Figure 1

Expression of Mab21l2 gene and protein in Xenopus laevis development. A) Double whole mount in situ hybridization for Xmab21l2 (blue) and Xkrox20 (brown). At the end of neurulation (dorsal view of a st. 19 embryo is shown) Xmab21l2 expression (arrows) is restricted to the eye primordium (bottom arrowhead) and midbrain (top arrowhead). Xkrox20 labels the third and fifth rhombomeres (arrows). B) Frontal view of a stage 24 embryo. Xmab21l2 expression (blue, arrows) is restricted to the eye (left, solid arrow) and midbrain (right, solid arrow), clearly posterior to the forebrain marker Emx2 expression domain (brown, empty arrow). C–E: Sections obtained from late tadpole embryos were wholemount-hybridized with Xmab21l2. Three transverse sections, from anterior to posterior, show Xmab21l2 expression in the retina and lens (Ey), in the branchial arches (BA), midbrain (arrow in C), hindbrain (arrow in D), and in the dorsal neural tube, (SC in E). F: Western blot analysis of MAB21l2 protein expression in Xenopus oocytes (stage 0) and Xenopus embryos (stages 3–23). ME: day 12 mouse embryo (positive control). Protein concentrations were quantitated through a Bradford assay and loaded on gel in equal amounts. The experiment shows maternal expression of MAB21l2 (41 kD, arrow), the levels of which decrease around blastula stage to resume zygotically thereafter. In particular, stage 11 gastrulae are positive for the MAB21l2 protein.