206 results about "Site-specific recombination" patented technology

DNA constructs comprise a first exon sequence of nucleotides encoding a first peptide or polypeptide, a second exon sequence of nucleotides encoding a second peptide or polypeptide and a third sequence of nucleotides between the first and second sequences encoding a heterologous intron, for example that of Tetrahymena thermophila nuclear pre-rRNA, between RNA splice sites and a site-specific recombination sequence, such as loxP, within the intron, the exons together encoding a product peptide or polypeptide. Such constructs are of use in methods of production of peptides or polypeptides, transcription leading to splicing out of the intron enabling translation of a single chain product peptide or polypeptide. Isolated nucleic acid constructs consisting essentially of a sequence of nucleotides encoding a self-splicing intron with a site-specific recombination sequence within the intron, for use in creation of constructs for expression of peptides or polypeptides, are also provided.

Some aspects of this disclosure provide compositions, methods, and kits for improving the specificity of RNA-programmable endonucleases, such as Cas9. Also provided are variants of Cas9, e.g., Cas9 dimers and fusion proteins, engineered to have improved specificity for cleaving nucleic acid targets. Also provided are compositions, methods, and kits for site-specific recombination, using Cas9 fusion proteins (e.g., nuclease-inactivated Cas9 fused to a recombinase catalytic domain). Such Cas9 variants are useful in clinical and research settings involving site-specific modification of DNA, for example, genomic modifications.

An embodiment of a method for obtaining a DNA construct comprising two end regions of a target nucleic acid in an in vitro reaction is described that comprises the steps of: fragmenting a large nucleic acid molecule to produce a target nucleic acid molecule; ligating a recombination adaptor element to each end of the target nucleic acid molecule to produce an adapted target nucleic acid molecule; exposing the adapted target nucleic acid to a site specific recombinase to produce a circular nucleic acid product and a linear nucleic acid product from the adapted target nucleic acid, wherein the circular nucleic acid product comprises the target nucleic acid molecule; and fragmenting the circular nucleic acid product to produce a template nucleic acid molecule comprising a sequence region from each end of the target nucleic acid molecule.

The invention provides a bacterium containing a polynucleotide comprising a nucleic acid encoding a heterologous antigen, as well as fusion protein partners. Also provided are vectors for mediating site-specific recombination and vectors comprising removable antibiotic resistance genes.

The subject invention pertains to materials and methods for preparing multi-potential stem cells having a pre-selected expression of MHC antigens. Stem cells of the subject invention can be used to generate histocompatible tissues/organs for transplantation. The process of the subject invention comprises the use of targeting vectors capable of gene knockout, insertion of site-specific recombination cassettes, and the replacement of histocompatibility alleles in the stem cell. Novel knockout vectors are used to delete designated regions of one chromosome. Recombination cassette vectors are then used to delete the same region on the second chromosome and deposit a site-specific recombination cassette which can be utilized by replacement vectors for inserting the new MHC genes on the chromosome of the engineered cell. The subject invention also pertains to cells, tissues, and transgenic mammal prepared using the methods and materials of the invention.

Site-specific recombinase based methods for making a recombinant adenoviral genome, as well as kits for practicing the same and the recombinant adenovirus vectors produced thereby, are provided. In the subject methods, the subject genomes are prepared from donor and acceptor vectors that each include at least one site recombinase recognition site, where in certain preferred embodiments, one of the donor and acceptor vectors includes a single recombinase recognition site while the other includes two recombinase recognition sites. The acceptor vector includes an adenoviral genome having an E region deletion. The donor vector includes an insertion nucleic acid. In the subject methods, the donor and acceptor vectors are combined in the presence of a recombinase to produce an adenoviral genome that includes the insertion nucleic acid. The subject adenoviral genomes find use in a variety of applications, including as vectors for use in a variety of applications.

The subject invention provides a unidirectional site-specific integration system for integrating a nucleic acid into the genome of a target cell. The provided system includes a site-specific integrating expression cassette (INTEC) vector, consisting of (a) a polynucleotide of interest operably linked to a promoter, (b) a single recombination site, and (c) a hybrid recombination site. In using the subject systems for site-specific integration, the INTEC vector and integrase are introduced into the target cell and the cell is maintained under conditions sufficient to provide for site-specific integration of the nucleic acid into the target cell genome via a recombination event mediated by the site-specific recombinase. Also provided are kits that include the subject systems. The subjects systems, methods and kits find use in a variety of different applications, several representative ones of which are described in detail as well.

Methods for inserting a polynucleotide sequence into the genome of a human cell are provided. The present methods result in insertion of a polynucleotide sequence of interest into the H11 locus in the genome of a human cell. Also provided are nucleic acids that include sequences for integrating a polynucleotide sequence of interest into the H11 locus in the genome of a human cell. A transgenic human cell including site specific recombination sites at the H11 locus is also disclosed.

Compositions, kits, and methods are provided for use in a recombinational cloning or subcloning methods for constructing expression vectors which comprise: ligating a library of double-stranded linear donor DNAs, where each member of the library includes a donor DNA sequence, with a double-stranded linear driver DNA which includes a promoter sequence and a donor recombination site to form a single circular donor DNA, the single circular donor DNA not including an origin of replication, where the donor DNA sequence is under the transcriptional control of the promoter; and contacting the circular donor DNA and a circular acceptor acceptor vector in the presence of a recombinase to form a single fused circular vector, the circular acceptor vector comprising an origin of replication and an acceptor recombination site capable of recombining with the circular donor DNA.

The present invention is a cell-free subcloning system utilizing three elements: (1) a donor vector that contains a nucleic acid sequence to be transferred to another vector flanked by a site-specific recombination sequence and one or more optional additional nucleic acid sequences, (2) an acceptor vector that contains a site-specific recombination sequence and one or more optional additional nucleic acid sequences, and (3) a site-specific recombinase that recognizes the site-specific recombination sequences in the donor and acceptor vectors so as to transfer the transfer sequence from the donor to the acceptor vector upon contact of the three elements of the system. Also disclosed are rapid subcloning methods employing the vectors and enzymes disclosed herein and kits for use in such methods.

The present invention provides methods for the conditional or regulated expression of a site-specific recombinase using split intein-mediated protein splicing. This enhances the temporal and tissue-specificity of trait gene expression and allows for fine tuning of expression specificity.

The present invention is transgenic chickens obtained from long-term cultures of avian PGCs and techniques to produce and transgenic birds derived from prolonged PGC cultures. In some embodiments, these PGCs can be transfected with genetic constructs to modify the DNA of the PGC, specifically to introduce a transgene encoding an exogenous protein. When combined with a host avian embryo by known procedures, those modified PGCs are transmitted through the germline to yield transgenic offspring. This invention includes compositions comprising long-term cultures of PGCs and offspring derived from them that are genetically modified. The genetic modifications introduced into PGCs to achieve the gene inactivation may also include, but are not restricted to, random integrations of transgenes into the genome, transgenes inserted into the promoter region of genes, transgenes inserted into repetitive elements in the genome, site specific changes to the genome that are introduced using integrase, site specific changes to the genome introduced by homologous recombination, and conditional mutations introduced into the genome by excising DNA that is flanked by lox sites or other sequences that are substrates for site specific recombination.

The present invention provides in vivo systems in which activity of a biological cleavage enzyme, such as a site-specific recombinase, a homing endonuclease, or an intein, is linked to cell viability and therefore can be selected. The invention further provides methods of making cells in which the activity of a biological cleavage enzyme is linked to viability, as well as methods of identifying new biological cleavage enzymes, including enzymes having altered site specificity, using such cells.

The invention relates to methods and compositions for site-specific recombinase-mediated mobilization of viral replicons and associated DNAs of interest from T-DNA. The methods of the invention comprise Agrobacterium-mediated transfer of T-DNA to a plant cell, wherein the T-DNA contains a viral replicon flanked by directly repeated target sites for a site-specific recombinase and optionally a DNA of interest linked to the viral replicon. The DNA of interest may also contain a non-identical target site for the recombinase. An expression cassette for the site-specific recombinase is present on the T-DNA or the plant genome, or is transiently introduced into the plant cell. Expression of the site-specific recombinase in the plant cell results in excision of the viral replicon and the associated DNA of interest. The viral replicon and DNA of interest are then replicated to high copy number in the host plant cell. The compositions of the invention comprise nucleic acids, such as T-DNAs containing a viral DNA flanked by directly repeated target sites for a site-specific recombinase. The nucleic acids of the invention may additionally contain expression cassettes encoding the cognate site-specific recombinase for the target sites flanking the viral genome. The compositions of the invention further comprise Agrobacterium containing the nucleic acids of the invention. The compositions and methods of the invention have use in increasing the efficiency of agroinfection, providing high copy numbers of a DNA of interest for transient expression or for integration into a plant chromosome, and in simplifying the construction and stable maintenance of vectors for agroinfection and transformation.

This invention relates to constructs for the conditional or regulated expression of transgenes in plants using site-specific recombinase systems. The constructs comprise a variety of constitutive, inducible, tissue specific or developmental stage-specific promoters operably linked to either a transgene or the elements of one or more site-specific recombinase system. By matching promoters, responsive to various inducers, plant tissues or plant developmental states with the recombinase systems, stop fragments and transgenes, virtually any trait may be expressed at any plant development stage or in any plant generation.

The invention provides a bacterium containing a polynucleotide comprising a nucleic acid encoding a heterologous antigen, as well as fusion protein partners. Also provided are vectors for mediating site-specific recombination and vectors comprising removable antibiotic resistance genes.

The invention discloses a method for constructing a recombinant expression vector simultaneously expressing a plurality of genes. An MISSA system consists of a strain and a vector, wherein the strain comprises a donor strain and an acceptor strain; the vector comprises a donor vector and an acceptor vector; replication initiation protein carried by a chromosome of the donor strain is responsible for replicating and amplifying a suicidal donor vector, and the carried conjugal transfer protein Tra is responsible for conjugal transfer of the donor vector; the acceptor strain can induce and express two sets of locus specific recombinant proteins, namely Cre recombinant enzyme and lambda phage locus specific recombinant proteins; when the donor strain is mixed with the acceptor strain, the donor strain and the acceptor strain are conjugated, and the donor strain is transferred into the acceptor vector because the donor vector in the donor strain carries an oric element; and the donor vector and the acceptor vector undergo recombination reaction in the acceptor strain under the action of the two sets of locus specific recombinant proteins, so that a target gene carried by the donor vector is assembled onto the acceptor vector. The process is repeated, so a plurality of target genes can be assembled onto the acceptor vector according to the preset direction and order.