Figure 1.

Comparison of remaining efficiency in living cells upon introduction of various fluorescently labeled miRNA precursors

(A) Phase contrast (PC) images and epi-fluorescent images of the Cy3-and/or Cy5-labeled synthetic let-7a-1 miRNA precursors [single guide strand (top), duplex (middle), pre-miRNA (bottom)] microinjected into the cytoplasm. The guide strands were labeled with Cy3 and the passenger strands with Cy5.

(B) The proportion of remaining strands in the cytoplasm. The results are shown for nine miRNA precursors with guide strands labeled with Cy3 or Alexa 488 and/or passenger strands labeled with Cy5. The proportion of total fluorescence intensity in the cytoplasm at 60 min after microinjection to that at 2 min after microinjection is shown. Guide (green) and passenger (magenta) strands are shown. Error bars represent SD (n = 10–14 cells).

(C) Colocalization of P-body and introduced pre-miRNA. Confocal fluorescence images of P-body visualized with Dcp1a-EGFP (left), let-7a-1 pre-miRNA (Cy5-labeled guide strand, middle), and their merged image (right). The cell-to-cell variation in fluorescence intensity is due to the difference in the amount of miRNA introduced by microinjection.

G and P stand for guide and passenger sequences of miRNA, respectively. Scale bars, 20 μm.