Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
Can J Microbiol. 2014 May;60(5):327-31. doi: 10.1139/cjm-2013-0874.
The repair of DNA damage caused by ultraviolet radiation (UVR) is well understood in both lower and higher organisms. Genetic studies carried out at optimum temperature for growth, 37 °C in Escherichia coli, have revealed the major pathways of DNA repair. We show that E. coli cells grown at 20 °C are more sensitive to UVR than cells grown at 37 °C. The analysis of knockout mutants demonstrates that cells impaired in recombinational DNA repair pathways show increased UV sensitivity at 20 °C. Cells with mutations in the nucleotide excision repair (NER) pathway genes are highly sensitive to UVR when grown at 37 °C and retain that sensitivity when grown at 20 °C, whereas wild-type cells are not sensitive when grown at 37 °C but become more sensitive to UVR when grown at low temperatures. Our results taken along with reports from the literature suggest that the UVR sensitivity of E. coli cells at low temperature could be due to impaired NER function.
在低等和高等生物中，人们对由紫外线辐射（UVR）引起的 DNA 损伤的修复有了很好的理解。在大肠杆菌的最佳生长温度 37°C 下进行的遗传研究揭示了 DNA 修复的主要途径。我们发现，在 20°C 下生长的大肠杆菌细胞比在 37°C 下生长的细胞对 UVR 更敏感。对敲除突变体的分析表明，在重组 DNA 修复途径中受损的细胞在 20°C 下表现出更高的 UV 敏感性。在 37°C 下生长时，核苷酸切除修复（NER）途径基因突变的细胞对 UVR 高度敏感，在 20°C 下生长时仍保持这种敏感性，而野生型细胞在 37°C 下生长时不敏感，但在低温下生长时对 UVR 更敏感。我们的研究结果以及文献中的报道表明，大肠杆菌细胞在低温下的 UVR 敏感性可能是由于 NER 功能受损所致。
