title: The RecJ2 protein in the thermophilic archaeonThermoplasma acidophilumis a 3'-5' exonuclease that associates with a DNA replication complex.
abstract: RecJ/cell division cycle 45 (Cdc45) proteins are widely conserved in the three domains of life,i.e.in bacteria, Eukarya, and Archaea. Bacterial RecJ is a 5'-3' exonuclease and functions in DNA repair pathways by using its 5'-3' exonuclease activity. Eukaryotic Cdc45 has no identified enzymatic activity but participates in the CMG complex, so named because it is composed of Cdc45, minichromosome maintenance protein complex (MCM) proteins 2-7, and GINS complex proteins (Sld5, Psf11-3). Eukaryotic Cdc45 and bacterial/archaeal RecJ share similar amino acid sequences and are considered functional counterparts. In Archaea, a RecJ homolog inThermococcus kodakarensiswas shown to associate with GINS and accelerate its nuclease activity and was, therefore, designated GAN (GINS-associatednuclease); however, to date, no archaeal RecJ·MCM·GINS complex has been isolated. The thermophilic archaeonThermoplasma acidophilumhas two RecJ-like proteins, designated TaRecJ1 and TaRecJ2. TaRecJ1 exhibited DNA-specific 5'-3' exonuclease activity, whereas TaRecJ2 had 3'-5' exonuclease activity and preferred RNA over DNA. TaRecJ2, but not TaRecJ1, formed a stable complex with TaGINS in a 2:1 molar ratio. Furthermore, the TaRecJ2·TaGINS complex stimulated activity of TaMCM (T. acidophilumMCM) helicasein vitro, and the TaRecJ2·TaMCM·TaGINS complex was also observedin vivoHowever, TaRecJ2 did not interact with TaMCM directly and was not required for the helicase activationin vitroThese findings suggest that the function of archaeal RecJ in DNA replication evolved divergently from Cdc45 despite conservation of the CMG-like complex formation between Archaea and Eukarya.
authors.affiliation: From the Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan and.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ogino
authors.affiliation: From the Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan and.
authors.forename: Sonoko
authors.initials: S
authors.lastname: Ishino
authors.affiliation: the Medical Institute of Bioregulation, Kyushu University, 3-1-1, Maidashi, Higashiku, Fukuoka 812-8582, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kohda
authors.affiliation: From the Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan and ishino@agr.kyushu-u.ac.jp.|the Medical Institute of Bioregulation, Kyushu University, 3-1-1, Maidashi, Higashiku, Fukuoka 812-8582, Japan.
authors.forename: Yoshizumi
authors.initials: Y
authors.lastname: Ishino
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics* / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D003001:Cloning, Molecular; D004265:DNA Helicases / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D019641:DNA, Archaeal / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D005092:Exonucleases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D047468:Immunoprecipitation; D009841:Oligonucleotides / Q000737:chemistry; D011485:Protein Binding; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013822:Thermoplasma / Q000201:enzymology*
chemical_list: D019843:Archaeal Proteins; D018797:Cell Cycle Proteins; D019641:DNA, Archaeal; D004268:DNA-Binding Proteins; D009841:Oligonucleotides; D011994:Recombinant Proteins; D003851:Deoxyribonucleases; D004706:Endodeoxyribonucleases; D005092:Exonucleases; D004265:DNA Helicases
keywords: DNA helicase; DNA repair; DNA replication; archaea; deoxyribonuclease (DNase)