HCT 116 Cell Line | EDJ-KQ76990 | Human | 390243 | Details Get a Quote |
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