33 research outputs found

    Quantitative Comparison of Constitutive Promoters in Human ES cells

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    BACKGROUND: Constitutive promoters that ensure sustained and high level gene expression are basic research tools that have a wide range of applications, including studies of human embryology and drug discovery in human embryonic stem cells (hESCs). Numerous cellular/viral promoters that ensure sustained gene expression in various cell types have been identified but systematic comparison of their activities in hESCs is still lacking. METHODOLOGY/PRINCIPAL FINDINGS: We have quantitatively compared promoter activities of five commonly used constitutive promoters, including the human β-actin promoter (ACTB), cytomegalovirus (CMV), elongation factor-1α, (EF1α), phosphoglycerate kinase (PGK) and ubiquitinC (UbC) in hESCs. Lentiviral gene transfer was used to ensure stable integration of promoter-eGFP constructs into the hESCs genome. Promoter activities were quantitatively compared in long term culture of undifferentiated hESCs and in their differentiated progenies. CONCLUSION/SIGNIFICANCE: The ACTB, EF1α and PGK promoters showed stable activities during long term culture of undifferentiated hESCs. The ACTB promoter was superior by maintaining expression in 75-80% of the cells after 50 days in culture. During embryoid body (EB) differentiation, promoter activities of all five promoters decreased. Although the EF1α promoter was downregulated in approximately 50% of the cells, it was the most stable promoter during differentiation. Gene expression analysis of differentiated eGFP+ and eGFP- cells indicate that promoter activities might be restricted to specific cell lineages, suggesting the need to carefully select optimal promoters for constitutive gene expression in differentiated hESCs

    Improved Air Quality Forecasting Report ISB52-08. Visualisation of Dual Doppler Lidar data

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    This report ISB52-08 was produced under Project 52 of the Invest to Save Scheme, or ISB. The objective of this project is to improve the ability of air quality forecasts and thus impact on the quality of life in and around urban areas

    Improved Air Quality Forecasting Report ISB52-11. Final report for the ISB-52 project.

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    This report, ISB52-11, was produced under Project 52 of the Invest to Save Budget scheme. The project aim was to advance atmospheric pollution dispersion models with the goal of improving air quality forecasting. Potential users of improved air quality information include members of the public with respiratory problems, managers of health resources deployed to care for them, and people working in the planning cycle to regulate existing and proposed sources of air pollutants