The invention pertains to an inducible CRISPR system for controlling expression of a CRISPR complex with an inducible fusion promoter. One embodiment of the invention provides HIV LTR-minimal Drosophila hsp70 fusion promoter that can be used for inducible co-expression of gRNA and Cas9 in HIV-infected cells to target cellular cofactors such as Cyclin T1. A single introduction of such embodiment leads to sustained suppression of HIV replication in stringent, chronically infected HeLa-CD4 cell lines as well as in T-cell lines. In another embodiment, the invention further relates to enhancement of HIV suppression by incorporating cis-acting ribozymes immediately upstream of the gRNA in the inducible CRISPR system construct. The inducible fusion promoter is adaptable for other tissue- or cell-type specific expression of the inducible CRISPR system.

The invention pertains to an inducible CRISPR system for controlling expression of a CRISPR complex with an inducible fusion promoter. One embodiment of the invention provides HIV LTR-minimal Drosophila hsp70 fusion promoter that can be used for inducible co-expression of gRNA and Cas9 in HIV-infected cells to target cellular cofactors such as Cyclin T1. A single introduction of such embodiment leads to sustained suppression of HIV replication in stringent, chronically infected HeLa-CD4 cell lines as well as in T-cell lines. In another embodiment, the invention further relates to enhancement of HIV suppression by incorporating cis-acting ribozymes immediately upstream of the gRNA in the inducible CRISPR system construct. The inducible fusion promoter is adaptable for other tissue- or cell-type specific expression of the inducible CRISPR system.

The present invention provides for novel compositions and methods for delivering genes of interest to stem cells using vectors that contain differentiation-specific transcriptional regulatory elements. For example, stem cells in the internal epithelia could be transfected with a vaccine construct, which has an epithelial cell differentiation-specific promoter driving the expression of viral envelope proteins. When the promoter used is specific for terminally differentiated epithelial cells, then the viral envelope proteins will be expressed only in the upper part of the epithelia and therefore, stimulate the immune response. The infected epithelial stem cells in the basal layer will continue to produce new antigen-expressing cells, without being eliminated by the immune response. This invention will be useful in the development of vaccines against viral agents that target the internal mucosa like HIV.

The invention provides a method of viral transfection of cells.

The invention is directed to a system comprising a lentivirus vector particle which encodes at least one guide RNA sequence that is complementary to a first DNA sequence in a host cell genome, a Cas9 protein, and optionally a donor nucleic acid molecule comprising a second DNA sequence. The invention also is directed to a method of altering a DNA sequence in a host cell using such a system, where the host cell can be in a human and the altered DNA can be of the human β-globin gene. The invention also is directed to a fusion protein comprising a Cas9 protein and a cyclophilin A (CypA) protein. The invention also is directed to sequences of vectors that can be used in the system and method.

The invention pertains to an inducible CRISPR system for controlling expression of a CRISPR complex with an inducible fusion promoter. One embodiment of the invention provides HIV LTR-minimal Drosophila hsp70 fusion promoter that can be used for inducible co-expression of gRNA and Cas9 in HIV-infected cells to target cellular cofactors such as Cyclin T1. A single introduction of such embodiment leads to sustained suppression of HIV replication in stringent, chronically infected HeLa-CD4 cell lines as well as in T-cell lines. In another embodiment, the invention further relates to enhancement of HIV suppression by incorporating cis-acting ribozymes immediately upstream of the gRNA in the inducible CRISPR system construct. The inducible fusion promoter is adaptable for other tissue- or cell-type specific expression of the inducible CRISPR system.

An enveloped viral particle producer or packaging cell, wherein the cell is genetically engineered to decrease expression of MHC-I on the surface of the cell.

In accordance with the present invention, a method for increasing the yield of rLV vector particles comprising a trans gene encoding a therapeutic protein or fragment thereof is disclosed. In one approach, cells are transfected with plasmids encoding the necessary components for rLV production using a calcium chloride transfection mix at pH 7.1 wherein the calcium chloride and plasmids form a complex which is added to the cells at a constant speed. The cells are then incubated for a suitable time period wherein virus particle media is collected at least twice during the incubation period and stored in a cold storage unit, thereby reducing virus inactivation.

The present disclosure provides a method of generating a stable producer cell line. The generation of stable producer cell lines, such as those provided in accordance with the present invention, increases the reproducibility and ease of creating high titer lentiviral stocks while easing biosafety concerns and the variation in expressed envelope proteins defines the tropism of the generated virus. The present disclosure also provides for a novel lentiviral transfer vector plasmid.

The present disclosure provides a method of generating a stable producer cell line. The generation of stable producer cell lines, such as those provided in accordance with the present invention, increases the reproducibility and ease of creating high titer lentiviral stocks while easing biosafety concerns and the variation in expressed envelope proteins defines the tropism of the generated virus. The present disclosure also provides for a novel lentiviral transfer vector plasmid.