A conditional rescue system generally includes a gene transfer system, a polynucleotide including a nuclease-resistant target coding region, and a coding region encoding a conditionally-lethal polypeptide. The gene transfer system is effective to integrate into host cell DNA. The polynucleotide including the nuclease-resistant target coding region is under transcriptional control of an inducible promoter. The coding region encoding a conditionally-lethal polypeptide is transcriptionally linked to the target coding region.

The present invention provides a method and components thereof of performing genetic modification under a drug-free environment. The method comprises the steps of generating a trapped mammalian cell library by trapper constructs (including the element of piggyBac terminal inverted repeats (TIRs)), reporter constructs, and helper constructs (including a sequence of an internal ribosomal entry site (IRES)). The present art allows: (1) to target & identify the silenced loci; (2) to separate genes with low-level expression at certain differentiation stages; (3) to evaluate the efficiency of gene targeting in the silent or repressed loci. The present invention avoids the biased gene targeting observed in the prior arts, and eliminates the needs of introducing antibiotic genes into the host genome which may lead to a potential threat of drifting antibiotic resistant genes into environment.

The present invention provides a transposon for use in genetic manipulation of vertebrate and invertebrate cells.

The present invention is directed to nucleic acid and amino acid sequences of a novel piggyBac transposase enzymes created by modifying the transposase of Trichoplusia ni. The piggyBac transposases of the present invention are functionally active or hyperactive for excision and have decreased integration activity compared to wild type Trichoplusia ni piggyBac transposase enzyme. These transposases are ideal for use in methods of transforming cells and organisms. In particular embodiments, the present invention provides methods of transient integration and expression of transgenes.

The invention provides expression vectors for expressing recombinant proteins (e.g., biologics) in mammalian cells. Also provided are host cells comprising the expression vectors, methods of producing the recombinant proteins, and methods of propagating the expression vectors.

The invention provides inducible promoter systems and their components incorporating components of a tetracycline operon. By coordinating expression of different transcriptional units in these systems as a result of selection of promoters and/or linking the units into the same DNA molecule, these systems can achieve higher levels of expression of coding segments of interest, increased differential levels of expression between on- and off-states, and/or greater responsiveness to inducing agents than conventional systems.

This invention relates to a method for producing a protein of interest, comprising introducing a protein expression vector which comprises a gene fragment a gene fragment comprising a DNA encoding a protein of interest and a selectable marker gene and transposon sequences at both terminals of the gene fragment, into a suspension mammalian cell; integrating the gene fragment inserted between a pair of the transposon sequences, into a chromosome of the mammalian cell to obtain a mammalian cell capable of expressing the protein of interest; and suspension-culturing the mammalian cell; and a suspension mammalian cell capable of expressing the protein of interest.

Provided herein are methods for facilitating or inducing stable transgene integration and expression in a proliferating cell, comprising administering to the cell (i) a recombinant AAV (rAAV) vector comprising the transgene flanked by transposon-derived inverted terminal repeat sequences, which sequences are in turn flanked by AAV-derived inverted terminal repeat regions, and (ii) a source of a transposase that recognises said transposon-derived inverted terminal repeat sequences and directs the genomic integration of the transgene into the genome of the proliferating cell. Also provided are methods and transgene delivery systems for the treatment or prevention of diseases affecting, associated with or characterised by proliferating cells, including paediatric liver diseases, bone marrow diseases and cancer.

Provided are cells, tissues, organs, and/or animals having one or more modified genes for enhanced xenograft survival and/or tolerance. And methods of producing and using the cells, tissues, organs, and/or animals.

Disclosed are compositions comprising a first nucleic acid sequence comprising: (a) a first inverted terminal repeat (ITR), (b) a second ITR and (c) an intra-ITR sequence, wherein the intra-ITR sequence comprises a transposon sequence, and a second nucleic acid sequence comprising an inter-ITR sequence, wherein the length of the inter-1TR sequence is between 1 and 600 nucleotides, inclusive of the endpoints. Preferably, the compositions are nanotransposons.