Mutations in the KCNT1 (Slack, K1.1) sodium-activated potassium channel produce severe epileptic encephalopathies. Expression in heterologous systems has shown that the disease-causing mutations give rise to channels that have increased current amplitude.
View Article and Find Full Text PDFGene switches have wide utility in synthetic biology, gene therapy, and developmental biology, and multiple orthogonal gene switches are needed to construct advanced circuitry or to control complex phenotypes. Endogenous vascular endothelial growth factor (VEGF-A) is crucial to angiogenesis, and it has been shown that multiple alternately spliced VEGF-A isoforms are necessary for proper blood vessel formation. Such a necessity limits the utility of direct transgene delivery, which can provide only one splice variant.
View Article and Find Full Text PDFBiotechnol Bioeng
December 2011
Estrogenic compounds are an important class of hormonal substances that can be found as environmental contaminants, with sources including pharmaceuticals, human and animal waste, the chemical industry, and microbial metabolism. Here we report the creation of a biosensor useful for monitoring such compounds, based on complementation of fluorescent protein fragments. A series of sensors were made consisting of fragments of a split mVenus fluorescent protein fused at several different N-terminal and C-terminal positions flanking the ligand binding domain of the estrogen receptor alpha.
View Article and Find Full Text PDFBiotechnol Bioeng
February 2008
Phosphite dehydrogenase represents a new enzymatic system for regenerating reduced nicotinamide cofactors for industrial biocatalysis. We previously engineered a variant of phosphite dehydrogenase with relaxed cofactor specificity and significantly increased activity and stability. Here we performed one round of random mutagenesis followed by comprehensive saturation mutagenesis to further improve the enzyme thermostability while maintaining its activity.
View Article and Find Full Text PDFToxicol Appl Pharmacol
July 2002
Long-term treatment of rodents with peroxisome proliferator chemicals, a group of structurally diverse nongenotoxic carcinogens, leads to liver cancer in a process dependent on the nuclear receptor peroxisome proliferator-activated receptor-alpha (PPARalpha). Previous in vitro studies have shown that growth hormone (GH) can inhibit PPARalpha-dependent gene expression by down-regulation of PPARalpha expression and by a novel inhibitory cross-talk involving the GH-activated transcription factor STAT5b. Presently, we evaluate the role of STAT5b in mediating these inhibitory actions of GH on PPAR function using a STATb-deficient mouse model.
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