Methods for regulating gene expression

A method for regulating expression of a gene in a cell of a subject, comprising:

• 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 fusion protein which activates transcription, the fusion protein comprising a first polypeptide which binds to a tet operator sequence in the presence of tetracycline or a tetracycline analogue operatively linked to a second polypeptide which activates transcription in eukaryotic cells, 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 such that expression of the gene which is operatively linked to at least one tet operator sequence is regulated in a cell of the subject.

An isolated recombinant vector for coordinate, bidirectional transcription of a first and a second nucleotide sequence, the vector comprising a nucleotide sequence comprising in a 5' to 3' direction:

• a) a first cloning site for introduction of a first nucleotide sequence to be transcribed, operatively linked to
• b) at least one tet operator sequence, operatively linked to
• c) a second cloning site for introduction of a second nucleotide sequence transcribed,
• the vector further comprising additional regulatory sequences such That the vector is sufficient for use in eukaryotic cells, wherein transcription of a first and second nucleotide sequence introduced into the vector proceeds in opposite directions relative to the at least one tet operator sequence.