Assaying Chimeric Genes in Plants: The GUS Gene Fusion System

DeJi~eitio, r Ge~e lrlt.~irm Much of tile attention and interest in modern molecular biology is fi~cussed on the regulation of gene expression. Factors influencing or mediating such regulation are often best studied using gene Alsions. Gene fusions can be defined its DNA constructions (perfi3rmed ill vitro or i~e Hvo) that result in the coding sequences from one gene (r@o,ter) being transcribed and/or translated under the direction of the controlling sequences of another gene (cmltrr Gene fusions can be of two general types, with many wtriatiuns within types. Transcriptional fusions are defined as fusions in which all protein coding sequences are derived from the reporter, with none from the cmm,//e~. Thus, although the m R N A produced may consist of sequences from both control/o and re/;o~ter, the protein synthesized will be encoded only by the reporter. Translational fusions, in contrast, are defined as those in which the polypeptide produced is the result of coding information provided by both copraoiler and reporter.