Functions of yeast helicase Ssl2p that are essential for viability are also involved in protection from the toxicity of adriamycin
Functions of yeast helicase Ssl2p that are essential for viability are also involved in protection from the toxicity of adriamycin
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DOI：
10.1093/nar/gkh582
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发表时间：
2004-04-01
影响因子：
14.9
通讯作者：
Naganuma, A
中科院分区：
文献类型：
--
作者：
Furuchi, T;Takahashi, T;Naganuma, A
我们发现，在酿酒酵母中，DNA 解旋酶 Ssl2p 的过度表达赋予了对阿霉素的抗性。 Ssl2p 作为基本转录因子 TFIIH 的一个亚基，参与转录起始和核苷酸切除修复 (NER)，并且该解旋酶对于酵母细胞的生存至关重要。对 Ssl2p 已知功能与阿霉素耐药性之间关系的检查表明，Ssl2p 的过度表达几乎不会或不会导致 RNA 合成率和 NER 的增加。过量表达缺乏 NER 所必需的羧基末端区域的 Ssl2p 突变体的酵母细胞仍然对阿霉素具有耐药性，这一发现支持了 NER 与阿霉素耐药性无关。当我们检查具有各种缺失的其他突变型 Ssl2p 在酵母中过表达的影响时，我们发现，在 Ssl2p 的 843 个氨基酸中，从位置 81 到位置 750 的整个氨基酸序列对于阿霉素抗性是必需的。该区域与酵母细胞生存所必需的 Ssl2p 区域相同。尽管该区域含有解旋酶基序，但其他酵母解旋酶（例如 Rad3 和 Sgs1）的过度表达对阿霉素耐药性影响很小或没有影响，表明细胞内解旋酶水平的仅仅增加不会导致阿霉素耐药性。我们的结果表明，对于酵母生存至关重要的 Ssl2p 功能对于防止阿霉素毒性也是必需的。
We have found that, in the yeast Saccharomyces cerevisiae, overexpression of the DNA helicase Ssl2p confers resistance to adriamycin. Ssl2p is involved, as a subunit of the basic transcription factor TFIIH, in the initiation of transcription and in nucleotide-excision repair (NER), and this helicase is essential for the survival of yeast cells. An examination of the relationship between the known functions of Ssl2p and adriamycin resistance indicated that overexpression of Ssl2p caused little or no increase in the rate of RNA synthesis and in NER. The absence of any involvement of NER in adriamycin resistance was supported by the finding that yeast cells that overexpressed the mutant form of Ssl2p that lacked the carboxy-terminal region, which is necessary for NER, remained resistant to adriamycin. When we examined the effects of overexpression in yeast of other mutant forms of Ssl2p with various deletions, we found that, of the 843 amino acids of Ssl2p, the entire amino acid sequence from position 81 to position 750 was necessary for adriamycin resistance. This region is identical to the region of Ssl2p that is necessary for the survival of yeast cells. Although this region contains helicase motifs, the overexpression of other yeast helicases, such as Rad3 and Sgs1, had little or no effect on adriamycin resistance, indicating that a mere increase in the intracellular level of helicases does not result in adriamycin resistance. Our results suggest that the functions of Ssl2p that are essential for yeast survival are also required for protection against adriamycin toxicity.