Soriano S, Creus A, Marcos R, Xamena N
Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Environ Mol Mutagen. 1995;25(2):126-33. doi: 10.1002/em.2850250206.
It has been suggested that transposable elements can be associated with different types of genotoxic effects. For this reason it seems appropriate to outline suitable systems to detect changes in the phenotypic expression of the loci containing transposable elements, as well as those agents that induce such changes. The sex-linked white locus offers a suitable experimental system for studying such events because most of the spontaneous mutations at the white locus are the result of insertions of repeated mobile sequences, and it is easy to follow mutational changes of the locus due to the possibility of detecting even slight changes in eye color. Here we report the results obtained in different strains of Drosophila melanogaster with copia-like induced mutations at the white locus, after treatment with three alkylating agents: ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), and N-nitroso-N-ethylurea (ENU). The three insertional white mutants used in this work were wa4, wbf, and wsp55, with the wa2 mutation used as control because its mutant phenotype is the result of a point mutation instead of the insertion of a DNA fragment. Our data constitute evidence that EMS, MMS, and ENU induce a clear increase in the frequencies of somatic-revertant sectors in the three strains carrying a white allele with an inserted copia-like element. For the wa2 strain, whose mutant phenotype is the result of a point mutation, only ENU at the highest concentration tested is able to induce a significant increase in the somatic reversion frequency. In addition, our results indicate that the use of D. melanogaster strains with transposable elements in the white locus is suitable for detecting genotoxic damage induced by chemicals.
有人提出，转座元件可能与不同类型的基因毒性效应有关。因此，概述合适的系统以检测含有转座元件的基因座的表型表达变化以及诱导此类变化的试剂似乎是合适的。性连锁的白眼基因座提供了一个合适的实验系统来研究此类事件，因为白眼基因座上的大多数自发突变是重复移动序列插入的结果，并且由于能够检测到眼睛颜色的即使是轻微变化，所以很容易追踪该基因座的突变变化。在此，我们报告了在用三种烷化剂处理后，在白眼基因座具有类copia诱导突变的不同黑腹果蝇品系中获得的结果，这三种烷化剂分别是甲磺酸乙酯（EMS）、甲磺酸甲酯（MMS）和N-亚硝基-N-乙基脲（ENU）。本研究中使用的三个插入型白眼突变体是wa4、wbf和wsp55，使用wa2突变体作为对照，因为其突变表型是点突变而非DNA片段插入的结果。我们的数据证明，EMS、MMS和ENU在携带插入了类copia元件的白眼等位基因的三个品系中，诱导体细胞回复扇区频率明显增加。对于wa2品系，其突变表型是点突变的结果，只有在测试的最高浓度下的ENU能够诱导体细胞回复频率显著增加。此外，我们的结果表明，使用白眼基因座带有转座元件的黑腹果蝇品系适用于检测化学物质诱导的基因毒性损伤。
