Fig. 1

Map of pKD-hph vector showing the main features and restriction sites used for plasmids construction. P _tcu1 and T _cel6a were used as promoter and terminator, respectively, for the expression of RNAi fragments. A cel5a intron was inserted between P _tcu1 and T _cel6a (a). Two reverse complemented RNAi fragments were inserted into the pKD-hph vector using EcoRV–Kpn1 and Spe1–Not1, respectively. The transcribed hpRNA fragments driven by the P _tcu1 promoter can be processed by Dicer into siRNA, which then directs degradation of the target gene mRNA by RNAi mechanism. The transcription of RNAi fragment can be turned off when copper was present in the media (b)