Figure 3. Localization of
pes-10 and
pes-10::lacZ embryonically transcribed RNAs in early embryos. Wild-type embryos (first column) or embryos transformed with a
pes-10::lacZ transgene (second column) were hybridized, respectively, to
pes-10 or lacZ anti-sense probes. Probes were visualized as described in the legend of Fig. 2. Arrows point to nuclei of recently arisen somatic founder blastomeres where the
pes-10::lacZ message has just started to accumulate in two foci. In contrast to the endogenous
pes-10 message, which quickly becomes cytoplasmic (see 7/8-cell stage), the
pes-10::lacZ RNAs remains predominantly nuclear until the 26-cell stage. This apparent block in nuclear export (or cytoplasmic instability) has also been observed for other lacZ fusion RNAs (data not shown), and could be due to the long intron-less coding region of lacZ. Cs refer to the 4 C-derived blastomeres: Caa, Cap, Cpa, Cpp.