Fig. 2.

Expression and detection of recombinant Tol2 transposase protein. a Tol2 transpoase sequence was cloned into an N-terminal 6XHis expression vector pET-21a (Novagen). The expression cassette driven by T7 promoter is shown, and a fusion protein of ~74 kD was expected. rbs: ribosome binding site. b Expression of His-Tol2 in E.coli BL21-AI strain. unind: cell lysate from uninduced cells harboring Tol2-expression vector; t: total induced crude cell lysate; i: insoluble protein fraction from induced cell lysate; s: soluble protein fraction from induced cell lysate. Equal volume of cell culture was loaded in each lane. p: ~ 350 ng purified His-Tol2 protein (arrow head). c Immunoblot analysis of His-Tol2 expression with anti-His antibody. The same protein samples as in (b) were loaded except that only ~ 6 ng purified His-Tol2 was used for detection by western blot