Fig. 3. SYCE1 and CESC1 interact with SYCP1, with each other and themselves. (A) Co-immunoprecipitation of SYCE1 with SYCP1. Testis extracts were incubated with affinity-purified anti-SYCP1, with pre-immune serum or with anti-SYCP1 and 50 ng of immunizing peptide. Complexes were recovered with protein G sepharose and analysed by western blots using anti-SYCE1 primary antibody. (B) Interaction of SYCE1 and CESC1 with SYCP1. ³⁵S-labelled protein corresponding to the N-terminal 200 aa of SYCP1 was incubated with glutathione sepharose beads with bound glutathione-S-transferase (GST), CESC1-GST or SYCE1-GST as indicated. In contrast to GST alone, the GST fusion proteins were able to bind the N-terminal region of SYCP1. (C) SYCE1 and CESC1 homotypic and heterotypic interactions. ³⁵S-labelled SYCE1 or CESC1 were allowed to interact with sepharose beads bound to GST, SYCE1-GST or CESC1-GST fusion proteins. CESC1 interacts with SYCE1 and with itself; SYCE1 is also able to interact with itself.