RNA and Protein Cell cyclin Expression in the Axon Guidance Mutants and Transgenics. All embryos are shown ventrally. (5a), (5c), (5e), (5f), (5g), (5i), and (5l) are mRNA expression patterns. (5b), (5d), (5h), (5j), and (5k) are protein expression patterns. (5a) CycA RNA expression (blue) in WT embryos, stage 13. The scaffold of the CNS is stained with antibody BP102 (brown). Cells expressing cyclins are visible on the ventral surface in the middle of the segmental commissures of the VNC. (5b) CycA protein staining in WT embryo, showing a similar pattern to the CycA RNA expression. (5c) CycB RNA expression in UR.yf embryos. There is a large increase in cyclin expression and cyclin-expressing cells are away from the midline (black arrow). There are no cyclin expressing cells at the midline. (5d) CycB protein staining in UR.yf embryos (black arrow). The pattern is similar to the RNA expression. (5e). CycB3 RNA expression in FRM embryos. There is an increase of cyclin expression. (5f) and (5g) CycB RNA expression for embryos with robo overexpressed in the muscles (UR.mef); an increase is seen in the muscles (red arrow), with the pleural external oblique muscles clearly visible in (5f). (5h) Cdc2 protein staining in UR.mef embryos. The staining is very clear in the muscles (red arrow) showing cyclin expression on the muscles, whereas in the WT embryos there is no such expression. (5i) CycA RNA expression in a slit embryo. The cyclin expressing cells are present on a narrow region outside of the VNC, compared to their central and lateral location in the WT (compare regions highlighted with the green arrow); staining at the midline cells does not change. (5j) The midline cells express CycB. In a wt embryo, additional cyclin-expressing cells are also visible in the area abutting the midline. However, in the slit embryo, cyclin-expressing cells are not visible in this area, instead appearing pushed outside the VNC. Also the more lateral cells are absent in the slit embryo. (5k) CycB protein staining of a robo12 embryo. As in the slit embryo (5j), cyclin expressing cells are absent from the area abutting the midline. (5l) CycA RNA expression in robo embryos. The cells expressing cyclins are located as in WT.