Endogenous ELL is in a complex with endogenous EAF1 in untransfected cells.

(A) The 293 cell extracts were immunoprecipitated with an isotype control antibody or with the EAF1 monoclonal antibody. Using an affinity-purified polyclonal ELL antibody, endogenous ELL was detected in the lysates precipitated by the EAF1 antibody but not in the lysates precipitated by the isotype control. As an additional control, the immunoprecipitates were also probed with the rabbit preimmune serum. (B) Endogenous ELL and EAF1 form a stable complex. The 293 cell extracts were immunoprecipitated with the EAF1 monoclonal antibody and washes were performed with increasing concentrations of SDS, NP-40, or NaCl. Washes with standard NETN are shown in the far right lane. The precipitated ELL protein was detected using the affinity-purified polyclonal ELL antibody. The ELL/EAF1 complex was stable in washes containing up to 2% NP-40 and 1.2 M NaCl. The complex began to dissociate in washes containing 0.5% SDS and was almost completely dissociated at 1% SDS.