title: Repair of base damage and genome maintenance in the nucleo-cytoplasmic large DNA viruses.
abstract: Among the DNA viruses, the so-called nucleo-cytoplasmic large DNA viruses (NCLDV) constitute a monophyletic group that currently consists of seven families of viruses infecting a very broad variety of eukaryotes, from unicellular marine protists to humans. Many recent papers have analyzed the sequence and structure of NCLDV genomes and their phylogeny, providing detailed analysis about their genomic structure and evolutionary history and proposing their inclusion in a new viral order named Megavirales that, according to some authors, should be considered as a fourth domain of life, aside from Bacteria, Archaea and Eukarya. The maintenance of genetic information protected from environmental attacks and mutations is essential not only for the survival of cellular organisms but also viruses. In cellular organisms, damaged DNA bases are removed in two major repair pathways: base excision repair (BER) and nucleotide incision repair (NIR) that constitute the major pathways responsible for repairing most endogenous base lesions and abnormal bases in the genome by precise repair procedures. Like cells, many NCLDV encode proteins that might constitute viral DNA repair pathways that would remove damages through BER/NIR pathways. However, the molecular mechanisms and, specially, the biological roles of those viral repair pathways have not been deeply addressed in the literature so far. In this paper, we review viral-encoded BER proteins and the genetic and biochemical data available about them. We propose and discuss probable viral-encoded DNA repair mechanisms and pathways, as compared with the functional and molecular features of known homologs proteins.
authors.affiliation: Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, 28049 Madrid, Spain. Electronic address: modesto.redrejo@csic.es.
authors.forename: Modesto
authors.initials: M
authors.lastname: Redrejo-Rodríguez
authors.affiliation: Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: María L
authors.initials: ML
authors.lastname: Salas
mesh_terms: D004249:DNA Damage; D004260:DNA Repair; D004267:DNA Viruses / Q000201:enzymology / Q000235:genetics*; D016679:Genome, Viral; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D014764:Viral Proteins
keywords: AP endonuclease; Base excision repair; DNA glycosylase; Nucleocytoplasmic large DNA viruses; Polymerase X