Figure 6
Vari interacts with NrxIV in vitro and in vivo. (A) A GST-NrxIV fusion protein comprising the entire intracellular domain of NrxIV (including the PDZ-binding motif-EIFI) pulls down a His-tagged Vari transgene that contains only the PDZ domain (Pro169-Val270) in vitro. However, a GST-NrxIV fusion protein including a C-terminally truncated intracellular domain of NrxIV (lacking the PDZ-binding motif-EIFI) does not. (B) Co-immunoprecipitation assay from embryonic protein extracts (> 8 h; genotype: NrxIV-GFP/TM6B) reveals that in the embryo NrxIV forms a complex with Vari-long and Vari-short. (C) Both GST-DLin-7 and GST-DLin-7-L27 fusion protein (containing only the L27 domain of DLin-7), pull down the His-tagged Vari N-terminus (Ser5-Tyr157), which comprises the putative L27 domains, while GST-DLin-7-PDZ fails to pull down Vari. (D-G) Wild-type embryos of stage 15 overexpressing different UAS-transgenes in a striped pattern using enGal4. Green: anti-Vari, Red: anti-NrxIV (D, F); Green: anti-Vari, Red: anti-Dlg (E); Green: anti-Vari, Red: anti-DLin-7 (G). Recruitment of Vari by ectopic NrxIV is specific. In D-G apical is up.