Figure 4
Biomolecular fluorescence complementation (BiFC) assays reveal an in vivo interaction between CNG-3 with TAX-2 and CNG-3 with TAX-4. The cartoon at the top illustrates the orientation of the animal for all image panels with anterior to the left and the position of the AWC neuron cell body indicated. All images were captured using a confocal microscope (Zeiss) at 63X magnification. The cartoon on the right of each image indicates the CNG channel subunit pairing that is being tested. For all BiFC experiments, the CNG channels subunit are exclusively expressed in the AWC neurons. The first microscope image tests an in vivo interaction between TAX-2 tagged with the N-terminal of fluorescent Venus and also TAX-2 tagged with the C-terminal of fluorescent Venus. No interaction was observed using the TAX-2::VN173 and TAX-2::VC155 pairing. Next, a similar experiment was performed using TAX-4 tagged with the N-terminal of Venus and TAX-4 tagged with the C-terminal of Venus. In this case a signal was detected in the AWC cell body indicated by a white arrow-head (39% of the transgenic animals exhibited the BiFC signal). In the next combination the pairing of TAX-4 tagged with the N-terminal of Venus and TAX-2 tagged with the C-terminal of Venus was tested, and again a signal was detected in the cell body of AWC (22% of the transgenic animals exhibited the BiFC signal). Next an in vivo interaction was assayed between CNG-3 tagged with the C-terminal of Venus and TAX-4 with the N-terminal of Venus, and a robust signal was observed in the cell body and dendrite of AWC (61% of the transgenic animals exhibited the BiFC signal). Finally, the pairing of CNG-3 tagged with the C terminal of Venus and TAX-2 tagged with the N-terminal of Venus was tested and again a string signal was observed in the cell body and dendrite of the AWC neuron indicated by the white arrow (43% of the transgenic animals exhibited the BiFC signal).
