Co-expression of eqFP611 and smGFP4 fusion proteins targeted to mitochondria. Tobacco wild-type protoplasts transfected with plasmids pIVD145-eqFP611 and pIVD145-smGFP4. The eqFP611 and smGFP4 fusion proteins contain the mitochondrial presequence corresponding to the N-terminal 48 amino acids of IVD. Transfected protoplast seen through MitoTracker (A) and FITC (B) filter sets, respectively. Scale bars: 10 μm. (C) Map of plasmids pIVD145-eqFP611 and pIVD145-smGFP4. Black arrow, CaMV 35S: cauliflower mosaic virus 35S promoter; grey box, IVD(145): N-terminal 145 nucleotides of the IVD coding sequence; red box, eqFP611: eqFP611 coding sequence; green box, smGFP4: smGFP4 coding sequence; black box, NOS T: nopaline synthase terminator. H: HindIII, P: PstI, Xb: XbaI, B: BamHI, Sm: SmaI, Sa: SacI, E: EcoRI restriction sites. Vector backbone: pUC19.