Fig. 1.

Fig. 1.

Visualizing RNA polymerase II and histone modifications in living embryos. (A) Scheme of experiments. Fluorescently labeled Fabs prepared from modification-specific antibodies are injected into 1-cell-stage zebrafish embryos. After the removal of chorions, the embryos are mounted for a light-sheet (SiMView) or a confocal (FV1000) microscope using low-gelling temperature agarose at the 4-cell stage. (B,C) Representative images taken with a SiMView microscope. (B) Fabs specific to RNAP2 Ser2ph (Alexa 488) and H3K9ac (Cy5) were simultaneously injected and imaged using SiMView. RNAP2 Ser2ph Fabs were clearly concentrated in nuclei around the 1k-cell stage, whereas H3K9ac Fabs were enriched in nuclei from the 8-cell stage. Maximum intensity projections of 198 z-sections with 2 μm intervals are shown. Insets show magnified views of the indicated areas. Yellow arrows indicate RNAP2 Ser2ph foci in nuclei. See also Movie 1. Scale bar: 100 μm. (C) Close association of RNAP2 Ser2ph foci with miR-430 transcripts. Embryos were injected with RNAP2 Ser2ph-Fab (Alexa 488) and miR-430 morpholino (Cy3). Maximum intensity projections (30 z-planes with 2 μm intervals) at the 1k-cell stage are shown. See also Movie 2. Scale bar: 10 μm.