The Mutator transposable element family of maize.

Abstract

It has been nearly 15 years since the first report about the Mutator phenomenon in maize (1). The utility of Mutator plants for efficiently generating tagged mutable alleles is probably the primary reason so many maize geneticists have worked with this transposable element family. On the other hand, the elusive nature of the transposase-encoding element for this family and the complexities of the Mu elements themselves and their regulation have become research topics in their own right. The purpose of this review is to summarize the major findings about Mu elements and to highlight the similarity and differences between Mutator and the “classical” transposable elements of maize, Ac and Spm. The structural features of the diverse Mu elements, the assays employed to measure Mutator activity, the role of methylation in element regulation, the timing of Mutator events during the life of the plant, the impact of stress on Mutator activity, and the molecular analysis of Mu-induced mutants will be discussed. In addition, the unresolved problems and implications of recent findings will be presented.