Journal: EvoDevo
Article Title: The evolution of cephalic fins in manta rays and their relatives: functional evidence for initiation of domain splitting and modulation of the Wnt signaling pathway in the pectoral fin AER of the little skate
doi: 10.1186/s13227-024-00233-3
Figure Lengend Snippet: Ectopic DKK1 interrupts AER maintenance/ Axin2 expression in the little skate pectoral fin for up to 72 h. Compare left column with interrupted Axin2 expression near the Dkk1 soaked bead with the right column that shows stage-specific native expression with implantation of a control bead. Axin2 expression is depicted in the anterior pectoral fins of little skate embryos at stages 30 ( A , B ; G , H ) and 31 ( C – F ; I , J ) of development after implantation of agarose beads soaked in DKK1 protein in the left fin (left column) and PBS in the right fin (right column) with the following incubation times: 6 h ( A , B ), 12 h ( C , D ), 24 h ( E , F ), 36 h ( G , H ) and 72 h ( I , J ). Comparisons between the DKK1 (left pectoral fin) and PBS control (right pectoral fin) beads illustrate treatment effects from implantations in the same individual. In some individuals ( C , D and G , H ), beads came out during the ISH process. Former location of beads is visible and denoted by blue dashed circles. Solid purple circles denote regions with Axin2 expression and dashed purple circles denote regions where Axin2 expression is expected but has been interrupted. For all incubation times, PBS beads had no effect on Axin2 expression. After 6 h, interruption of AER-associated Axin2 expression in the DKK1 treatment is clearly visible near the bead ( A , B ). After 12, 24, and 36 h incubation times, Axin2 expression in the anterior pectoral fins was completely interrupted. After 72 h of incubation ( I , J ), the effect of DKK1 inhibition on Axin2 is diminished but still visible near the bead, suggesting that the temporal scale of DKK1 protein activity is approximately 1–3 days. Axin2 expression in the posterior pectoral fins ( L , M ) was not affected in any individual regardless of treatment or incubation time, suggesting a spatial scale of approximately 1 cm from the implanted bead. Posterior pectoral fins at 24 hpi are depicted as this is when DKK1 reaches peak penetrance. Sense probe (see B ) showed no staining. Since embryos with different incubation times were at different developmental stages, the expected expression domain of Axin2 varies accordingly. Scale bar represents 1 mm
Article Snippet: O’Shaughnessy (personal communication) with the following modifications: Affigel-Blue (Bio-Rad, 1537302) beads were soaked overnight at 4 °C in DKK1 protein (mouse origin; R&D Systems, 5897-DK-010) reconstituted at 100 μg/mL in PBS containing 0.1% bovine serum albumin (BSA) or, as a control, in PBS containing 0.1% BSA.
Techniques: Expressing, Control, Incubation, Inhibition, Activity Assay, Staining