In this vein, we present CTLAP, a fluorogenic probe that is rapidly activated by CTL and displays good selectivity over CTB and CTV, the closest competing analytes for CTL activity probes. CTLAP exhibits intrinsically low background fluorescence, which we attribute to the notably low quantum yield measured for the probe. CTLAP demonstrates markedly higher turn-on ratios (24-fold) and moderately improved enzyme selectivity (6- to 10-fold) when compared to Z-FR-AMC (10-fold turn-on ratio, 6- to 7-fold selectivity), a commercially available CTL-selective probe commonly used to detect CTL activity in mixed samples. Optimum selectivity for CTL is achieved within 10 min of incubation with the enzyme, suggesting that CTLAP is amenable for rapid detection of CTL, even in the presence of competing cathepsins.

The present disclosure provides novel compositions and methods suitable for specifically eliminating target cells (e.g., cancer cells) without affecting non-target cells (e.g., non-cancer cells). For example, CR-ISPR system and the compositions of the present disclosure can be employed to specifically introduce a suicidal gene into a cancer cell in the loci of a cancer-specific target sequence, which as a result of chromosomal re-arrangement or translocation in a cancer cell presents a cancer specific sequence for a guide RNA and CAS to be recognized and such sequence is absent in a non-cancer cell. Consequently, the specific introduction of the composition(s) to cancer-specific site(s) and integration of suicide gene in the target genome, which is inapplicable to normal cells for lack of the site(s), leads to selective elimination of cancer cells but not non-cancer cells, and therefore render novel therapeutic methods and compositions for cancer treatment.

The present invention provides a chimeric protein having the formula: Casp-Ht1-Ht2 wherein Casp is a caspase domain; Ht1 is a first heterodimerization domain; and Ht2 is a second heterodimerization domain and wherein, in the presence of a chemical inducer of dimerization (CID), an identical pair of the chimeric proteins interact such that Ht1 from one chimeric protein heterodimerizes with Ht2 from the other chimeric protein, causing homodimerization of the two caspase domains. The invention also provides a cell comprising such a protein and its use in adoptive cell therapy.

Some aspects of this disclosure provide strategies, systems, reagents, methods, and kits that are useful for the targeted editing of nucleic acids, including editing a single site within the genome of a cell or subject, e.g., within the human genome. In some embodiments, fusion proteins of Cas9 and nucleic acid editing enzymes or enzyme domains, e.g., deaminase domains, are provided. In some embodiments, methods for targeted nucleic acid editing are provided. In some embodiments, reagents and kits for the generation of targeted nucleic acid editing proteins, e.g., fusion proteins of Cas9 and nucleic acid editing enzymes or domains, are provided.

A composition comprising an expression cassette having a nucleic acid sequence encoding one or more elements of a gene editing system that targets UBE3A-ATS on a paternal allele in a neuron of a patient having Angelman syndrome is provided. Also provided is a method for treating one or more symptoms of Angelman syndrome (AS) in a patient having deficient UBE3A expression in neurons, wherein the method comprises delivering a nucleic acid sequence that encodes one or more elements of a gene editing system that targets UBE3A-ATS to modify the UBE3A-ATS coding sequence and provide for expression of paternal UBE3A.

The present application relates, in some aspects, to the development of an assay that uses cell survival and/or cell viability as a phenotypic identifier to positively select for agents that destabilize a protein of interest.

Herein is reported a method for producing an enzymatic conjugation product of two polypeptides comprising incubating of a first polypeptide comprising the amino acid sequence LPXTG (SEQ ID NO: 20, wherein X can be any amino acid residue), a second polypeptide has an oligo-alanine A.sub.m (m=2 (SEQ ID NO: 26), or 3 (SEQ ID NO: 27), or 4 (SEQ ID NO: 28), or 5 (SEQ ID NO: 29)) amino acid sequence at its N-terminus, a third polypeptide with sortase activity which is derived from Staphylococcus aureus Sortase A, and recovering the conjugate from the reaction mixture and thereby producing the enzymatic conjugation product of two polypeptides.

Methods and combinations are provided for controlling the duration of action, in vivo, of matrix-degrading enzymes. The methods and combinations permit temporary in-vivo activation of matrix-degrading enzymes upon administration to the extra cellular matrix (or “ECM”). Matrix-degrading enzymes having a controlled duration of action can be used to treat ECM-mediated diseases or disorders characterized by increased deposition or accumulation of one or more ECM components.

Chimeric antigen receptors (CARs) including an antigen binding domain specifically binding to coronavirus spike protein, nucleic acids encoding the CARs, vectors including nucleic acids encoding the CARs, and immune cells expressing the CARs are provided. Methods of treating a subject with coronavirus, including administering to the subject an immune cell expressing a disclosed CAR are also provided.

Disclosed herein are cells that are immune cells or precursor cells thereof, which cells recombinantly express a chimeric antigen receptor (CAR), and a dominant negative form of an inhibitor of a cell-mediated immune response of the immune cell, wherein the CAR binds to a cancer antigen. Also disclosed herein are T cells that recognize and are sensitized to a cancer antigen, which T cells recombinantly express a dominant negative form of an inhibitor of a T cell-mediated immune response. Additionally provided are methods of using such cells to treat cancer in a subject in need thereof.