Tissue specific mutagenic and carcinogenic responses in NER defective mouse models

Area of Science:

• Molecular Biology
• Genetics
• Cancer Research

Background:

• The nucleotide excision repair (NER) pathway is crucial for DNA damage removal.
• NER comprises two sub-pathways: transcription-coupled repair (TC-NER) and global-genome repair (GG-NER).
• Defects in NER components can lead to various human genetic disorders and disease phenotypes.

Purpose of the Study:

• To review and discuss phenotypes of available mouse models with defects in NER genes.
• To analyze the relationship between NER sub-pathway defects and tissue-specific tumor development.
• To explore the impact of NER defects on mutagenesis and premature aging.

Main Methods:

• Analysis of existing literature on NER-deficient mouse models.
• Comparison of phenotypes across different NER mouse models, including cancer incidence, mutagenesis, and aging.
• Categorization of models based on GG-NER and TC-NER pathway involvement.

Main Results:

• Mouse models with GG-NER defects (e.g., Xpa, Xpc, Xpe) mimic human xeroderma pigmentosum and are predisposed to spontaneous and UV-induced cancers.
• Mice with TC-NER defects (e.g., Csa, Csb) are generally resistant to tumor development, except in the skin.
• NER factors with extra-pathway functions (e.g., XPB, XPD) can cause severe phenotypes like trichothiodystrophy, often with premature aging but not increased tumor development.

Conclusions:

• NER pathway defects differentially impact cancer susceptibility, with GG-NER defects being strongly linked to tumorigenesis.
• Mouse models provide valuable tools for understanding DNA repair mechanisms and their roles in cancer and aging.
• NER factors with dual roles highlight the complexity of DNA repair and its implications for human health.