Nucleotide excision repair system

Nucleotide-excision repair systems recognize and remove a variety of bulky lesions and pyrimidine dimers. They excise a segment of the DNA strand including the lesion, leaving a gap that is filled in by DNA polymerase and ligase activities. 

Excision repair. The E. coli mismatch repair is a type of excision repair. However, a different nucleotide excision repair system (NER) is utilized by all organisms from bacteria to human to remove a variety of defects. These include thymine dimers, photohydrates, oxidized bases, adducts of cisplatin (Box 5-B), mutagens derived from polycyclic aromatic compounds,683 and poorly recognized OC mismatched pairs.692 In E. coli this excision repair process depends upon proteins encoded by genes UvrA, B, C, and D and also DNA polymerase I and DNA ligase.693 695a A dimer of protein UvrA forms a complex with helicase UvrB (Eq. 27-22).696 696a... 

Inhibition of DNA repair may result in an adverse event within the cell. As(III) has been shown to inhibit DNA ligase in vitro, but it does not appear to occur by the direct interaction of As(III) with this repair enzyme (Li and Rossman, 1989). It has been suggested that As(III) alters redox levels or affects signal transduction pathways involved with DNA ligase (Hu, Su and Snow, 1998). The nucleotide excision repair system is also impaired by arsenic (Okui and Fujiwara, 1986 Hartwig et al., 1997). 

Reardon JT, Bessho T, Kung HC, Bolton PH, San car A (1997) In vitro repair of oxidative DNA damage by human nucleotide excision repair system possible explanation for neurodegeneration in Xeroderma Pigmentosum patients. Proc Natl Acad Sci USA 94 9463-8... 

Recognition and Removal of Bulky DNA Lesions by the Nucleotide Excision Repair System... 

Bessho, T., Mu, D., and Sancar, A. (1997). Initiation of DNA interstrand cross-link repair in humans The nucleotide excision repair system makes dual incisions 5 to the cross-linked base and removes a 22- to 28-nucleotide long damage free strand. 

Reardon, J. T., Bessho, T., Kung, H. G., Bolton, P. H., and Sancar, A. (1997b). In vitro repair of oxidative DNA dam e by human nucleotide excision repair system Possible explanation for neurodegeneration in xeroderma pigmentosum patients. Proc. Natl. Acad. Sci. USA 94, 9463-9468. 

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