Sleeping beauty: a novel cancer gene discovery tool.
ABSTRACT The National Cancer Institute and the National Human Genome Research Institute recently announced a 3-year 100-million-dollar pilot study to use large-scale resequencing of genes in human tumors to identify new cancer genes. The hope is that some of these genes can be used as drug targets for developing better therapeutics for treating cancer. Although this effort will identify new cancer genes, it could be made more efficient by preferentially resequencing genes identified as novel candidate cancer genes in animal models of cancer. Although retroviral insertional mutagenesis has proven to be an effective tool for identifying novel cancer genes in the mouse, these studies are limited by the fact that retroviral mutagenesis primarily induces hematopoietic and mammary cancer, but little else, while the majority of cancers affecting humans are solid tumors. Recently, two groups have shown that sleeping beauty (SB) transposon-based insertional mutagenesis can also identify novel candidate cancer genes in the mouse. Unlike retroviral infection, SB transposition can be controlled to mutagenize any target tissue and thus potentially induce many different kinds of cancer, including solid tumors. SB transposition in animal models of cancer could therefore greatly facilitate the identification of novel human cancer genes and the development of better cancer therapies.
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ABSTRACT: The PiggyBac (PB) transposon system is a non-viral DNA-transfer system in which a transposase directs integration of a PB transposon into a TTAA site in the genome. Transgenic expression of porcine CD163 is necessary and sufficient to confer non-permissive cells susceptible to infection with porcine reproductive and respiratory syndrome virus (PRRSV). Such permissive cells can be used as a tool for PRRSV cellular receptor and other studies. One of the problems in studying PRRSV is the lack of porcine cell lines. In this study, efficient transfection and expression of porcine CD163 in PK-15 cells by PB transposition was demonstrated. The stable PK-15(CD163) cell line was used in PRRSV infection assays. The data indicated that the average PB transgene copy number per genome was approximately ten. In line with previous literature the integration of PB into the genome had a bias toward the TTAA chromosomal site. The PK-15(CD163) cell line was susceptible to infection by different PRRSV strains and the virus grew to similar titers compared to the Marc-145 cell line. This simplification of PK-15(CD163) cell line production will provide a valuable tool to facilitate PRRSV cellular receptor studies and to accelerate existing vectors for PK-15 cell-based gene transfer and expression.Journal of virological methods 07/2013; 193(2). DOI:10.1016/j.jviromet.2013.06.035 · 2.13 Impact Factor
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ABSTRACT: Chromosome structure and function are influenced by transposable elements, which are mobile DNA segments that can move from place to place. hAT elements are a superfamily of DNA cut and paste elements that move by excision and integration. We have characterized two hAT elements, TcBuster and Space Invaders (SPIN), that are members of a recently described subfamily of hAT elements called Buster elements. We show that TcBuster, from the red flour beetle Tribolium castaneum, is highly active in human cells. SPIN elements are currently inactive elements that were recently highly active in multiple vertebrate genomes, and the high level of sequence similarity across widely diverged species and patchy phylogenetic distribution suggest that they may have moved between genomes by horizontal transfer. We have generated an intact version of this element, SPINON, which is highly active in human cells. In vitro analysis of TcBuster and SPINON shows that no proteins other than transposase are essential for recombination, a property that may contribute to the ability of SPIN to successfully invade multiple organisms. We also analyze the target site preferences of de novo insertions in the human genome of TcBuster and SPINON and compare them with the preferences of Sleeping Beauty and piggyBac, showing that each superfamily has a distinctive pattern of insertion. The high-frequency transposition of both TcBuster and SPINON suggests that these transposon systems offer powerful tools for genome engineering. Finally, we describe a Saccharomyces cerevisiae assay for TcBuster that will provide a means for isolation of hyperactive and other interesting classes of transposase mutants.Proceedings of the National Academy of Sciences 10/2012; DOI:10.1073/pnas.1121543109 · 9.81 Impact Factor