Siah targets Nlz2 for proteasomal degradation. (A) Conservation of Nlz2 ‘degron’ motif sequence. (B) Western blot analysis of nlz2-FLAG protein stability in response to siah1-myc, siah1ΔR-myc or siah1-myc+MG132. Actin was used as a loading control. * indicates potential ubiquitination products. Nlz2-FLAG band intensity quantification is shown. (C) Co-immunoprecipitation of nlz2-FLAG co-transfected with HA-ubiquitin, siah1-myc or siah1ΔR-myc probed for FLAG (green), MYC (red) and HA (B/W). * indicates potential ubiquitination. (D) Upper panels: endogenous Siah activity reporter assay expression in eyes of 24 hpf GFP-NxN or GFP-VSP mRNA-injected embryos, ±12.5 µM MG132. mCherry mRNA was co-injected for normalization. Scale bar: 50 µm. Lower panel: quantification of normalized GFP fluorescence intensity in the eye±s.d. *P<0.05 compared to GFP-NxN, #P<0.05 compared to GFP-VSP, one-way ANOVA; P<0.0001.
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