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. Author manuscript; available in PMC: 2009 Aug 13.
Published in final edited form as: Curr Biol. 1999 Nov 4;9(21):1267–1270. doi: 10.1016/s0960-9822(99)80510-7

Figure 3.

Figure 3

Selective expression of TeTxLC in aCC neurons deprives them of synaptic input. (a) Expression pattern of RRC-GAL4 visualised by anti-β-galactosidase immunostaining in three abdominal segments of a late stage 17 embryo (20 h AEL). Two strongly stained aCC neurons are present in all three segments (arrows), whereas staining of RP2 is more variable (arrowheads) and pCC staining is weak (open arrowhead). Only one pCC cell is visible in the three segments shown. The scale bar represents 10 µm. The inset shows a diagrammatic representation of the relative positions of aCC, pCC and RP2 neurons in a single abdominal segment in a late stage 17 embryo. Neurons are shaded to reflect their levels of RRC-GAL4 expression. (b) Electrical stimulation of the axon of an aCC neuron that is expressing TeTxLC under the control of RRC-GAL4 failed to evoke an ejc in its target muscle DA1. Immunostaining of the terminals of aCC using an anti-Fasciclin II antibody revealed no obvious morphological abnormalities (data not shown). Synaptic communication between other motorneurons and their target muscles was not affected (RP3 and muscle VL3 are shown). The RRC-GAL4 line was used as control. (c) Selective expression of TeTxLC results in a significant reduction in the number of aCC neurons that exhibit epscs (white bars, +) compared with expression of inactive toxin (TNT-VIF). (d) The proportion of pCC neurons that exhibit epscs (white bars, +), and their frequency, does not differ significantly in embryos expressing either TeTxLC or TNT-VIF. (e) Expression of TeTxLC similarly results in a significant decrease in the number of aCC neurons that show sustained inward currents compared to TNT-VIF (white bars, +). (f) Expression of TeTxLC does not affect the appearance or frequency of sustained currents in pCC. In each case, the white bars represent those neurons in which these respective currents were observed (+) and the grey bars represent those neurons in which currents were not seen (−). In (c–f) the given values represent the frequency per min of observed currents ± SE.