Producer cell and packaging cell for retroviral vector and preparation method thereof

A method for preparing a producer cell for producing a retroviral vector carrying a nucleic acid fragment of interest, comprising:

• integrating one or more but not all of
• sequences of gag and pol genes of a retrovirus,
• a coding sequence of a viral envelope protein, and
• a viral genome transcriptional cassette sequence carrying the nucleic acid fragment of interest into the genome of a host cell using a Sleeping Beauty (SB) transposon system, and further integrating the remaining one or more of
• the sequences of gag and pol genes of the retrovirus,
• the coding sequence of the viral envelope protein, and
• the viral genome transcriptional cassette sequence carrying the nucleic acid fragment of interest into the genome of the host cell using a PiggyBac (PB) transposon system;
• or
• integrating one or more but not all of
• sequences of gag and pol genes of a retrovirus,
• a coding sequence of a viral envelope protein, and
• a viral genome transcriptional cassette sequence carrying the nucleic acid fragment of interest into the genome of a host cell using a PB transposon system, and
• further integrating the remaining one or more of
• the sequence of gag and pol genes of the retrovirus,
• the coding sequence of the viral envelope protein, and
• the viral genome transcriptional cassette sequence carrying the nucleic acid fragment of interest into the genome of the host cell using a SB transposon system;
• controlling the transcription of i) one or more of the gag, pol and rev genes and ii) the coding sequence of the viral envelope protein, via a combination inducible expression system comprising a Tet-On inducible expression system and a Cumate inducible expression system;
• and
• independently controlling the transcription of the viral genome transcriptional cassette carrying the nucleic acid fragment of interest via a Tet-On inducible expression system.