Figure 1
From: The Drosophila immunoglobulin gene turtle encodes guidance molecules involved in axon pathfinding
Genomic organization and in situ expression of the turtle gene. (A) Schematic diagram showing intron-exon structure of turtle transcripts, the proteins that they encode (color-coded to show only clearly defined protein domains shared between the different isoforms), the span of the tutlex383and tutl4deletion, and the two P-element insertions. (B) Western blot against the His-tagged diffusible GH015753-encoded isoform of turtle protein expressed in S2 cells. After transfer, both samples were examined on the filter by Ponceau S staining, and although there was abundant protein in both lanes, most of the His-tagged protein was found in the supernatant (2), not the cell pellet (1). Similar results were obtained using the His-tagged AT02763-encoded diffusible isoform of turtle protein (data not shown). (C) RT-PCR showing low expression of the AT0276 and HL01565 isoforms in stage 12/13 embryos compared to GH015753, LD2884, and GH08133 isoforms. (D, E) RNA in situ hybridization against the domains shared by all isoforms indicates that turtle is initially expressed close to the midline in embryonic stages 12 to 13 (D, arrow), with later expression spreading throughout the central nervous system (E, arrow). (F) RNA in situ hybridization of GH015753 (red), LD2884 (green), and GH08133 (blue) isoforms indicates overlapping nervous system expression in stage 13/14 embryos (arrow), with some expression of LD28224 and GH08133 in salivary gland (asterisk) and gut (arrowhead). (G-J) Staining with the neuronal marker anti-Elav (G, I, red) indicates that both GH015753 and LD2884 (G-I, green) are expressed in neuronal cells. Both isoforms also co-localized with some anti-Repo-positive glial cells (H, J, red). (K) RNA in situ hybridization in wandering third larval instar eye discs indicates that all isoforms are expressed in the morphogenic furrow (asterisk), with some cells at the tip of the eye disc expressing only GH015753 (arrow), which are surrounded by cells expressing only LD28224 (arrowhead). (L) RNA in situ hybridization in wandering third larval instar brains indicates strong, overlapping expression of the turtle isoforms throughout the optic lobe, with some cells in the optic lobe-retinal nerve junction expressing only the LD2884 isoform (arrow).