Provided are compositions and methods for silencing suppressor tRNAs. Further provided are compositions and methods for silencing suppressor tRNAs during AAV production for producing virions comprising sequences coding for suppressor tRNAs.

The present disclosure provides systems, methods, and compositions for conditionally regulating expression of a target gene. Aspects of the present disclosure utilize intracellular signal transduction pathways to regulate the expression of a gene (e.g., transgene, exogenous gene, endogenous gene).

Provided is a modular construction of synthetic gene circuits in mammalian cells using TALE transcriptional repressors. Provided is a method for achieving regulated expression of two proteins: an expression cassette A comprises a feedback element coding sequence, a promoter A, a protein A and TALER protein A encoding gene linked by means of a self-cleaving polypeptide, and a target sequence A (comprising an shRNA1 target sequence); an expression cassette B comprises a feedback element coding sequence, a promoter B, a protein B and TALER protein B encoding gene linked by means of a self-cleaving polypeptide, and a target sequence B (comprising an shRNA2 target sequence); an expression cassette C comprises a constitutive promoter and an activating element-coding sequence; a recombinant vector A having the expression cassette A, a recombinant vector B having the expression cassette B, and a recombinant vector C having the expression cassette C are introduced into host cells to regulate the expression of protein A and protein B by adding shRNA1 or shRNA2.

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 invention relates to gene therapy systems designed for the delivery of a therapeutic product to a subject using replication-defective virus composition(s) engineered with a built-in safety mechanism for ablating the therapeutic gene product, either permanently or temporarily, in response to a pharmacological agentpreferably an oral formulation, e.g., a pill. The invention is based, in part, on the applicants' development of an integrated approach, referred to herein as PITA (Pharmacologically Induced Transgene Ablation), for ablating a transgene or negatively regulating transgene expression. In this approach, replication-deficient viruses are used to deliver a transgene encoding a therapeutic product (an RNA or a protein) so that it is expressed in the subject, but can be reversibly or irreversibly turned off by administering the pharmacological agent; e.g., by administration of a small molecule that induces expression of an ablator specific for the transgene or its RNA transcript.

Genetically engineered bacteria which express RNAs or proteins that produce ammonia upon decreases in phosphate concentrations are disclosed.

Engineered bacteriophages comprising polynucleotides encoding heterologous proteins under the control of repressible promoters are provided. Also disclosed are processes for producing the engineered bacteriophages, pharmaceutical compositions comprising the engineered bacteriophages and therapeutic and preventive methods using the engineered bacteriophages.

The invention relates to the production and use of Cas-encoding sequences and vectors comprising these. Aspects of the invention provide products, vectors, delivery vehicles, uses and methods for producing Cas-encoding sequences in bacterial or archaeal cells.

The present application relates to a lentivirus vector with controllable expression of a gene of interest, and a packaging method therefor. The lentivirus packaging vector contains a first LTR, a reversely inserted gene expression cassette and a second LTR, wherein the first LTR is positioned upstream of the reversely inserted gene expression cassette in the direction of viral genome expression; the second LTR is positioned downstream of the reversely inserted gene expression cassette in the direction of viral genome expression; the gene expression cassette contains a promoter, a repressible operon and an optional gene of interest, which are connected in sequence; and in the presence of a repressor, the repressible operon is capable of repressing the expression of the gene of interest positioned downstream thereof.

An epigenetic silencer factor (ESP), or polynucleotide encoding therefor, for use in the treatment of cancer, wherein the ESF comprises a transcription factor DNA-binding domain operably linked to at least one epigenetic effector domain, wherein the transcription factor is an oncogenic transcription factor or a cancer-associated transcription factor, wherein the cancer is selected from the group consisting of: glioma, gliobastoma, medulloblastoma, astrocytoma, neuroblastomas, ependymoma, meningioma, retinoblastoma, rhabdomyosarcoma, lung cancer, prostate cancer, breast cancer, liver cancer, pancreatic cancer (e.g. human pancreatic ductal adenocarcinoma), bladder cancer, oropharyngeal cancer, kidney cancer, colon cancer (e.g. colon adenocarcinoma), colon-rectal cancer (CRC), or a metastasis of any of the foregoing.