Figure 5

In vivo conjugation of QDs to the N-terminus of mem-EGFP via intein mediated protein splicing. (A) Co-localization of QDot₆₀₅ with mem-EGFP on the cell membrane. Fluorescence images of stage 10 Xenopus embryos microinjected with the probe (QDot₆₀₅-DnaB I_N) shown in red, in one blastomere at the two-cell stage, and then injected with RNA encoding the target protein (DnaB I_C-memEGFP) shown in green, in three of four blastomeres. Yellow shows the overlap between red QDot₆₀₅ and green EGFP indicating successful QD-protein conjugation in a live embryo. (B) In embryos injected with the probe (QDot₆₀₅-DnaB I_N) alone, in the absence of RNA encoding the target protein (DnaB I_C-memEGFP), QDs do not target the cell membrane but remain diffusely localized in the cytosol.