43 results about "Negative selection" patented technology

Strategies, systems, methods, reagents, and kits for phage-assisted continuous evolution are provided herein. These include strategies, systems, methods, reagents, and kits allowing for stringency modulation to evolve weakly active or inactive biomolecule variants, negative selection of undesired properties, and / or positive selection of desired properties.

Engineered transcriptional activator-like effectors (TALEs) are versatile tools for genome manipulation with applications in research and clinical contexts. One current drawback of TALEs is that the 5′ nucleotide of the target is specific for thymine (T). TALE domains with alternative 5′ nucleotide specificities could expand the scope of DNA target sequences that can be bound by TALEs. This disclosure provides methods and strategies for the continuous evolution of proteins comprising DNA-binding domains, e.g., TALE domains. In some aspects, this disclosure provides methods and strategies for evolving such proteins under positive selection for a desired DNA-binding activity and / or under negative selection against one or more undesired (e.g., off-target) DNA-binding activities. Some aspects of this disclosure provide engineered TALE domains and TALEs comprising such engineered domains, e.g., TALE nucleases (TALENs), TALE transcriptional activators, TALE transcriptional repressors, and TALE epigenetic modification enzymes, with altered 5′ nucleotide specificities of target sequences. Engineered TALEs that target ATM with greater specificity are also provided.

The invention provides a genetic intelligent seed breeding and production system for crossbreeding and production of crops and application thereof. The system contains a GAT system vector, and the vector comprises five functional element expression cassettes: a plant male fertility restoration gene element expression cassette used for restoring male fertility of recessive genic male sterility mutants, a plant pollen abortion gene element expression cassette used for removing pollen containing GAT and keeping a heterozygotic state or a hemizygotic state of a GAT maintainer line, a chemical herbicide positive selection expression cassette used for gene transformation and GAT maintainer line impurity removal and purification, a chemical herbicide negative selection expression cassette used for removing herbicide-sensitive GAT maintainer line pollen and seed escape and removing impurities and purifying a GAT sterile line, and a seed screening element expression cassette used for mechanically sorting seeds. The system can be used for crossbreeding and hybrid seed production of plant recessive genic male sterility materials, so that new varieties of plants with high quality, high yield, wide applicability and high resistance and seeds of the plants are obtained.

The present invention provides methods, compositions and kits for the generation of next generation sequencing (NGS) libraries in which non-desired nucleic acid sequences have been depleted or substantially reduced. The methods, compositions and kits provided herein are useful, for example, for the production of libraries from total RNA with reduced ribosomal RNA and for the reduction of common mRNA species in expression profiling from mixed samples where the mRNAs of interest are present at low levels. The methods of the invention can be employed for the elimination of non-desired nucleic acid sequences in a sequence-specific manner, and consequently, for the enrichment of nucleic acid sequences of interest in a nucleic acid library.

A process for constructing a catalogued nucleic acid library in which the proportional representation of the constituents is adjusted to advantage through the use of disclosed technologies for positive and negative selection. The resultant benefit is that significantly fewer library constituents will need to be screened in order to identify a potentially desired constituent. Moreover, library constituents that previously would have been essentially “lost” are now recoverable. Preferred embodiments of this invention include the cataloguing, normalization, and enrichment of library constituents. By way of example, but not limitation, this technology is serviceable for constructing a library that contains an adequate representation of desirable constituents that (1) are initially found in low-copy numbers within a sample source or (2) originate from an organism that is problematic to culture. Applicable uses of this invention include any library-screening endeavor previously hindered by logistical impediments.By expanding previous logistical frontiers this invention allows for a novel generation of previously unattainable molecules—particularly molecules that are “unclonable” from conventional, unadjusted libraries—to now be detected, cloned, manipulated, expressed, studied, and used. By disclosing the construction and screening of high yielding nucleic acid libraries from mixed and uncultivated organisms, the instant technology eclipses former boundaries in the area of biological discovery and enables the full breadth of biological diversity to be accessed in the search for previously undiscovered genes and gene products. The benefits of the present invention are seen to extend to areas of diagnosis, medicine, agriculture, manufacturing, and academia.

The invention provides a gene editing system based on a CRISPR-Cas9 technology and application of the gene editing system. Based on an endogenous U6 promoter dependent-form vector system, a negative selection marker is added into a Cas9 expression box of an expression vector, an anti-drug selection marker on a rescue vector containing a homologous arm is transferred onto the expression vector, thus the base size of the rescue vector is decreased, and the capacity of the rescue vector is increased; and an exogenous gene segment lengthening out to 6.3 kb can be input in human plasmodium in a mediated mode, obtained recombinant plasmodium does not contain the anti-drug selection marker and Cas9 protein expression plasmid residue, continuous gene editing can be conducted through the same drugselection marker, and the gene editing system is stable in performance, efficient, concise, and powerful in function, and has wide application prospects and huge market value.

The invention describes a highly improved, reproducible and a consistent method of transformation and regeneration that results in obtaining 12-15% transgenic plants. The present invention relates to a method of selecting genetically transformed Sunflower explants based on their ability to utilize Xylose as a sole carbohydrate source. Further disclosed is the nucleic acid sequence of the Xylose Isomerase gene, vector construction for incorporation of the selection marker gene and the process of Agrobacterium Mediated Transformation of target host plant with the vector comprising the gene encoding the enzyme Xylose isomerase under the functional combination of the heterologous regulatory sequences. Also disclosed is the method of selecting the putative transformants post transformation with the said vector that possess a metabolic advantage of utilizing Xylose as a sole carbon source.; Increased efficiency of regeneration, better growth and survival has been observed on subjection to the described method of positive selection. The subject invention alleviates the disadvantages of negative selection methods such as the undesired elimination of the transformed cells and the potential environmental harm caused due to the dispersal of the antibiotic and the herbicide resistant genes.

The invention relates to a method for the simultaneous integration of two or more copies of a polynucleotide of interest into the chromosome of a fungal host cell comprising at least two pairs of recognition sequences of a site-specific recombinase, each pair flanking a resident negative selection marker; transformation of the cell with a construct carrying a gene of interest also flanked by the recognition sequences to ensure double-crossover events after transient expression of the recombinase, followed by selection for excision of all negative selection markers from the cell.

An in vivo method for the construction of randomized gene libraries and / or domain replacement in gene libraries by homologous recombination using a Kluyveromyces lactis killer toxin, in particular the (γ-subunit of the K. lactis killer toxin, as negative selection marker is described. The use of the (γ-subunit of K. lactis as negative selectable marker increases the percentage of randomized clones.

There is provided herein a method for identifying and / or recovering at least one genetically encoded affinity reagent specific for a target molecule by screening using molecular display in conjunction with the sequencing of positive and negative selection pools from the screen.

Synthetic auxotrophs with one or more ligand-dependent essential gene functions and methods of production that can be used for biosafety. The ligand-dependent function of an essential gene product can be produced by a series of mutations in the ORF of an essential gene; N, C, or insertional fusions of ligand-binding domains with essential genes or an engineered ligand-dependent intein splicing to alter essential gene function. A positive and / or negative selection can be used to identify auxotrophs from created mutant libraries. The positive selection is performed by growing a mutant library in conditions where growth or viability depends on the function of mutagenized essential genes. The negative selection eliminates constitutively growing cells that do not require a ligand for growth by growing the library in the absence of complementing ligand and in conditions where growing cells are eliminated. Desirable phenotypes are collected after the selections.

Methods of assessing circulating tumor cells (CTCs) and methods of using the data obtained from assessing CTCs are provided. The methods employ negative selection and 3D cell culture techniques to isolate and culture CTCs. Those CTCs then can be used in different bioassays or evaluations, such as to determine tumor morphology, monitor tumor status, predict prognosis, provide treatment suggestion,and assess treatment effectiveness.