ERCC3 (Excision Repair Cross-Complementation Group 3), also known as TFIIH core component, is a DNA repair gene located on chromosome 19q13.32. The protein encodes a DNA helicase subunit of the transcription factor IIH (TFIIH) complex, which is essential for both transcription initiation and nucleotide excision repair (NER). ERCC3 plays a critical role in transcription-coupled nucleotide excision repair (TC-NER), a pathway that specifically repairs DNA lesions in actively transcribed genes.
The ERCC3 gene spans approximately 15 kb and consists of 17 exons. It encodes a 782-amino acid protein with a molecular weight of approximately 89 kDa. The protein contains seven conserved motifs characteristic of the SF2 helicase family, including the ATP-dependent DNA helicase domain. ERCC3 forms a core component of the TFIIH complex, which contains both repair and transcription activities. [1]
In the nervous system, ERCC3/TFIIH is essential for: [2]
Neurons are particularly dependent on TC-NER due to their high metabolic rate, oxidative stress exposure, and inability to replicate. [3]
Biallelic mutations in ERCC3 cause Cockayne syndrome (CS), a rare autosomal recessive disorder characterized by progressive neurodegeneration, developmental delay, photosensitivity, and premature aging. CS patients exhibit: [4]
CS is considered a segmental progeroid syndrome, sharing features with accelerated aging, including neurodegeneration.
ERCC3 polymorphisms have been associated with Alzheimer's disease (AD) risk in genome-wide association studies (GWAS). The DNA repair capacity declines with age, and impaired TC-NER may contribute to:
Evidence suggests ERCC3 variants may modify Parkinson's disease (PD) risk. DNA repair mechanisms are crucial for maintaining dopaminergic neuron viability, as these cells face high oxidative stress from dopamine metabolism.
ERCC3 and the TFIIH complex represent potential therapeutic targets:
ERCC3 is ubiquitously expressed in all human tissues, including:
ERCC3 interacts with:
ERCC3 is a critical DNA repair and transcription gene whose dysfunction leads to severe neurodegenerative phenotypes. Its role in maintaining genomic integrity in post-mitotic neurons makes it relevant to age-related neurodegenerative diseases including AD and PD.
Weinberg et al. TFIIH and transcription-coupled repair (2019). 2019. ↩︎
Kroker et al. ERCC3 polymorphisms and Alzheimer's disease risk (2014). 2014. ↩︎
Scarolla et al. DNA repair in neurodegenerative diseases (2022). 2022. ↩︎
T Chestovich et al. TFIIH functions in brain development (2007). 2007. ↩︎