Skip to main content
Figure 4 | BMC Evolutionary Biology

Figure 4

From: Independent specialisation of myosin II paralogues in muscle vs. non-muscle functions during early animal evolution: a ctenophore perspective

Figure 4

Expression of PpiMHCIIa, PpiMHCIIb1 and PpiMHCIIb2 in the tentacular apparatus. (A) Schematic drawing of the tentacle root in internal view. The three coloured horizontal lines materialise the three different planes of transverse cryosections corresponding to panels D, I, N (in green), E, J, O (in orange) and F, K, P (in purple). (A’) The tentacle root in external view (corresponding to the side of tentacle insertion). The dotted lines delineate the longitudinal dissections to remove tentacle root lateral expansions in order to obtain the preparations shown in (C, H, M). (A”) Schematic drawing of the tentacle root in longitudinal section, after removal of the lateral expansions following the dotted lines in (A’). Horizontal lines indicating the three planes of cryosections as in (A). (B, G, L) Internal views of isolated tentacle roots showing PpiMHCIIa (B), PpiMHCIIb1 (G), PpiMHCIIb2 (L) expressions. (C, H, M) Longitudinal sections of the tentacle root stained with PpiMHCIIa (C), PpiMHCIIb1 (H), PpiMHCIIb2 (M) anti-sense probes. The aboral pole is at the top in panels (B, C, G, H, L, M). (D-F, I-K, N-P) Transverse cryosections of whole-mount ISH for the three genes, with sectioning plane indicated by the colour of the surrounding line according to the colour code outlined in panel (A). The black arrowhead in (G-J) points to a stained line above the median ridge which appears to be more or less in continuity with the two layered bands labelled M Tcl. (Q) YL1/2 (anti-tyrosylated-α-tubulin, in red) and DAPI (in blue) counterstaining of the region boxed in (N). (R) Higher magnification of the region indicated by the box in (Q). (S) YL1/2 (red) and DAPI (blue) counterstaining of the region boxed in (P). (T-W) Expression of PpiMHCIIb1 gene in tentillae. (T) Whole mount ISH of tentacle and tentillae. (U) Higher magnification view of the region boxed in (T). (V) Transverse cryosection of whole-mount ISH of a tentilla. Two symmetrical muscle fibres are stained. (W) YL1/2 (in red) and DAPI (in blue) counterstaining of (V). The YL1/2 staining in colloblasts is certainly due to non-specific fixation of the antibody on the sticky colloblast granules. (X) Schematic drawing of a tentilla in transverse section. Coll: Colloblasts; F tt: Forming tentillae; LR: Lateral Ridge; MR: Median Ridge; M tcl: Tentacle Muscle progenitors; M tt: Tentilla muscle progenitors; Mu: Muscle fibres; N Tcl: Tentacle Neural cells; N tt: Tentilla Neural cells Tcl: Tentacle; Tt: Tentilla. Scale bars: B, C, G, H, L, M: 100 μm; D-F, I-K, N-P: 200 μm; Q: 100 μm; R, S: 10 μm; T: 50 μm; U, V, W: 25 μm.

Back to article page