Alternative definition : KEGG: Nucleotide excision repair (NER) is a mechanism to recognize and repair bulky
DNA damage caused by compounds, environmental carcinogens, and exposure to UV-light.
In humans hereditary defects in the NER pathway are linked to at least three diseases:
xeroderma pigmentosum (XP), Cockayne syndrome (CS), and trichothiodystrophy (TTD).
The repair of damaged DNA involves at least 30 polypeptides within two different sub-pathways
of NER known as transcription-coupled repair (TCR-NER) and global genome repair (GGR-NER).
TCR refers to the expedited repair of lesions located in the actively transcribed
strand of genes by RNA polymerase II (RNAP II). In GGR-NER the first step of damage
recognition involves XPC-hHR23B complex together with XPE complex (in prokaryotes,
uvrAB complex). The following steps of GGR-NER and TCR-NER are similar.;