Expression of a reporter gene interrupted by the Candida albicans group I intron is inhibited by base analogs
Expression of a reporter gene interrupted by the Candida albicans group I intron is inhibited by base analogs
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DOI：
10.1093/nar/25.2.431
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发表时间：
1997-01-15
影响因子：
14.9
通讯作者：
Lemay, G
中科院分区：
文献类型：
--
作者：
Mercure, S;Cousineau, L;Lemay, G
我们以前报道的内含子（CaLSU）的25 S核糖体RNA的一些白色念珠菌酵母菌株的鉴定。CaLSU被证明是自我剪接，并有可能采用典型的第一组内含子的二级结构。白色念珠菌菌株中CaLSU的存在与对碱类似物抗真菌剂5-氟胞嘧啶（5-FC）或5-氟尿嘧啶（5-FU）的高度敏感性相关。细胞死亡，从增加基地类似物的增长文化，排除了CaLSU的存在和易感性之间的因果关系的证明基地类似物。在本研究中，将CaLSU插入到非必需lacZ报告基因中，并在酿酒酵母中检测其表达。影响体外自剪接的不同突变对体内报告基因表达也有类似的影响。这表明在体内从报告基因中去除CaLSU是通过I组内含子的典型自剪接机制发生的。碱基类似物在加入培养物后以浓度依赖性方式抑制报告基因产物的表达。这支持了一种模型，其中内含子二级结构的破坏，连续核苷酸类似物的掺入，是决定白色念珠菌细胞对碱基类似物的易感性的主要因素。
We previously reported the identification of an intron (CaLSU) in the 25S ribosomal RNA of some Candida albicans yeast strains. CaLSU was shown to self-splice and has the potential to adopt a secondary structure typical of group I introns. The presence of CaLSU in C.albicans strains correlates with a high degree of susceptibility to base analog antifungal agents, 5-fluorocytosine (5-FC) or 5-fluorouracil (5-FU). Cell death, resulting from addition of base analogs to growing cultures, precluded demonstration of a causal relationship between CaLSU presence and susceptibility to base analogs. In the present study, CaLSU was inserted in a non-essential lacZ reporter gene and expression was examined in Saccharomyces cerevisiae. Different mutations affecting in vitro self-splicing also had similar effects on reporter gene expression in vivo. This indicates that in vivo removal of CaLSU from the reporter gene occurs through the typical self-splicing mechanism of group I introns. Base analogs inhibited expression of the reporter gene product in a concentration-dependent manner upon their addition to the cultures. This supports a model in which disruption of intron secondary structure, consecutive to the incorporation of nucleotide analogs, is a major factor determining the susceptibility of C.albicans cells to base analogs.