• Floral morphology of smd3 knock-out mutants
  • Knock-out mutants from an En-1 mutagenized …
  • Knock out mutants essays

subtilis mutants knock out and knockout to produce less odor than the wild type.

Knock-out mutants from an En-1 mutagenized Arabidopsis thaliana ..

Yeast Knockout Collection | Dharmacon

Knock-out mutations of Arabidopsis SmD3 - DeepDyve
As a second level of comparison, we identified differences in reaction and gene content which give rise to different functional predictions of single and double gene knockout mutants using Comparison of Networks by Gene Alignment (CONGA).

The leucine dehydrogenase knock out mutants …

Knock-out mutations are available in most wheat genes providing an invaluable resource for characterising gene function.
Background: Klebsiella pneumoniae is a leading cause of hospital-acquired urinary tract infections and pneumonia worldwide, and is responsible for many cases of pyogenic liver abscess among diabetic patients in Asia. A defining characteristic of this pathogen is the presence of a thick, exterior capsule that has been reported to play a role in biofilm formation and to protect the organism from threats such antibiotics and host immune challenge. Findings. We constructed two knockout mutants of K. pneumoniae to investigate how perturbations to capsule biosynthesis alter the cellular phenotype. In the first mutant, we deleted the entire gene cluster responsible for biosynthesis of the extracellular polysaccharide capsule. In the second mutant, we deleted the capsule export subsystem within this cluster. We find that both knockout mutants have lower amounts of capsule but produce greater amounts of biofilm. Moreover, one of the two mutants abolishes fimbriae expression as well. Conclusions: These results are expected to provide insight into the interaction between capsule biosynthesis, biofilm formation, and fimbriae expression in this organism.

 

We constructed two knockout mutants of K

The knockout strains were validated with the PCR reaction.Growth curve:The growth kinetics of the wild type and the mutant strains of
A gene-targeting vector (left panel) is constructed to delete a specific exon of a gene in embryonic stem cells. Several kilobases of DNA on either side of the target gene are cloned around a drug-selection marker. After the cloned DNA (targeting vector) is introduced into the stem cells, positive and negative drug selection occurs in culture. The left panel shows a targeting vector that was constructed with sequences flanking the positive drug-selection gene. Cre recombinase can delete the DNA sequence between the sites, thereby deleting a specific gene in the embryonic stem cells. Knock-in mice (right panel) are generated by replacement of an endogenous exon with one harboring a mutation of interest. The gene-targeting strategy is similar to that used for knockout mice, except that a replacement exon (indicated by a star) is exchanged with the endogenous exon. Cre– strategies can delete most traces of the targeting vector. Once the desired stem-cell clone is selected, it is injected into a blastocyst, which is implanted into the uterus of a foster mother. If the gene-targeted stem cells contribute to germ cells in the chimeric mice, subsequent offspring will harbor the gene-targeted mutation (germ-line transmission).


A gene-targeting vector (left panel) is constructed to delete a specific exon of a gene in embryonic stem cells. Several kilobases of DNA on either side of the target gene are cloned around a drug-selection marker. After the cloned DNA (targeting vector) is introduced into the stem cells, positive and negative drug selection occurs in culture. The left panel shows a targeting vector that was constructed with sequences flanking the positive drug-selection gene. Cre recombinase can delete the DNA sequence between the sites, thereby deleting a specific gene in the embryonic stem cells. Knock-in mice (right panel) are generated by replacement of an endogenous exon with one harboring a mutation of interest. The gene-targeting strategy is similar to that used for knockout mice, except that a replacement exon (indicated by a star) is exchanged with the endogenous exon. Cre– strategies can delete most traces of the targeting vector. Once the desired stem-cell clone is selected, it is injected into a blastocyst, which is implanted into the uterus of a foster mother. If the gene-targeted stem cells contribute to germ cells in the chimeric mice, subsequent offspring will harbor the gene-targeted mutation (germ-line transmission).


(unmarked) knock-out mutants obtained after counterselection of a ..

Initially, knockout mice were produced by replacing or disrupting the coding exons of a gene with a drug-selection marker. Such mice could be used to study only the effects of the loss of a gene, not a specific mutation. For the latter purpose, a “knock-in” method was developed, in which a mutated DNA sequence is exchanged for the endogenous sequence without any other disruption of the gene. Some knock-in strategies rely on the use of gene vectors with flanking sequences, termed , that on exposure to an enzyme called Cre recombinase undergo reciprocal recombination, leading to the deletion of the intervening DNA. With this method, it is possible to replace a gene sequence with a sequence of the investigator's choice and to delete unnecessary sequences (see ). The gene for Cre recombinase has been knocked into targeted loci in a way that brings its expression under the direction of the endogenous gene promoter, thus allowing tissue-specific or temporal-specific expression of the Cre enzyme and hence recombination of sites that flank the gene of interest. Applications of this method are numerous, and some are already clinically useful. For example, knock-in of segments of the human immunoglobulin gene into the mouse genome enables mice to produce therapeutically useful humanized antibodies. As gene-targeting technologies and strategies evolve, it may become possible to create mouse models of polygenic human diseases such as diabetes and hypertension.

Double knock-out mutants of Arabidopsis thaliana …

Evans, Smithies, and Capecchi quickly sought to repair mutated genes in embryonic stem cells. Smithies and Capecchi focused on correcting defects of the gene in such cells by identifying and selecting cells that had undergone homologous recombination, thereby eliminating the mutant gene. This work, in which gene targeting was accomplished by homologous recombination, led to the development of a general method by which a specific gene in an embryonic stem cell can be inactivated; the genetically altered cell, after implantation into a surrogate mother, ultimately gives rise to a strain of mice that is homozygous for the inert gene — the “knockout mouse.” The technique has been used to generate thousands of different kinds of knockout mice with features of particular human diseases. More remarkable is the transformation of our understanding of gene function: rather than relying on spontaneous mutations to deduce gene function, we can now use experimentally targeted mutations to test a gene's functional role prospectively.