Expression of Sns and Kirre in embryonic GCNs. (A) Schematic,
modified with permission from Hartenstein
(Hartenstein, 1993) to
indicate the position of GCNs (yellow) at embryonic stage 16. (B-L)
GCNs were identified by expression of the sns-GCN-lacZ transgene. (B)
Ventral view, stage 16. (C-F) Confocal single section of GCNs at stage 13. Sns
(red) and Kirre (red) are present at cell-cell contacts (arrows). Arrow in B
indicates GCNs marked by β-galactosidase. (G-L) Ventral views, stage 16.
Projections of confocal sections (∼20 μM) (G,J) and single sections
(H,I,K,L) reveal Sns (H,I) and Kirre (K,L) on the cell surface (arrowheads),
cell-cell contacts (arrows) and in intracellular and cell surface puncta
(asterisks). Note the uneven pattern of Sns on the cell surface in (I).
(M-T) FACS-isolated nGFP-positive cells from sns-GCN-nGFP
transgenic embryos. Single confocal sections show partial co-localization of
Sns and Kirre on the surface of mononucleate (9-12 hours AEL) (M-P) and
binucleate (12-18 hours AEL) (Q-S) GCNs. Scale bars: 10 μm in C-L; 5 μm
in M-T. ES, esophagus; PV, proventriculus.