The invention provides a method of propagating an adenoviral vector. The method comprises (a) providing a cell comprising a cellular genome comprising a nucleic acid sequence encoding a tetracycline operon repressor protein (tetR), and (b) contacting the cell with an adenoviral vector comprising a heterologous nucleic acid sequence encoding a toxic protein. The heterologous nucleic acid sequence is operably linked to a promoter and one or more tetracycline operon operator sequences (tetO), and expression of the heterologous nucleic acid sequence is inhibited in the presence of tetR, such that the adenoviral vector is propagated. The invention also provides a system comprising the aforementioned cell and adenoviral vector.

The invention relates to retroviral producer cells comprising nucleic acid sequences encoding: gag and pol proteins; envelope protein or a functional substitute thereof; and the RNA genome of the retroviral vector particle, wherein the nucleic acid sequences are all located at a single locus within the retroviral producer cell genome.

The invention relates to retroviral producer cell comprising nucleic acid sequences encoding: gag and pol proteins; envelope protein or a functional substitute thereof; amplifiable selection marker; and the RNA genome of the retroviral vector particle, wherein said nucleic acid sequences are all integrated at a single locus within the retroviral producer cell genome. The invention also relates to nucleic acid vectors comprising a non-mammalian origin of replication and the ability to hold at least 25 kilobases (kb) of DNA, characterized in that said nucleic acid vector comprises retroviral nucleic acid sequences encoding: gag and pol proteins, and an env protein or a functional substitute thereof. The nucleic acid vector additionally comprises nucleic acid sequences encoding an amplifiable selection marker. The invention also relates to uses and methods using said nucleic acid vector in order to produce stable retroviral packaging and producer cell lines.

Described herein are methods and compositions for autocatalytic genome editing and neutralizing autocatalytic genome editing. The autocatalytic genome editing may be based on genomic integration of a construct containing multiple elements or on a trans-complementation approach, in which genetic elements can be propagated separately. The disclosure provides a method for autocatalytic genome editing based on the CRISPR/CAS9 system, and methods of use thereof, in animals, humans, and plants for eliminating pathogens, targeting suppression of crop pests, strategies to combat virus (e.g., HIV) and other diseases (e.g., cancer) caused by retrovirus, as well as to generate homozygous mutations that are transmitted to nearly all offspring.

The present invention provides compositions and methods for programming mammalian cells to perform desired functions. In particular, the present invention provides compositions and methods for programming stem cells to differentiate into a desired cell type. A quorum sensing systems that regulates the expression of cell fate regulators is introduced into mammalian host cells, such as stem cells. The quorum sensing systems generally comprises vectors that express the components of a bacterial quorum sensing pathway, including proteins which catalyze the synthesis of an autoinducer and a gene encoding a regulatory partner of the autoinducer, and vectors in which genes encoding cell fate regulators are operably linked to a promoter induced by the autoinducer/regulatory partner complex. The system can also comprise vectors in which genes encoding additional cell fate regulators are operably linked to a promoter that is induced by a factor synthesized in response to a first stage of differentiation, so that a second stage of differentiation is triggered.

The present disclosure relates to genetically modified conditionally immortalized cells and cell lines, provided with a vector comprising a promoter sequence, at least one immortalization gene operably linked to the promoter sequence, a gene coding for an inducible regulator operably linked to the promoter sequence and a response element for the inducible regulator. The present disclosure further relates to methods for their preparation, and to immortalization and differentiation of such cells.

Provided are a stable lentivirus packaging cell line and a preparation method therefor. The stable lentivirus packaging cell line contains a packaging plasmid group consisting of a pPuro.coTetR plasmid, a pVSVG plasmid, and a pGagPol-RRE-NES-cINT plasmid, wherein the pPuro.coTetR plasmid contains a CoTetR gene, the pVSVG plasnid contains a VSVG gene, and the pGagPol-RRE-NES-cINT plasmid contains GagPol and Rev genes. The stable lentivirus packaging cell line is relatively stable in terms of passage, virus production, and a genetic gene copy number, and the lentivirus produced by using the stable lentivirus packaging cell line has a high titer and a low impurity content.

The invention provides methods for reprogramming somatic cells to generate multipotent or pluripotent cells. Such methods are useful for a variety of purposes, including treating or preventing a medical condition in an individual. The invention further provides methods for identifying an agent that reprograms somatic cells to a less differentiated state.

The invention provides methods for reprogramming somatic cells to generate multipotent or pluripotent cells. Such methods are useful for a variety of purposes, including treating or preventing a medical condition in an individual. The invention further provides methods for identifying an agent that reprograms somatic cells to a less differentiated state.

The disclosure relates to a method of reprogramming one or more somatic cells, e.g., partially differentiated or fully/terminally differentiated somatic cells, to a less differentiated state, e.g., a pluripotent or multipotent state. In further embodiments the invention also relates to reprogrammed somatic cells produced by methods of the invention, to uses of said cells, and to methods for identifying agents useful for reprogramming somatic cells.