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Targeted Gene Disruption (targeted + gene_disruption)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Generation of Novel Landomycins M and O through Targeted Gene Disruption

CHEMBIOCHEM, Issue 4 2005
Andriy Luzhetskyy Dr.
Abstract Two genes from Streptomyces cyanogenous S136 that encode the reductase LanZ4 and the hydroxylase LanZ5, which are involved in landomycin A biosynthesis, were characterized by targeted gene inactivation. Analyses of the corresponding mutants as well as complementation experiments have allowed us to show that LanZ4 and LanZ5 are responsible for the unique C-11-hydroxylation that occurs during landomycin biosynthesis. Compounds accumulated by the lanZ4/Z5 mutants are the previously described landomycin F and the new landomycins M and O. [source]

Manipulating gene activity in Wnt1-expressing precursors of neural epithelial and neural crest cells

DEVELOPMENTAL DYNAMICS, Issue 1 2010
Wei Hsu
Abstract Targeted gene disruption or expression often encounters lethality. Conditional approaches, permitting manipulation at desired stages, are required to overcome this problem in order to analyze gene function in later developmental processes. Wnt1 has been shown to be expressed in neural crest precursors at the dorsal midline region. However, its expression was not detected in emigrated neural crest cells, the descendants of Wnt1-expressing precursors. We have developed mouse transgenic systems to manipulate gene activity in the Wnt1-expressing precursors and their derivatives by integrating the tetracycline-dependent activation and Cre-mediated recombination methods. A new Wnt1-rtTA strain, carrying rtTA under control of Wnt1 regulatory elements, has been created for gene manipulation in a spatiotemporal-specific fashion. Together with our previously developed Wnt1-Cre;R26STOPrtTA model, these systems permit conditional gene expression and ablation in pre-migratory and/or post-migratory neural crest cells. This study demonstrated the versatility of our mouse models to achieve gene manipulation in early neural development. Developmental Dynamics 239:338,345, 2010. © 2009 Wiley-Liss, Inc. [source]

Mouse models in non-alcoholic fatty liver disease and steatohepatitis research

INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 1 2006
Quentin M. Anstee
Summary Non-alcoholic fatty liver disease (NAFLD) represents a histological spectrum of liver disease associated with obesity, diabetes and insulin resistance that extends from isolated steatosis to steatohepatitis and cirrhosis. As well as being a potential cause of progressive liver disease in its own right, steatosis has been shown to be an important cofactor in the pathogenesis of many other liver diseases. Animal models of NAFLD may be divided into two broad categories: those caused by genetic mutation and those with an acquired phenotype produced by dietary or pharmacological manipulation. The literature contains numerous different mouse models that exhibit histological evidence of hepatic steatosis or, more variably, steatohepatitis; however, few replicate the entire human phenotype. The genetic leptin-deficient (ob/ob) or leptin-resistant (db/db) mouse and the dietary methionine/choline-deficient model are used in the majority of published research. More recently, targeted gene disruption and the use of supra-nutritional diets to induce NAFLD have gained greater prominence as researchers have attempted to bridge the phenotype gap between the available models and the human disease. Using the physiological processes that underlie the pathogenesis and progression of NAFLD as a framework, we review the literature describing currently available mouse models of NAFLD, highlight the strengths and weaknesses of established models and describe the key findings that have furthered the understanding of disease pathogenesis. [source]

Zeocin resistance as a dominant selective marker for transformation and targeted gene deletions in Candida glabrata

MYCOSES, Issue 6 2006
Alex J. Alderton
Summary Many of the genetic tools used to generate gene knockouts in Candida glabrata exploit auxotrophic markers but this is not suitable for use with clinical strains. Antibiotic resistance markers, however, allow one to target genes to be deleted without any prior genetic manipulation of clinical isolates. Such antibiotic selection markers have been widely reported for the manipulation of Saccharomyces cerevisiae. However, very few antibiotic resistance markers have been shown to be useful in C. glabrata. Here, we report the use of Zeocin resistance (ZeoR), encoded by the ble gene from Streptoalloteichus hindustanus, as a new positive selection marker for the genetic manipulation of C. glabrata including clinical strains that we show are significantly more sensitive to Zeocin than to G418. The potential of the ZeoR marker for targeted gene disruption in C. glabrata was confirmed by constructing deletions of the ADE2 in both a laboratory and a clinical strain of C. glabrata, using both short (90 bp) and long (400 bp) homology cassettes. [source]