Figure 3: SIX6OS1 interacts specifically with SYCE1.

(a–c) HEK 293T cells were transfected or co-transfected with the indicated expression vectors. Protein complexes were immunoprecipitated overnight with either an anti-Flag, anti-EGFP or anti-Myc antibody, and were analysed by immunoblotting with the indicated antibody. (a) SIX6OS1 co-immunoprecipitates (co-IP) with SYCE1 (as well as in the reciprocal IP) but not with either SYCP1, SYCE3, SYCE2 or TEX12. (b) SIX6OS1-Flag co-immunoprecipitates with SIX6OS1-GFP, suggesting that it is able to form at least dimers. (c) SYCE1 co-immunoprecipitates with the SIX6OS1 N-terminal half (1–286) but not with the C-terminal half (287–574). Immunoprecipitation of SYCE1 and full length SIX6OS1 was used as positive control. (d) COS7 cells were transfected with Six6os1 alone (left panel) or in combination with Sycp1 and Syce1 (right panel). SIX6OS1 localization drastically changed in the presence of SYCE1 but not with SYCP1. (e) Sycp1, Syce3, Syce1 and Six6os1 were simultaneously co-transfected in COS7 cells and found to co-localize in the cytoplasm in the punctate pattern of SYCE1. The experiments were reproduced three times. Scale bars, 15 μm.