Activation of silent transposable elements.
Activation of silent transposable elements.
复制标题
沉默转座因子的激活。
DOI：
10.1007/978-1-4684-5550-2_24
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Burr,FA
中科院分区：
文献类型：
--
作者：
Burr,B;Burr,FA
玉米遗传学家都知道，引起染色体断裂的因子可以激活静止的转座因子。然而，除了暂时缓解位置效应之外，很难理解这些事件如何直接导致激活。一种可能性是染色体断裂可以启动细胞中的一个过程，导致更高的自发突变率。这样一个系统可以类似于SOS响应ofearthquake ichiacoliin的错误倾向的修复系统诱导。化学诱变剂引起的染色体断裂很小，但增加了庞大的加合物的DNA可以诱导SOS反应。在用甲磺酸乙酯处理过的a1-m2（8004），wx-m8，无活性Spm的纯合子种子中，我们观察到Spm的活化率为1.1 × 10−4。这种材料的自发活化率为1.2 × 10−5。大多数激活事件发生在单个内核中。这一结果与覆盖穗的至少八分之一的区段形成对比，如果活化作为成熟籽粒中诱变的直接结果而发生，则预期该区段会覆盖穗的至少八分之一。这些事件发生的时间较晚表明，在大多数情况下，激活可能不是化学诱变的直接结果。
It is well known among maize geneticists that agents that cause chromosome breakage can activate quiescent transposable elements. However, other than temporarily relieving position effect, it is difficult to understand how these events can lead directly to activation. One possibility is that chromosome breakage can initiate a process in the cell resulting in a higher rate of spontaneous mutation. Such a system could be analogous to the SOS response ofEscherichiacoliin which an error-prone repair system is induced. Chemical mutagens that cause little chromosome breakage but add bulky adducts to the DNA can induce the SOS response. In seed homozygous fora1-m2(8004),wx-m8, no activeSpm, that had been treated with ethyl methanesulfonate, we observed activation ofSpmat the rate of 1.1 × 10−4. The spontaneous rate of activation in this material was 1.2 × 10−5. Most of the activation events occurred as single kernels. This result contrasts with sectors covering at least one-eighth of the ear that would have been expected if activation had occurred as a direct result of mutagenesis in the mature kernel. The late timing of these events suggests that the activation, in most instances, may not be the direct result of chemical mutagenesis.