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  • Embryonic stem cells  (1)
  • Preimplantation development  (1)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 37 (1994), S. 34-47 
    ISSN: 1040-452X
    Keywords: Preimplantation development ; Two-dimensional gel electrophoresis ; PDQUEST ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: High-resolution two-dimensional sodium dodecyl sulfate-polyacrylamide (2D-SDS) gel electrophoresis combined with computerized analysis of gel images was used to construct and analyze protein databases for two stages of preimplantation mouse embryogenesis, the compacted eight-cell stage and the fully expanded blastocyst stage. These stages were chosen for their ease in identification of multiple synchronous embryos. Synchronous cohorts of 30-50 embryos were labelled with L-[35S]methionine for 2 hr. The embryos were then lysed in 30 μl hot SDS sample buffer, and the lysates were stored at -80°C until the gels were run. Five replicates were run for eight-cell embryos, and four for blastocyst-stage embryos. The samples were processed for 2D gel electrophoresis and fluorography; multiple exposures were made. Gel images were analyzed using the PDQUEST system, and databases were constructed. Analysis of the databases for both developmental stages showed high reproducibility of protein spots in multiple gel images. Of 1,674 total spots in eight-cell embryo standards, 〉79% of spots had a percentage error (S.E.M./average) 〈50%, and 〉45% had a percentage error 〈30%. Similarly, of 1,653 total spots in blastocyst-stage embryo standards, 74% of spots had a percentage error 〈50%, and approximately 47% of spots had a percentage error 〈30%. Forty-three spots (approximately 3% of the total spots) were found to be detected only in the eight-cell stage, while 75 spots were detected solely in the blastocyst stage. Sixty-nine proteins showed a greater than threefold increase in isotope incorporation from the eight-cell to the blastocyst stage, with a percentage error 〈50% in both the eight-cell and the blastocyst stages. In contrast, 41 of the proteins showed a decrease during this period. Analysis of the protein databases described in this study has allowed us to document the overall quantitative changes in proteins from the compacted eight-cell stage to the blastocyst stage of mouse preimplantation development. These databases provide a valuable tool for further detailed quantitative analysis of specific proteins associated with developmental events. In addition they will permit analysis of the effects of environmental factors, such as growth factors, on early embryo development. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 42 (1995), S. 173-179 
    ISSN: 1040-452X
    Keywords: Embryonic stem cells ; Insulin ; IGF-I ; IGF-II ; Receptor ; RT-PCR ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Insulin and insulin-like growth factors (IGF-I and -II) are members of a family of growth factors which are known to be developmentally regulated during preimplantation mouse embryogenesis. The physiological actions of the insulin family of growth factors are mediated by interactions with specific cell surface receptors that are detectable on the cells of preimplantation mouse embryos. Mouse embryonic stem (ES) cells are totipotent cells derived directly from the inner cell mass of the blastocyst. ES cells have the ability to differentiate into all three germ layers and have unlimited growth potential under certain culture conditions. The great advantage of ES cells is the ability to obtain large amounts of tissue for biochemical studies as compared with preimplantation embryos. To examine in greater detail the biological actions of the insulin family of growth factors, the expression of their cognate receptors on ES cells was examined. ES cells were cultured in DMEM medium supplemented with leukemia inhibitory factor (LIF) to maintain the undifferentiated state. Receptor expression was evaluated at the mRNA level using the reverse transcription polymerase chain reaction (RT-PCR), and at the protein level by radioactive labeled ligand-receptor binding assay. Using RT-PCR, mRNAs of all three growth factor receptors were detected in ES cells. Messenger RNA from ES cells was reverse transcribed into cDNA by AMV reverse transcriptase at 42°C for 1 hr. The reverse transcription reaction was amplified with Taq polymerase and specific primers for insulin, IGF-I, or IGF-II receptors by PCR. RT-PCR and the control plasmid cDNA PCR products were resolved electrophoretically on 3% agarose gels. Each amplified PCR product showed the predicted correct size. The target sequence of RT-PCR amplified fragments were further verified by restriction enzyme digestion. The expression of receptors at the protein level was confirmed by Scatchard analysis, which showed specific binding of the radiolabeled ligands. This study shows that ES cells may provide a useful model to study the biological actions of the insulin family growth factors. © 1995 wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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