All embryos are wild type

(A–C) EMs of embryos in XS. (A) Early stage 16 embryo showing two CBs initiating contact at their dorsal leading edges (arrows). (B) At late stage16, the dorsal edge has made contact (asterisk) and the CBs are initiating contact ventrally (arrow). (C) At stage 17, the lumen (arrow) is formed between two contralateral CBs joined at dorsal and ventral attachment points (asterisks). (D) Schematic of the heart in XS showing CBs joined at dorsal and ventral attachments (arrows). (E–G) Confocal images of stage 16 embryos in a dorsal view. (E) Mef2 labels CB nuclei (magenta), and Slit (green) localizes to the apical side of CBs. (F) Mef2 (magenta) and Robo (green). Robo localizes to the apical side of CBs, alary muscles (asterisks), and PCs (arrow). (G) Mef2 (magenta) and Robo2 (green), which localizes to the PCs (arrow). (H) Schematic of the heart in dorsal view showing the position of CBs (green) and PCs (yellow). A single CB is shown making contact with one contralateral and two ipsilateral CBs (arrows). (I–K) XSs of stage 17 embryos stained with HRP (brown). (I) Slit accumulates at the apical surface of the lumen (arrow). (J) Robo localizes to apical lumenal surface and the alary muscles (asterisk). (K) Robo2 is restricted to the PCs (arrow). Bar, 2 μm.Copyright information:Taken from "Repulsion by Slit and Roundabout prevents Shotgun/E-cadherin–mediated cell adhesion during heart tube lumen formation"The Journal of Cell Biology 2008;182(2):241-248.Published online 28 Jul 2008PMCID:PMC2483515.