TY - JOUR T1 - Coding sequence of firefly luciferase reporter gene affects specific hyper expression in <em>cpl1</em> mutant JF - bioRxiv DO - 10.1101/145011 SP - 145011 AU - Hisashi Koiwa AU - Akihito Fukudome Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/06/02/145011.abstract N2 - Monitoring plant gene expression using promoters of interest fused to reporter-genes became a standard practice in plant molecular biology research. Firefly luciferase (LUC) enables nondestructive monitoring gene expression and widely used for not only quantitative analysis but also screening of mutants altered for gene expression levels. Surprisingly, such screenings frequently identified alleles of CPL1 (Carboxyl-terminal Phosphatase-Like 1) regardless of promoters or pathways studied. In addition, expression of corresponding endogenous genes often show minimal difference between wild type and cpl1. Here we show that coding sequence of LUC reporter gene itself is responsible for high luciferase activity in cpl1 mutant using a classical RD29a-LUC reporter gene as a model system. Deletion of LUC 3'-UTR of insect origin included in classical LUC reporter cassette did not change hyperactivation of LUC in cpl1. However, a reporter gene based on a codon-modified LUC derivative (LUC2) produced similar expression levels both in wild type in cpl1. These results indicate that coding region of classical LUC is responsible for cpl1-specific overexpression of reporter gene, which is uncoupled with endogenous counterpart. ER -