[Prokaryotic expression and purification of human TLE1 N-terminal Q domain fragment and production of its polyclonal antibody].

Background: TLE1 is an important protein in regulating Wnt, Notch and EGFR signaling pathways. The TLE1 N-terminal Q domain regulates the pathways by mediating its oligomerization and interaction with LEF1. The aim of this study is to construct the human TLE1 N-terminal Q domain fragment in prokaryotic expression system, express and purify protein TLE1 N-terminal Q domain and prepare its polyclonal antibody.
Methods: The sequence of TLE1 N-terminal Q domain obtained by PCR from human lung adenocarcinoma cDNA, was cloned into the prokaryotic expression vector pGEX-4T-1 containing Glutathione S-transferase (GST). Vector pGEX-4T1-TLE1-Q was transformed into E.coli BL21 condon plus. The GST-TLE1-Q(1-136) fusion protein was induced by IPTG, digested by Thrombin, purified with glutathione-sepharose beads and FPLC, identified by SDS-PAGE. Then rabbits were immunized with the purified protein TLE1-Q(1-136) for obtaining the antiserum. The titers and specificity of antibodies were measured by ELISA and Western blot.
Results: The PCR identification and the sequencing of recombinant plasmid demonstrated that vector pGEX-4T1-TLE1-Q was successfully constructed. The SDS-PAGE shows target protein (14,000 Da) is the interest protein TLE1-Q(1-136). The TLE1 N-terminal Q domain fragment TLE1-Q(1-136) and its polyclonal antibody have been acquired, with an antibody titer of 1:20,000.
Conclusions: Expression vector pGEX-4T1-TLE1-Q is correctly constructed. The TLE1 N-terminal Q domain fragment TLE1-Q(1-136) and its polyclonal antibody have been acquired. These work established the foundation for further biological study between TLE1 and lung cancers.