Fig. 1. Chimeric luciferase constructs. The maize ubiquitin promoter (black box) plus leader intron (grey line) is fused to the Luc⁺ reporter gene (grey box) in presence of the Nos terminator (black squares). White boxes represent maize introns and their corresponding number is indicated. Restriction sites used to introduce the different introns in the luciferase cDNA are indicated as well as their position in the coding region. Arrowheads indicate primers used for the PCR amplifications.