Expression of biologically active human T-cell lymphotropic virus type III reverse transcriptase in Bacillus subtilis

A 2.4-kb DNA fragment from the pol region of the human T-cell lymphotropic virus, encoding the protease, reverse transcriptase and a portion of the endonuclease N-terminus was stably introduced into a high-level Bacillus subtilis expression system under inducible control of the Escherichia coli lac regulatory elements. The major expression plasmid, pRTL11, contains a bacteriophage T5 promoter/lac operator element, which is controlled by lac repressor, supplied by the secondary plasmid, pBL1. Upon IPTG induction, a 90-kDa polyprotein is synthesised and subsequently proteolytically cleaved to reveal 64-kDa and 52-kDa polypeptides. Partial purification reveals that reverse transcriptase activity co-migrates with these two polypeptides.