Publications by authors named "Henrike Siemen"

Coordinated mRNA translation at the synapse is increasingly recognized as a critical mechanism for neuronal regulation. Pumilio, a translational regulator, is known to be involved in neuronal homeostasis and memory formation in Drosophila. Most recently, the mammalian Pumilio homolog Pumilio-2 (Pum2) has been found to play a role in the mammalian nervous system, in particular in regulating morphology, arborization and excitability of neuronal dendrites, in vitro.

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Human embryonic stem cells (HESCs) are widely used as a model system for human cell type specification. Genetic modification forms a valuable tool for HESC technology, as it provides the basis for lineage selection, i.e.

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The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue-nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3.

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The steadily increasing availability of human embryonic stem (hES) cell lines has created strong interest in applying available tools for gene transfer in murine cells to human systems. Here we present a method for the transduction of hES cells with ecotropic retroviral vectors. hES cells were transiently transfected with a construct carrying the murine retrovirus receptor mCAT1.

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The biomedical application of human embryonic stem (hES) cells will increasingly depend on the availability of technologies for highly controlled genetic modification. In mouse genetics, conditional mutagenesis using site-specific recombinases has become an invaluable tool for gain- and loss-of-function studies. Here we report highly efficient Cre-mediated recombination of a chromosomally integrated loxP-modified allele in hES cells and hES cell-derived neural precursors by protein transduction.

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Human embryonic stem (hES) cells provide an important tool for the study of human development, disease, and tissue regeneration. Technologies for efficient genetic modification are required to exploit hES cells fully for these applications. Here we present a customized protocol for the transfection of hES cells with the Nucleofector technology and compare its efficiency with conventional electroporation and lipofection.

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Mouse embryonic stem cells can differentiate in vitro into cells of the nervous system, neurons and glia. This differentiation mimics stages observed in vivo, including the generation of primitive ectoderm and neurectoderm in embryoid body culture. We demonstrate here that embryonic stem cell lines mutant for components of the Hedgehog signaling cascade are deficient at generating neurectoderm-containing embryoid bodies.

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