Fig. 7
Fig. 7 barx1 negatively regulates hand2. (A-F′′) Wild-type and barx1 mutant animals were subjected to fluorescent in situ hybridization to reveal sox9a, nkx3.2 and hand2 expression during the pharyngula (A-B′′) and hatching (C-F′′) periods. Arrow indicates ventrally restricted hand2; arrowhead indicates expanded hand2 expression. All panels are single confocal sections. (G,H) Animals were subjected to in situ hybridization to reveal midline-restricted hand2 expression in wild type (arrow) and expanded hand2 expression in barx1 mutants (arrowhead). (I,J) hand2-expressing cells were transgenically labeled with E2Crimson (hand2:Crimson, red) and chondrocytes with EGFP (sox9a:EGFP, green), and imaged by time-lapse microscopy. Movie excerpts are z-projections from the ventral perspective. Arrow indicates downregulated hand2 reporter in differentiated cartilages; arrowhead indicates persistent hand2 reporter. Dorsal is upwards and anterior is towards the left in A-D; anterior is towards the top, while right is towards the left in E-J. Scale bars: 100 μm.