Co-immunoprecipitation of LET-756::GFP and HA-tagged protein partners Cos-1 cells were transfected with let-756::gfp alone (0) and with various HA-tagged constructs presumed or not (TACC1) to interact with LET-756. Twenty four hours later cell lysates were immunoprecipitated with anti-GFP antibodies. Western blots were first revealed with anti-HA antibodies and then with anti-GFP antibodies. An additional band, indicated with an asterisk, was consistently observed with HA- tagged RPL-6. A week and non- reproducible band can also be seen in the FTT-2 co-immunoprecipitation lane. None of these bands arose from possible complexes since 1) electrophoresis was performed in denaturating conditions and 2) antibody detection relied on the tag epitope and not on the endogenous protein.