Notes: The authors used a biochemical assay using Xenopus egg extracts to monitor degradation levels of two Wnt pathway components, Axin and ß-catenin, and identify modulators of the Wnt pathway. ß-catenin and Axin were expressed in vitro as firefly and Renilla luciferase fusion proteins, respectively, using the TNT^® SP6 High-Yield Protein Expression System and shown to behave in Xenopus extracts in a similar way to wildtype proteins, which were expressed as radiolabled proteins in rabbit reticulocyte lysate. Degradation of labeled proteins was monitored by SDS polyacrylamide gel electrophoresis and autoradiography, and degradation of luciferase fusion proteins was examined using the Dual-Glo^® Luciferase Assay. Using the Xenopus extract-based assay, the authors screened chemical libraries to identify two modulators of the Wnt pathway, then confirmed this inhibition in HEK 293 cells by demonstrating a decrease in ß-catenin expression with increasing concentrations of the inhibitors. This decrease in ß-catenin-Fluc levels was measured using the Steady-Glo™ Luciferase Assay, and luciferase activity was normalized to cell viability, as determined using the CellTiter-Glo^® Assay. (4181)

Notes: These authors used the Flexi^® Vector System to prepare ORF clones encoding 1929 human genes and to transfer a subset of these clones to various expression vectors for further analysis. They created HaloTag^® fusion proteins and examined expression of these proteins in vitro and in COS7 and HEK293 cells. They also performed comparisons between the Flexi^® System and Gateway^® cloning system, specifically examining the effects of flanking sequences on protein expression in in vitro translation systems and confirming that the cellular localization of the HaloTag^® fusion proteins was consistent with results obtained using GFP-fusions. (3800)

Notes: These authors tested the effect of different washing, drying and storage conditions on the stability of various protein:protein interaction arrays. They tested five different interacting protein pairs and three enzymes, monitoring stability and activity under various processing conditions. They found that addition of 5% glycerol to the wash buffer helped retain enzyme activity during washing and drying. There was significant loss of enzyme activity when slides were stored dry at 4^oC but slides stored at -20^oC in 50% glycerol retained enzyme activity. HaloTag-fused enzymes in cell-free extracts could undergo multiple freeze-thaw cycles without significant effect on enzyme activity, indicating that such extracts could be frozen at -70^oC and used to print small batches of arrays at various intervals over a period of weeks. (3890)