@article{YanHongChenetal.2013,
  author    = {Yan, Yan and Hong, Ni and Chen, Tiansheng and Li, Mingyou and Wang, Tiansu and Guan, Guijun and Qiao, Yongkang and Chen, Songlin and Schartl, Manfred and Li, Chang-Ming and Hong, Yunhan},
  title     = {p53 Gene Targeting by Homologous Recombination in Fish ES Cells},
  series = {PLoS One},
  volume    = {8},
  journal   = {PLoS One},
  number    = {3},
  doi       = {10.1371/journal.pone.0059400},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133416},
  pages     = {e59400},
  year      = {2013},
  abstract  = {Background: Gene targeting (GT) provides a powerful tool for the generation of precise genetic alterations in embryonic stem (ES) cells to elucidate gene function and create animal models for human diseases. This technology has, however, been limited to mouse and rat. We have previously established ES cell lines and procedures for gene transfer and selection for homologous recombination (HR) events in the fish medaka (Oryzias latipes). Methodology and Principal Findings: Here we report HR-mediated GT in this organism. We designed a GT vector to disrupt the tumor suppressor gene p53 (also known as tp53). We show that all the three medaka ES cell lines, MES1 similar to MES3, are highly proficient for HR, as they produced detectable HR without drug selection. Furthermore, the positive-negative selection (PNS) procedure enhanced HR by similar to 12 folds. Out of 39 PNS-resistant colonies analyzed, 19 (48.7\%) were positive for GT by PCR genotyping. When 11 of the PCR-positive colonies were further analyzed, 6 (54.5\%) were found to be bona fide homologous recombinants by Southern blot analysis, sequencing and fluorescent in situ hybridization. This produces a high efficiency of up to 26.6\% for p53 GT under PNS conditions. We show that p53 disruption and long-term propagation under drug selection conditions do not compromise the pluripotency, as p53-targeted ES cells retained stable growth, undifferentiated phenotype, pluripotency gene expression profile and differentiation potential in vitro and in vivo. Conclusions: Our results demonstrate that medaka ES cells are proficient for HR-mediated GT, offering a first model organism of lower vertebrates towards the development of full ES cell-based GT technology.},
  language  = {en}
}
@article{GaubatzEsterlechnerReichertetal.2013,
  author    = {Gaubatz, Stefan and Esterlechner, Jasmina and Reichert, Nina and Iltzsche, Fabian and Krause, Michael and Finkernagel, Florian},
  title     = {LIN9, a Subunit of the DREAM Complex, Regulates Mitotic Gene Expression and Proliferation of Embryonic Stem Cells},
  series = {PLoS ONE},
  journal   = {PLoS ONE},
  doi       = {10.1371/journal.pone.0062882},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96922},
  year      = {2013},
  abstract  = {The DREAM complex plays an important role in regulation of gene expression during the cell cycle. We have previously shown that the DREAM subunit LIN9 is required for early embryonic development and for the maintenance of the inner cell mass in vitro. In this study we examined the effect of knocking down LIN9 on ESCs. We demonstrate that depletion of LIN9 alters the cell cycle distribution of ESCs and results in an accumulation of cells in G2 and M and in an increase of polyploid cells. Genome-wide expression studies showed that the depletion of LIN9 results in downregulation of mitotic genes and in upregulation of differentiation-specific genes. ChIP-on chip experiments showed that mitotic genes are direct targets of LIN9 while lineage specific markers are regulated indirectly. Importantly, depletion of LIN9 does not alter the expression of pluripotency markers SOX2, OCT4 and Nanog and LIN9 depleted ESCs retain alkaline phosphatase activity. We conclude that LIN9 is essential for proliferation and genome stability of ESCs by activating genes with important functions in mitosis and cytokinesis.},
  language  = {en}
}