Comparative analyses of the two proliferating cell nuclear antigens from the hyperthermophilic archaeon, Thermococcus kodakarensis

Authors

  • Yumani Kuba,

    1. Department of Bioscience & Biotechnology, Faculty of Agriculture and Graduate School of Bioresource & Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
    Current affiliation:
    1. Department of Planning and Management, Okinawa Prefectural Institute of Health and Environment, Okinawa, Japan
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  • Sonoko Ishino,

    Corresponding author
    • Department of Bioscience & Biotechnology, Faculty of Agriculture and Graduate School of Bioresource & Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
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  • Takeshi Yamagami,

    1. Department of Bioscience & Biotechnology, Faculty of Agriculture and Graduate School of Bioresource & Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
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  • Masahiro Tokuhara,

    1. Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
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  • Tamotsu Kanai,

    1. Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
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  • Ryosuke Fujikane,

    1. Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan
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  • Hiromi Daiyasu,

    1. Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
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  • Haruyuki Atomi,

    1. Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
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  • Yoshizumi Ishino

    Corresponding author
    • Department of Bioscience & Biotechnology, Faculty of Agriculture and Graduate School of Bioresource & Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
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  • Communicated by: Hiroyuki Araki

Correspondence: ishino@agr.kyushu-u.ac.jp or sonoko@agr.kyushu-u.ac.jp

Abstract

The DNA sliding clamp is a multifunctional protein involved in cellular DNA transactions. In Archaea and Eukaryota, proliferating cell nuclear antigen (PCNA) is the sliding clamp. The ring-shaped PCNA encircles double-stranded DNA within its central hole and tethers other proteins on DNA. The majority of Crenarchaeota, a subdomain of Archaea, have multiple PCNA homologues, and they are capable of forming heterotrimeric rings for their functions. In contrast, most organisms in Euryarchaeota, the other major subdomain, have a single PCNA forming a homotrimeric ring structure. Among the Euryarchaeota whose genome is sequenced, Thermococcus kodakarensis is the only species with two genes encoding PCNA homologues on its genome. We cloned the two genes from the T. kodakarensis genome, and the gene products, PCNA1 and PCNA2, were characterized. PCNA1 stimulated the DNA synthesis reactions of the two DNA polymerases, PolB and PolD, from T. kodakarensis in vitro. PCNA2, however, only had an effect on PolB. We were able to disrupt the gene for PCNA2, whereas gene disruption for PCNA1 was not possible, suggesting that PCNA1 is essential for DNA replication. The sensitivities of the Δpcna2 mutant strain to ultraviolet irradiation (UV), methyl methanesulfonate (MMS) and mitomycin C (MMC) were indistinguishable from those of the wild-type strain.

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