Figure 4.

Reporter GFP expression studies for three X-box containing genes. (a) Stereotypical arrangement of type I sensory neurons in a Drosophila embryo, anterior to the left, stained with the 21A6 antibody with a magnification of the dorsal and lateral neurons of one abdominal segment as visualized in (f,k). The arrowhead indicates the five lateral chordotonal neurons (ch) and the arrows point to the neurons of the external sensory (es) organs. (b) Schematic of two typical chordotonal organs of Drosophila. (c-l) Confocal imaging of GFP expression of transgenic lines carrying the promoter region and coding sequences fused to the GFP for CG6129/rootletin (c-e), CG31036 (f-h) and CG13125/TbCMF46 (k,l). GFP expression is only observed in ciliated sensory neurons of D. melanogaster where the chimeric GFP proteins are localized to the ciliary apparatus. (c) CG6129::GFP reporter expression (green) is observed in embryonic chordotonal organs, mainly along the dendrite from the base of the cilium to the cell body. The 21A6 antibody (red, see Materials and methods) labels the ciliary dilation of the cilium. (d,e) Live GFP imaging of the lateral pentascolopidial chordotonal organs in male third instar larvae of dRfx deficient (e) and control (d) sibs. The elav-RFP expression (red) labels all neurons. CG6129/rootletin is regulated by dRfx as no GFP expression is observed in dRfx deficient larvae. (f-h) CG31036::GFP reporter expression (green) is observed both in the external sensory neurons (arrows in (f)) and the chordotonal neurons in the embryo (arrowhead in (f-h)). The 21A6 antibody (red) labels the ciliary dilation at the tip of the dendrite. CG31036::GFP protein localization appears to be slightly different depending on the fixative used (paraformaldehyde in (g), methanol in (h)). (i-j) Immunodetection of CG31036::GFP expression in leg chordotonal organs of 72-hour pupae in dRfx deficient (j) or control (i) sibs. The anti-ELAV antibody (red) labels all neurons. No CG31036::GFP expression is observed in dRfx deficient pupae (j). (k,l) CG13125::GFP expression is observed by immunodetection in the embryonic chordotonal organs (arrowheads in (k,l)) but also in the external sensory neurons (arrows in (k)). A higher magnification of the lateral chordotonal organs (l) shows that GFP is apposed to the 21A6 immunostaining (red). Scale bar = 10 μm.