SCX (Scleraxis) Gene
Basic helix-loop-helix transcription factor essential for tendon and ligament development
Gene Information Card
| Symbol | SCX |
|---|---|
| Full Name | Scleraxis bHLH transcription factor |
| Gene Type | protein-coding |
| Chromosomal Location | 8q24.3 |
| NCBI Gene ID | 642658 ncbi.nlm.nih.gov/gene/642658 |
| Ensembl ID | ENSG00000204406 |
| UniProt ID | Q7RTU7 |
| OMIM ID | 609067 |
| HGNC ID | 17719 |
| Aliases | bHLHa48, SCLERAXIS |
Description
SCX encodes a basic helix-loop-helix (bHLH) transcription factor that is a master regulator of tendon and ligament development. It is expressed in tendon progenitor cells and mature tenocytes, where it activates genes involved in collagen synthesis and extracellular matrix organization. SCX is also implicated in cardiac valve development and adult tendon homeostasis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Tendinopathy | Altered SCX expression leads to impaired tendon repair and matrix disorganization | PMID: 25635060 |
| Congenital heart valve defects | SCX knockout mice show abnormal cardiac valve formation | PMID: 17060458 |
| Scleraxis-related myopathy | Rare variants in SCX associated with muscle-tendon junction defects | PMID: 29304370 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Tendon | 45.2 | High |
| Ligament | 38.7 | High |
| Heart | 12.1 | Medium |
| Skeletal muscle | 8.5 | Low |
| Lung | 3.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Tenocytes | 62.3 | Primary tendon cells |
| Cardiac fibroblasts | 18.9 | Valvular interstitial cells |
| C2C12 myoblasts | 2.1 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.331C>T (p.Arg111Trp) | Missense | <0.01% | Reduced DNA binding affinity |
| c.487_489del (p.Lys163del) | In-frame deletion | <0.01% | Altered protein stability |
| c.1A>G (p.Met1Val) | Start loss | <0.01% | Loss of translation initiation |
Mutation functional classification
Loss of Function (LOF)
Missense and deletion variants impair DNA binding or protein stability, reducing transcriptional activation of tendon-specific genes.
Gain of Function (GOF)
No confirmed gain-of-function mutations reported.
Dominant Negative (DN)
Homozygous loss-of-function may act in a dominant-negative manner in heterozygous state due to dimerization interference.
View complete mutation data：
Gene Ontology (GO)
Pathways
• TGF-beta signaling pathway (Reactome: R-HSA-2173789)
• Tendon development (KEGG: hsa04510)
Protein Summary
Scleraxis is a 201-amino acid bHLH transcription factor that forms homodimers or heterodimers with other bHLH proteins (e.g., TCF15). It binds E-box sequences (CANNTG) in the promoters of target genes such as COL1A1, COL1A2, and TNMD, driving tenocyte differentiation and extracellular matrix production. The protein is predominantly nuclear and is essential for embryonic tendon formation and adult tendon repair.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SCX Knockout HEK293 Cell Line | EDJ-KQ15195 | Human | 642658 | Details Get a Quote |
| SCX Knockout HeLa Cell Line | EDJ-KQ47996 | Human | 642658 | Details Get a Quote |
| SCX Knockout A-549 Cell Line | EDJ-KQ69001 | Human | 642658 | Details Get a Quote |
| SCX Knockout HCT 116 Cell Line | EDJ-KQ77359 | Human | 642658 | Details Get a Quote |
