Insights into Transcriptional Regulation of Hepatic Glucose Production.

Maintenance of systemic glucose homeostasis is pivotal in animals because most tissues, especially brain and red blood cells, rely on glucose as the sole energy source. The liver protects the body from hypoglycemia because it possesses two biochemical pathways, namely gluconeogenesis and glycogenolysis which provide glucose during starvation period. Posttranslational regulation by allosteric effectors and/or reversible phosphorylation of the key enzymes involved in these two pathways provide the rapid response for the immediate increase in the enzyme activities to accelerate rates of gluconeogenesis and glycogenolysis, but these mechanisms are insufficient for long-term control. Glucoregulatory hormones can alter the rate of enzyme synthesis at the transcriptional step by modulating the key transcription factors and coactivators, such as CREB/CRTC2, FoxO1, nuclear receptors, C/EBPα, hepatocyte nuclear factors, PGC1α, and CLOCK genes. Precise and well-coordinated regulation of activities of these transcription factors at the right time enables liver to synthesize or suppress glucose production, thus maintaining the proper function of tissues and organs during starvation and feeding cycles. Loss of function mutation or deregulation of these key transcription factors and coactivators can result in the pathophysiological condition, such as type 2 diabetes.

Highly sensitive EGFR mutation detection by specific amplification of mutant alleles.

Mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene predict benefit from tyrosine kinase inhibitors in patients suffering from non-small-cell lung cancer. In this study, we developed a fast, simple, cost-effective and highly sensitive assay for detection of five clinically important EGFR mutations in exon 19 (2235_2249del and 2236_2250del), exon 20 (C2369T) and exon 21 (T2573G and c.2573_2574 TG > GT). We designed EGFR mutation detection assays by combining allele-specific PCR amplification with the detection of SYBR Green I fluorescence, and optimized PCR conditions to specifically amplify mutant alleles. These one-step assays were able to detect the mutations at levels as low as 1.5 mutant copies in a DNA sample. Commercially available probe-based allele-specific PCR exhibited relatively poor performance when detecting very low copies of mutated DNA, especially in exon 19 and 20. Our assays offered dramatically less reagent cost than that of the commercial kit and generated results in less than 90 min after DNA extraction. These protocols can also be applied to conventional thermal cyclers followed by gel electrophoresis detection.