Notes: The authors of this study investigated the role of the genes CLV1 and CLV3 stem cell renewal and differentiation in self-renewing shoot apical meristem (SAM) in Arabidopsis. CLV1 encodes a receptor kinase that is a negative regulator of cell growth, and therefore cannot be overexpressed in plant cells. CLV3, which encodes a protein that is processed to a 12-amino acid peptide, is believed to be a ligand for CLV1. In this study, the authors made a construct in which the CLV1 kinase domain was replaced with the HaloTag™ protein and expressed the fusion protein in tobacco BY-2 cells. The fusion protein was detected using the HaloTag™ TMR ligand. They next incubated membrane extracts from wildtype and transgenic BY-2 cells (expressing the HaloTag™-CLV1 fusion) with tritium-labeled CLV3. The transgenic cells showed significantly higher CLV3 binding than wildtype, and the authors show that CLV3 specifically labels a 130-kd band that corresponds to the HaloTag™-CLV1 fusion protein, indicating that CLV3 binds the ectodomain of CLV1. (3763)

Notes: The authors examined the different ATP sensitivities of inositol (1,4,5)-triphosphate receptor (InsP₃R) isoforms InsP₃R1, InsP₃R2 and InsP₃R3. To compare the ATP-binding properties of InsP₃R2 and InsP₃R3, nucleotide sequences encompassing the ATP-binding domains were amplified by PCR and cloned into the pFN2A (GST) Flexi^® Vector. The ATP-binding sites were expressed as glutathione-S-transferase (GST) fusion proteins in BL21(DE3)pLysS cells. Fusion proteins were purified, and the GST tag removed by cleavage with tobacco etch virus (TEV) protease. Purified proteins were then used in a fluorescent ATP-binding assay. (3901)

Notes: The authors identified the N-terminal Src homology 3 (SH3) domain-binding motif of Crk and CrkL as the preferred binding partner of nonstructural protein 1 (NS1), an important virulence factor of the influenza A virus. Interaction of NS1 with Crk, CrkL and other SH3 domain-containing proteins p85, p85β and Eps8L1 was investigated by protein pull-down assays. Expression constructs for biotinylated Crk, CrkL, p85, p85β and Eps8L1 were created by amplifying the 123 amino acid biotin acceptor domain from Propionibacterium shermanii from the PinPoint Xa-T Vector and inserting it upstream of the protein-coding sequences in a pGEX vector derivative. These constructs and a construct encoding Myc-tagged NS1 were transfecting into 293FT cells, and the biotinylated proteins were immobilized from the cell lysate using TetraLink™ Tetrameric Avidin Resin. Any Myc-NS1 that bound to the immobilized protein was detected using Western Blot analysis and an anti-Myc antibody. The authors also investigated the ability of wildtype NS1 or NS1 mutants to inhibit interferon-induced gene expression. A reporter plasmid was created by cloning an interferon-stimulated response element upstream of a minimal thymidine kinase promoter driving firefly luciferase expression. A vector containing Renilla luciferase was used as a control to normalize transfection efficiency. Huh-7 cells were cotransfected with the firefly and Renilla luciferase reporter constructs (0.2µg and 5ng, respectively), treated with interferon-β and lysed using the Passive Lysis Buffer. Firefly and Renilla luciferase activities were measured using the Dual Luciferase Reporter Assay System. (3803)

Notes: The authors of this review article highlight the use of bioluminescence as a readout for high-throughput ADME/Tox assays. They discuss three strategies for designing bioluminescent assays, using either luciferase, ATP or luciferin substrates as the limiting reagents for a luciferase-catalyzed reaction. Reporter gene assays limit the production of luciferase by tying it to a promoter or DNA regulatory region of interest. Such assays can be used to study genes that are regulated by drugs and other xenobiotics. Bioluminescent assays in which ATP is the limiting reagent of the luciferase reaction can be designed to monitor cell viability or the activity kinases. Bioluminescent assays in which the substrate is limiting can be designed so that the activity of a particular enzyme results in the production of a luciferin substrate that can, in turn, be acted upon by luciferase. (3926)

Notes: The authors of this study investigated the role of Lyn, a Src-family tyrosine kinase, in regulating the formation of the phagosome in alveolar macrophages in response to Psuedomonas aeruginosa (PA) infection. The Kinase-Glo^® Assay was used to assess Lyn activity, using acid-denatured enolase as the substrate. The authors found that Lyn kinase activity was increased following infection with PA. (3929)

Notes: HEK-293 were transiently transfected with adenovirus 5 DNA using FuGENE® 6 Reagent. Cells were seeded at 3 × 10⁶ cells/75 cm² and grown to 60% cell confluency prior to transfection. Cell transfections were 60–70% efficient. (4266)

Notes: The authors of this paper compared time-resolved, fluorescence energy transfer and ATP-based luminescent assays in ultrahigh-throughput screens (1536-well) for Rho-associated kinase II inhibitors. They found that both technologies are suitable for such a screen and perform similarly; however, they note that the ATP-based luminescent kinase assay provides an economical advantage. (3932)

Notes: HepG2 cells in a T-25 culture flask (3 million cells at 70ndash;80% confluency) were transfected with CYP3A4 reporter plasmid (a pGL3 reporter construct) and a CMV-Renilla control plasmid (a total of 2.5µg of plasmid mix was used) using FuGENE® 6 Reagent for transient transfection assays. Reporter activities were measured using the Dual-Glo® Luciferase Assay System. (4268)

Notes: To examine the role of cyclin-dependent kinase (cdk)-3 expression in cancer cell lines, potential targets of cdk3 phosphorylation were examined. The CheckMate™ Mammalian Two-Hybrid System was used to test for transcription factor binding partners of cdk in HEK293 cells. Cell proliferation of T96G cells stably transfected with either cdk3 or vector was assessed using the CellTiter 96® AQueous One Solution Cell Proliferation Assay. (3983)

Notes: The authors describe the developmental validation of the Plexor^® HY System, a quantitative PCR assay that simultaneously quantifies total human and male DNA. Validation studies examined: (1) human specificity, (2) sensitivity, (3) quantitation of degraded DNA, (4) impact of inhibitors, (5) male/female mixture and Y-assay male specificity, (6) reproducibility and concordance and (7) population studies. (3969)

Notes: Regulation of genes targeted by the ligand-activated aryl hydrocarbon receptor (AhR) has been shown to be controlled by calcium (Ca(2+)) changes induced by AhR agonists such as the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). This study investigated this link. As part of the study, MCF-7 cells were transfected with various pGL3 firefly luciferase reporter constructs and the control pRL-TK Vector expressing Renilla luciferase. Transfection conditions were as follows: MCF-7 cells were cultured in 24-well plates and transfection was performed using FuGENE® 6 transfection reagentwith a FuGENE:DNA ration of 3:1. Firefly and Renilla luciferase activities were measured using the Dual-Luciferase® Reporter Assay System. (4362)

Notes: The authors of this study created a cDNA library representative of the extracellular proteome (secreted proteins and the extracellular domains of transmembrane proteins). Each cDNA was individually transfected into 293T cells. Medium from the cDNA of each transfection was used in a suite of cell-based assays. The CellTiter-Glo^® Assay was used to screen for secreted factors from the cell lines expressing the cDNA that affected viability of twelve cell lines: human primary B cells, human primary T cells, human primary NK cells, human primary monocytes, A549 cells, Colo205 cells, U-118 cells, MDA-MB231 cells, PC3 cells, PANC1 cells, human primary skeletal muscle progenitor cells, and rat primary oligodendrocyte precursor cells. (3935)

Notes: The authors performed protein pull-down assays to characterize the interaction of ORAI1 and STIM1, two protein components of the calcium-release calcium current. His₆-STIM1 C terminus and ORAI1 were synthesized using the TNT® Coupled Reticulocyte Lysate System in the presence of ³⁵S, and His₆-STIM1 C terminus was immobilized using MagZ™ Binding Particles. An aliquot of the TNT® reaction expressing ORAI1 was added to the particles, and proteins were washed, eluted using increasing concentrations of imidazole (10–40mM) and analyzed by SDS-PAGE. In a second set of pull-down assays, His₆-STIM1 C terminus was used to pull down ORA1 N- and C-terminal fragments expressed as GST fusion proteins. The His₆-STIM1 C terminus protein was purified from transiently transfected HEK293 cells using the MagneHis™ Protein Purification System. (3781)

Notes: One potential source of antibiotic-resistant bacteria is food-producing animals. The authors examined the ability of protegrin-1 (PG-1), an antimicrobial peptide, to protect wildtype and transgenic mice expressing PG-1 against bacterial infection. As part of the cloning strategy to produce the PG-1 expression construct, the authors amplified and cloned full-length PG-1 into the pGEM^®-T Easy Vector. To test the bactericidal activity of PG-1 expressed in transgenic mice, radial diffusion assays were performed, in which test samples were added to a well containing E. coli and the clear antibacterial zone was measured. Two of the test samples were neutrophil secretions from the PG-1 transgenic mice and purified polyhistidine-tagged PG-1 protein, purified using the MagneHis™ Protein Purification System. (3896)

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: The authors designed a high-throughput gene-expression screen to identify compounds that induce a neuroblastoma gene signature in BE(2)-C cells. The screen used Valproic Acid (VPA), an inhibitor of histone deacetylase, as an enhancer. The top hit from the screen was all-trans retinoic acid (ATRA). The authors proposed that ATRA + VPA would reduce cell viability and might induce apoptosis by inducing genes associated with terminal differentiation. They used the CellTiter-Glo^® Luminescent Cell Viability Assay in a 96-well format to assess the effects of ATRA and a variety of inhibitors of histone deacetylase on BE(2)-C cell viability. (3931)

Notes: Thees authors searched for small-molecule inhibitors of galactokinase (GALK). They developed an HTS assay using the Kinase-Glo^® Assay System. The HTS assay used 15 μM ATP and α-D-galactose as the substrate and was performed in 384-well plates against 50,000 small molecules. Two hundred compounds were identified from the primary screen as GALK inhibitors. (3934)

Notes: The authors describe an HTS assay to screen for inhibitors of measles virus infection. The CytoTox 96^® Non-Radioactive Cytotoxicity Assay was used to assess toxicity of all confirmed hit compounds from the primary screen. A luminescent assay was used to assess cell-to-cell fusion in the presence candidate compounds that appeared to inhibit entry. Effector cells that expressed the T7 polymerase and measles virus H and F envelope proteins were overlaid on target cells expressing firefly luciferase under the control of a T7 polymerase promoter. Inhibition of fusion should reduce luciferase expression compared to a positive fusion control. Ten of the eleven compounds tested caused a dose-dependent reduction in luciferase expression, suggesting they block viral entry into cells. Luminescence was detected using the Bright-Glo™ Assay System. (3933)

Notes: This paper demonstrates use of a calpain assay in a cell-based format. (Calpain-Glo™ Assay). (3941)

Notes: RBCK1 is a RING-IBR (ring in between ring fingers) protein previously shown to have transcriptional activity and to bind protein Kinase Cβ. This paper demonstrates that RBCK1 also possesses ubiquitin ligase E3 activity. Both FLAG-tag and HaloTag® labeled proteins were used to demonstrate this activity. To demonstrate the interaction between RBCK1 and ubiquitinated proteins, HaloTag®-ubiquitin and FLAG-RBCK1 were coexpressed in HEK293 cells in the presence or absence of a proteasome inhibitor. The anti-FLAG immunoprecipitates isolated from these cells were analyzed by SDS-PAGE and Western blotting using anti-HaloTag® and anti-FLAG antibodies and self-ubiquitination of RBCK1 was demonstrated. RBCK2, a splice variant of RBCK1 lacking the RING domain showed no self ubiquitination activity but was demonstrated to interact with RBCK1 in vivo and in vitro, and to inhibit the self-ubiquitination activity of RBCK1 in a FLAG-tag assay. Pulse-chase experiments, using HEK293 cells expressing HaloTag®-RBCK1 with or without RBCK2 and treated with HaloTag®-TMR ligand, were used to show that the half-life of RBCK1 was extended by overexpression of RBCK2. (3874)

Notes: The authors of this paper investigated the role of Sox2 in neuronal differentiation. Neurospheres were derived from the brains of normal and Sox2 hyphomorphic mice and used to generate differentiated neural cells. In astroglia from cultures containing a Sox2-GFP-expressing lentivirus, ectopic expression of Sox2 correlated with reduced GFAP expression. The authors investigated the role of Sox2 by amplifying binding sites upstream of the GFAP promoter and cloning them upstream of the thymidine kinase promoter in the pRL-TK vector. The Dual-Luciferase Assay System was used to analyze the effect of Sox2 expression on the luciferase reporter gene. The DeadEnd™ Fluorometric TUNEL System was also used to assess apoptosis in some of the neurosphere-derived cultures. (3953)

Notes: Trivalent arsenic (As³⁺) induces expression of growth arrest- and DNA damage-induced gene 45α (GADD45α), which interacts with intracellular signaling molecules involved in cell cycle regulation, apoptosis and immune response. To characterize GADD45α mRNA expression patterns, total RNA was isolated from untreated (growing) and As³⁺-treated (arrested) BEAS-2B cells, and GADD45α mRNA was amplified using the AccessQuick™ RT-PCR System. GADD45α mRNA levels were undetectable in growing cells but increased in a time-dependent manner in arrested cells. Reverse transcription was carried out at 45°C for 50 minutes, followed by 35 cycles of PCR. (3766)

Notes: In this article, the researchers explored the role of RAB23 in gastric cancers. Twenty-four hours before transfection, AGS cells (gastric cancer cell line) that expressed RAB23 were seeded into a 24-well plate at a density of 1.8 × 105 cells/ml. To overexpress RAB23, a full-length RAB23 cDNA was cloned into the pCI-neo Mammalian Expression Vector and transfected into AGS cells. The effect of RAB23 overexpression on the cells was determined using a Matrigel invasion assay while protein expression levels were visualized with Western blotting. (3986)

Notes: The authors investigated the ability of α9β1 integrin to act as a neurotrophin receptor and affect cell signaling pathways. As part of the study, RT-PCR was used to detect the presence of other neurotrophin receptors in their model cell line, SW480. Reverse transcription was performed using the Reverse Transcription System and 1µg of total RNA isolated using the SV Total RNA Isolation System. The resulting cDNA (5µg) was amplified for 35 cycles (β-actin as a control) or 40 cycles (TrkA and p75^NTR) using GoTaq® Green Master Mix. RT-PCR results were confirmed by Western blot analysis. (3884)

Notes: The authors characterized the network of protein-protein interactions for 22 MADS-domain proteins in tomato using yeast two-hybrid and three-hybrid assays. To construct bait and prey proteins, total RNA from various tissues was reverse transcribed using the Reverse Transcription System, then amplified using PCR primers containing restriction enzyme sites for cloning into the bait and prey vectors. (3886)