Single-nucleotide and long-patch base excision repair of DNA damage in plants

• Published in: The Plant journal : for cell and molecular biology Vol. 60; no. 4; pp. 716 - 728
• Main Authors: Córdoba-Cañero, Dolores, Morales-Ruiz, Teresa, Roldán-Arjona, Teresa, Ariza, Rafael R
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.11.2009; Blackwell Publishing Ltd; Blackwell
• Subjects: abasic sites; animals; Arabidopsis; Arabidopsis - enzymology; Arabidopsis - genetics; bacteria; Biochemical analysis; Biochemistry; Biological and medical sciences; biosynthesis; Botany; Cellular biology; Deoxyribonucleic acid; DNA; DNA Damage; DNA Glycosylases; DNA Glycosylases - genetics; DNA Glycosylases - metabolism; DNA polymerase; DNA Repair; DNA, Plant; DNA, Plant - biosynthesis; DNA-(Apurinic or Apyrimidinic Site) Lyase; DNA-(Apurinic or Apyrimidinic Site) Lyase - genetics; DNA-(Apurinic or Apyrimidinic Site) Lyase - metabolism; DNA-directed DNA polymerase; enzymology; evolution; excision; Fundamental and applied biological sciences. Psychology; genetics; glycosylases; Lesions; lyases; metabolism; nucleotides; Original; plant damage; Plant extracts; Plant physiology and development; Proteins; reproduction; uracil; Uracil - metabolism; Yeasts; Site; Vegetals; Excision; DNA polymerase; Enzyme; Arabidopsis; Transferases; abasic sites; DNA repair; Arabidopsis thaliana; Nucleotidyltransferases; Plant; Cruciferae; Dicotyledones; DNA; Angiospermae; Nucleotide; Spermatophyta; Lesion; Repair; Uracil; DNA-directed DNA polymerase
• ISSN: 0960-7412; 1365-313X; 1365-313X
• DOI: 10.1111/j.1365-313x.2009.03994.x

Base excision repair (BER) is a critical pathway in cellular defense against endogenous or exogenous DNA damage. This elaborate multistep process is initiated by DNA glycosylases that excise the damaged base, and continues through the concerted action of additional proteins that finally restore DNA to the unmodified state. BER has been subject to detailed biochemical analysis in bacteria, yeast and animals, mainly through in vitro reproduction of the entire repair reaction in cell-free extracts. However, an understanding of this repair pathway in plants has consistently lagged behind. We report the extension of BER biochemical analysis to plants, using Arabidopsis cell extracts to monitor repair of DNA base damage in vitro. We have used this system to demonstrate that Arabidopsis cell extracts contain the enzymatic machinery required to completely repair ubiquitous DNA lesions, such as uracil and abasic (AP) sites. Our results reveal that AP sites generated after uracil excision are processed both by AP endonucleases and AP lyases, generating either 5'- or 3'-blocked ends, respectively. We have also found that gap filling and ligation may proceed either through insertion of just one nucleotide (short-patch BER) or several nucleotides (long-patch BER). This experimental system should prove useful in the biochemical and genetic dissection of BER in plants, and contribute to provide a broader picture of the evolution and biological relevance of DNA repair pathways.