Gene expression control system and its use in recombinant virus packaging cell lines

A cell or cell line comprising a nucleic acid comprising a gene having an intron comprising a disruptable transcription termination sequence.

A transgenic non-human animal comprising a nucleic acid comprising a target gene having an intron positioned in an expressed sequence of the target gene, the intron comprising a disruptable transcription termination sequence.

A method for expressing a gene in a cell, comprising the step of contacting a nucleic acid in a cell comprising an inactivated target gene having an intron comprising an disruptable transcription termination sequence with a trans-acting agent for disrupting the transcription termination sequence.

A method for producing a recombinant AAV particle, comprising the step of introducing a recombinase enzyme into a cell containing:

• (a) a first nucleic acid sequence comprising AAV sequences encoding AAV Rep and Cap genes, wherein the Rep gene contains an intron positioned in a coding sequence shared by Rep78, Rep68, Rep52 and Rep40 proteins, the intron comprising a transcription termination sequence flanked by a pair of recombination sites;
• and
• (b) a template for a packageable rAAV genome.

A method for producing recombinant parvovirus particles, comprising the step of introducing a recombinase enzyme into a cell containing:

• (a) a first nucleic acid sequence comprising sequences for a parvovirus non-structural gene encoding two or more proteins from a shared reading frame, and any additional parvovirus proteins necessary in trans for production of recombinant parvovirus transducing unit, wherein the non-structural gene contains an intron positioned in the shared reading frame of the non-structural gene, the intron comprising a transcription termination sequence flanked by a pair of recombination sites;
• and
• (b) a template for a packageable recombinant parvovirus genome.

An isolated and purified nucleic acid comprising an intron comprising a disruptable transcription termination sequence.

A cell or cell line comprising a nucleic acid comprising a gene having an intron comprising an excisable transcription termination sequence.

A method for expressing a gene in a cell, comprising the step of contacting a nucleic acid in a cell comprising an inactivated target gene having an intron comprising an excisable transcription termination sequence with a trans-acting agent for excising the transcription termination sequence.