Washington State University, School of Molecular Biosciences, 137 Biotechnology Life Sciences, Pullman, WA 99164, USA.
J Bacteriol. 2010 Oct;192(19):4954-62. doi: 10.1128/JB.00667-10. Epub 2010 Jul 30.
DNA damage repair mechanisms have been most thoroughly explored in the eubacterial and eukaryotic branches of life. The methods by which members of the archaeal branch repair DNA are significantly less well understood but have been gaining increasing attention. In particular, the approaches employed by hyperthermophilic archaea have been a general source of interest, since these organisms thrive under conditions that likely lead to constant chromosomal damage. In this work we have characterized the responses of three Sulfolobus solfataricus strains to UV-C irradiation, which often results in double-strand break formation. We examined S. solfataricus strain P2 obtained from two different sources and S. solfataricus strain 98/2, a popular strain for site-directed mutation by homologous recombination. Cellular recovery, as determined by survival curves and the ability to return to growth after irradiation, was found to be strain specific and differed depending on the dose applied. Chromosomal damage was directly visualized using pulsed-field gel electrophoresis and demonstrated repair rate variations among the strains following UV-C irradiation-induced double-strand breaks. Several genes involved in double-strand break repair were found to be significantly upregulated after UV-C irradiation. Transcript abundance levels and temporal expression patterns for double-strand break repair genes were also distinct for each strain, indicating that these Sulfolobus solfataricus strains have differential responses to UV-C-induced DNA double-strand break damage.
DNA 损伤修复机制在真细菌和真核生物分支中得到了最深入的研究。古菌分支中修复 DNA 的方法还远未被充分理解，但越来越受到关注。特别是，嗜热古菌所采用的方法一直是人们普遍关注的焦点，因为这些生物在可能导致染色体持续损伤的条件下茁壮成长。在这项工作中，我们对三种嗜热硫磺酸杆菌（Sulfolobus solfataricus）菌株对 UV-C 照射的反应进行了表征，这种照射通常会导致双链断裂的形成。我们研究了来自两个不同来源的 S. solfataricus 菌株 P2 和 S. solfataricus 菌株 98/2，该菌株是通过同源重组进行定点突变的常用菌株。通过生存曲线和照射后恢复生长的能力来确定细胞的恢复情况，发现这是菌株特异性的，并且取决于施加的剂量而有所不同。使用脉冲场凝胶电泳直接可视化染色体损伤，并在 UV-C 照射诱导的双链断裂后观察到各菌株之间修复率的变化。发现几种与双链断裂修复相关的基因在 UV-C 照射后显著上调。双链断裂修复基因的转录丰度水平和时间表达模式在每个菌株中也不同，这表明这些嗜热硫磺酸杆菌菌株对 UV-C 诱导的 DNA 双链断裂损伤有不同的反应。
