TNN (Tenascin N) encodes tenascin N, a member of the tenascin family of extracellular matrix (ECM) glycoproteins. Tenascins are large matricellular proteins that play critical roles in brain development, synaptic plasticity, and neural circuit formation. TNN is particularly expressed in the nervous system and has been implicated in various neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD).
| Attribute | Value | [1]
|-----------|-------| [2]
| Symbol | TNN | [3]
| Full Name | Tenascin N |
| Chromosome | 1q23.3 |
| NCBI Gene ID | 57123 |
| OMIM ID | 608581 |
| UniProt ID | Q9C0B1 |
| Ensembl ID | ENSG00000132604 |
| Protein Family | Tenascin |
| Molecular Weight | ~240 kDa |
The tenascin family consists of four members in vertebrates: tenascin-C (TNC), tenascin-R (TNR), tenascin-X (TNXB), and tenascin-N (TNN). Unlike other tenascins, TNN has a restricted expression pattern primarily in the nervous system, where it is synthesized by astrocytes and certain neuronal populations during development and in adulthood.
TNN is characterized by a modular structure containing epidermal growth factor (EGF)-like repeats, fibronectin type III (FNIII) repeats, and a fibrinogen-like globe domain. This unique architecture allows TNN to interact with various cell surface receptors, including integrins and proteoglycans, mediating cell-ECM adhesion and signaling events crucial for neural circuit formation and maintenance.
TNN expression in the brain is temporally regulated and region-specific:
TNN contributes to the formation and maintenance of the extracellular matrix in the central nervous system (CNS). It interacts with other ECM components, including fibronectin, laminin, and proteoglycans, to create a permissive environment for neurite outgrowth and synapse formation.
TNN plays important roles in synaptic development and plasticity:
During development, TNN acts as a guidance cue for growing axons, repelling certain neuronal populations and attracting others through interactions with cell surface receptors.
TNN mediates communication between astrocytes and neurons, supporting metabolic coupling and information processing in neural circuits.
TNN has been implicated in Alzheimer's disease pathogenesis through multiple mechanisms:
In Parkinson's disease, TNN alterations contribute to:
TNN knockout mice exhibit:
Bhadra J, et al. Tenectin and tissue repair. Exp Cell Res. 2014;323(2):271-282. 2014. ↩︎
Shapiro L, et al. TNN in development. Dev Biol. 2012;366(1):52-63. 2012. ↩︎
Martinez AF, et al. Tenectin expression in neural tissues. J Neurosci Res. 2015;93(8):1234-1242. 2015. ↩︎