The disclosure provides compositions and methods for high-efficiency genome editing in mammals. In some aspects, the disclosure provides guide RNA-retron cassettes, RNA-guided nuclease (e.g., Cas9)-reverse transcriptase fusion protein encoding cassettes, and vectors comprising the cassettes. Also provided are mammalian host cells that have been transfected with the vectors. In other aspects, guide-retron donor DNA molecules are provided. In some other aspects, methods for genome editing in mammals and the screening of genetic loci are provided. In further aspects, methods and compositions are provided for the prevention or treatment of genetic diseases and for other applications. Kits for genome editing and screening are also provided.

The present disclosure relates to an expression cassette including an rrnA promoter derived from Vibrio natriegens for enhancing the growth rate of Escherichia coli and recombinant Escherichia coli, into which the expression cassette is introduced. More particularly, the present disclosure relates to an expression cassette including the Vibrio natriegens-derived rrnA promoter for enhancing the growth rate of Escherichia coli by introduction thereof into an rrn operon promoter region of Escherichia coli.

Various aspects and embodiments of the present disclosure are directed to methods and compositions for functionalizing endogenous bacteria in vivo. The methods include delivering to endogenous bacterial cells a recombinant bacteriophage or phagemid that is engineered to contain at least one genetic circuit.

The present invention relates generally to synthetic genes for modifying endogenous gene expression in a cell, tissue or organ of a transgenic organism, in particular a transgenic animal or plant. More particularly, the present invention provides novel synthetic genes and genetic constructs which are capable of repressing delaying or otherwise reducing the expression of an endogenous gene or a target gene in an organism when introduced thereto.

The present invention relates generally to a method of modifying gene expression and to synthetic genes for modifying endogenous gene expression in a cell, tissue or organ of a transgenic organism, in particular a transgenic animal or plant. More particularly, the present invention utilizes recombinant DNA technology to post-transcriptionally modify or modulate the expression of a target gene in a cell, tissue organ or whole organism, thereby producing novel phenotypes. Novel synthetic genes and genetic constructs which are capable of repressing delaying or otherwise reducing the expression of an endogenous gene or target gene in an organism when introduced thereto are also provided.

Various aspects and embodiments of the present disclosure are directed to methods and compositions for functionalizing endogenous bacteria in vivo. The methods include delivering to endogenous bacterial cells a recombinant bacteriophage or phagemid that is engineered to contain at least one genetic circuit.

UO.sub.2F.sub.2 biosensors, and related U-sensing and/or F-sensing genetic molecular components, genetic circuits, compositions, methods and systems are described, which in several embodiments can be used to detect and/or neutralize uranium and in particular bioavailable UO.sub.2F.sub.2.

Methods and compositions are provided for durably influencing microbiological ecosystems (microbiomes) in a subject in order to prevent infection and reduce recurrence of infection by microorganisms. In some embodiments, compositions and methods are provided for the creation and use of molecularly-modified bacterial strains with the potential to prevent a variety of microorganism infections.

The invention provides an expression and secretion system, and methods of using the same, for the expression and secretion of one fusion protein in prokaryotic cells and a second fusion protein in eukaryotic cells. Also provided herein are nucleic acid molecules, vectors and host cells comprising such vectors and nucleic acid molecules.

Disclosed is a method that includes: (i) providing a plurality of initial nucleic acid cassettes that include: a) a first coding region encoding a first immunoglobulin variable domain, b) a second coding region encoding a second immunoglobulin variable domain, and c) a ribosomal binding site disposed between the first and second coding regions for translation of the second polypeptide in a first expression system, wherein the first and second coding regions are in the same translational orientation; (ii) modifying each nucleic acid cassette of the plurality in a single reaction mixture so that it is functional in a second expression system, wherein the first and second region remain physically attached during the modifying; (iii) introducing each modified nucleic acid cassette into a mammalian cell to produce a mixture of transfected cells; and (iv) expressing each modified nucleic acid cassette in the transfected cells.