Expression of post-transcriptional regulatory gene of HTLV-I, rex, in Escherichia coli.

Human T-cell leukemia virus type-I (HTLV-I) has a post-transcriptional regulatory gene termed rex. We have designed the rex gene to express in E. coli. Synthesis of rex protein, p27rex, was examined by immunoblot analysis using anti-p27rex antibody. No difference in electrophoretic mobility in NaDadSO4-PAGE was observed between p27rex expressed in E. coli and in an HTLV-I-infected cell line, MT-2. Slower migration of p27rex, corresponding to a 27-kD protein, in NaDodSO4-PAGE when compared with the calculated molecular weight from the amino acid sequence (Mr = 20,367) is suggested to be caused not by post-translational modification, but by the intrinsic nature of the protein, which is rich in proline and arginine.