Abstract: The invention relates to an expression system which permits control of the levels of protein produced, and optionally provides production of the mature form of the protein directly. The expression systems of the invention include the desired gene downstream of a first DNA which comprises the reverse transcript of an inducible translational regulator and a second DNA which is the reverse transcript of an mRNA capable of self-stabilization. This translated sequence is in turn under the control of a transcriptional promoter which may also be inducible. In a preferred embodiment, the inducible translational regulator is the iron responsive element (IRE) region of ferritin mRNA, and the stabilizing element is also a portion of the ferritin sequence. The expression system is useful, especially, for the production of toxic proteins since protein production can be delayed until desired.

Abstract: The invention relates to an expression system which permits control of the levels of protein produced, and optionally provides production of the mature form of the protein directly. The expression systems of the invention include the desired gene downstream of a first DNA which comprises the reverse transcript of an inducible translational regulator and a second DNA which is the reverse transcript of an mRNA capable of self-stabilization. This translated sequence is in turn under the control of a transcriptional promoter which may also be inducible. In a preferred embodiment, the inducible translational regulator is the iron responsive element (IRE) region of ferritin mRNA, and the stabilizing element is also a portion of the ferritin sequence. The expression system is useful, especially, for the production of toxic proteins since protein production can be delayed until desired.