Figure 3.

Tracking the intranuclear fate of the Bsr-derived transcripts. (A) Multicolor FISH at the single-cell level. Left, a representative nucleus hybridized with a Cy3-labeled RBII-36 probe (a), an Oregon-green–labeled intronic probe (b), and a Cy5-labeled spliced-probe (c) is shown. (e and f) Superimposition of panels a/b and panels a/c, respectively. Right, intron-containing Bsr precursors can be detected relatively far from the tails of the comet. (B) Characteristic large Bsr RNA signals at the transcription site. Representative “comet-like” (left) and “track-like” (right) RNA signals detected with Cy-3–labeled RBII-36 and spliced probes, respectively. Bars, 5 μm.