A method for regulating expression of a tet operator-linked gene in a cell of
a
subject is disclosed. In one embodiment, the method involves introducing into the
cell a nucleic acid molecule encoding a tetracycline-controllable transactivator
(tTA), the tTA comprising a Tet repressor operably linked to a polypeptide which
directly or indirectly activates transcription in eucaryotic cells; and modulating
the concentration of a tetracycline, or analogue thereof, in the subject. Alternatively,
in another embodiment, the method involves obtaining the cell from the subject,
introducing into the cell a first nucleic acid molecule which operatively links
a gene to at least one tet operator sequence, introducing into the cell a second
nucleic acid molecule encoding a tTA, to form a modified cell, administering the
modified cell to the subject, and modulating the concentration of a tetracycline,
or analogue thereof, in the subject. The first and second nucleic acid molecule
can be within a single molecule (e.g., in the same vector) or on separate molecules.
