Biomedical subjects

Jamie Liu

Publications and source records attributed to Jamie Liu.

3 recordsLinked to original sources

PubMed2007

The use of RNA interference to analyze protein phosphatase function in mammalian cells.

The use of RNA interference to knock down protein phosphatases has proven to be a valuable approach to understanding the functions of these enzymes in mammalian cells. Many protein phosphatases exist as multisubunit and multigene families, which has made it difficult to assess their physiological functions using traditional approaches. The ability to selectively knock down specific subunits and individual isoforms with RNA interference has begun to make it possible to determine the contributions of individual phosphatase proteins to cellular signaling. This chapter describes methods for knocking down protein phosphatases with small interfering RNAs in easily transfectable cells and by the introduction of short-hairpin RNAs into less tractable cells using lentivirus vectors.

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PubMed2006

The alliance for cellular signaling plasmid collection: a flexible resource for protein localization studies and signaling pathway analysis.

Cellular responses to inputs that vary both temporally and spatially are determined by complex relationships between the components of cell signaling networks. Analysis of these relationships requires access to a wide range of experimental reagents and techniques, including the ability to express the protein components of the model cells in a variety of contexts. As part of the Alliance for Cellular Signaling, we developed a robust method for cloning large numbers of signaling ORFs into Gateway entry vectors, and we created a wide range of compatible expression platforms for proteomics applications. To date, we have generated over 3000 plasmids that are available to the scientific community via the American Type Culture Collection. We have established a website at www.signaling-gateway.org/data/plasmid/ that allows users to browse, search, and blast Alliance for Cellular Signaling plasmids. The collection primarily contains murine signaling ORFs with an emphasis on kinases and G protein signaling genes. Here we describe the cloning, databasing, and application of this proteomics resource for large scale subcellular localization screens in mammalian cell lines.

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PubMed2006

A single lentiviral vector platform for microRNA-based conditional RNA interference and coordinated transgene expression.

RNAi is proving to be a powerful experimental tool for the functional annotation of mammalian genomes. The full potential of this technology will be realized through development of approaches permitting regulated manipulation of endogenous gene expression with coordinated reexpression of exogenous transgenes. We describe the development of a lentiviral vector platform, pSLIK (single lentivector for inducible knockdown), which permits tetracycline-regulated expression of microRNA-like short hairpin RNAs from a single viral infection of any naïve cell system. In mouse embryonic fibroblasts, the pSLIK platform was used to conditionally deplete the expression of the heterotrimeric G proteins Galpha12 and Galpha13 both singly and in combination, demonstrating the Galpha13 dependence of serum response element-mediated transcription. In RAW264.7 macrophages, regulated knockdown of Gbeta2 correlated with a reduced Ca(2+) response to C5a. Insertion of a GFP transgene upstream of the Gbeta2 microRNA-like short hairpin RNA allowed concomitant reexpression of a heterologous mRNA during tetracycline-dependent target gene knockdown, significantly enhancing the experimental applicability of the pSLIK system.

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