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    This chapter contains sections titled: Introduction Selectable Markers and Public Concern Marker-Free Transformation Technology Transformation without Selectable Marker Specific Issues Associated with Transformation without Selectable Marker Generation of Amylose-Free Potato Lines by Transformation without Selectable Marker Marker Elimination Conclusion Acknowledgment References
    Selectable marker
    Citations (19)
    Currently used plant transformation systems require selectable marker genes encoding antibiotic or herbicide resistance, along with the gene of interest, to select transformed cells from a large population of mostly untransformed cells. The continued presence of these selectable markers, especially in food crop, is of increasing public concern. The generation of selectable marker-free transgenic plant is one of the new projects in plant biotechnology research. Two techniques, segregation excision and recombination excision, for removal of selectable marker genes are described in this article. The advances in producing selectable marker-free transgenic plants are reviewed too.
    Selectable marker
    Marker gene
    Citations (0)
    Three selectable marker genes were compared for their efficacy in the production of transgenic wheat plants following microprojectile bombardment of cultured immature embryos. While transformed plants were recovered using the bar (phosphinothricin acetyltransferase) gene in combination with bialaphos, and the aphA (neomycin phosphotransferase) gene in combination with geneticin or paromomycin, no transgenic material was obtained with the hpt (hygromycin phosphotransferase) gene and hygromycin B. Southern analysis revealed single copy as well as multiple copy insertions of the bar and aphA transgenes. Inheritance of these selectable marker genes was demonstrated in the T1 generation progenies.
    Selectable marker
    Marker gene
    Citations (59)
    Selectable marker genes are necessary tools for selecting transformants during transgenic plant production. However, once transformation is accomplished, the presence of these selectable marker genes is no longer necessary and can even be undesirable. Here we describe the successful excision of selectable genes from transgenic plants via the use of a cold inducible ‘gene deletor’ system. During a transformation procedure in tobacco, transgenic plants obtained by selection on kanamycin medium and identified by GUS staining and PCR method. Some shoots regenerated form transgenic tobacco leaves, after cold inducing, were screened for selective marker excision using GUS staining and PCR method, and all the exogenous genes were found to have been eliminated. About 28 - 94% of regenerated plants were marker-free. This excision system, mediated by the cold inducible ‘genedeletor’ system to eliminate a selectable marker gene can be very readily adopted and used to efficiently generate marker-free transgenic plants.
    Selectable marker
    Marker gene
    GUS reporter system
    Kanamycin
    Citations (4)
    Abstract Pichia pastoris is a popular host organism for expressing heterologous proteins, and various expression vectors for this yeast are currently available. Recently, vectors containing novel dominant antibiotic resistance markers have become a strong and developing field of research for this methylotropic yeast strain. We have developed new P. pastoris expression vectors, the pPICKanMX6 and pPICKanMX6α series. These vectors were constructed by replacing the zeocin resistance gene of the pPICZA, B, C and pPICZαA, B and C vectors with the Tn903 kan R marker from pFA6a KanMX6, which confers G‐418 sulphate resistance in P. pastoris . The limits of antibiotic resistance in two transformant yeast strains were investigated, and the selection marker was shown to be stably retained. To demonstrate their usefulness, a gene encoding hexa‐histidine‐tagged green fluorescent protein (GFPH6) was cloned into one of the new vectors and GFP expression examined in P. pastoris cells. The protein expression levels using the pPICKanMX6B vector were comparable with that using the original plasmid, based on zeocin resistance as seen by yeast cell fluorescence. Moreover, GFPH6 was able to be isolated by immobilized metal ion affinity chromatography (IMAC) from lysates of both yeast strains. A model reporter construct has been used to demonstrate successful recombinant protein expression and its subsequent purification using these new vectors. Corresponding vectors can now also be engineered with foreign gene expression under the control of various different promoters, to increase the flexibility of P. pastoris as a cellular factory for heterologous protein production. Copyright © 2009 John Wiley & Sons, Ltd.
    Selectable marker
    Heterologous
    Multiple cloning site
    Expression cassette
    Shuttle vector
    Aequorea victoria
    Marker gene
    Pichia
    Citations (19)
    SUMMARY The species specificity of chick and L cell interferons were studied with respect to uptake and activity in mouse and chick embryo cell cultures. Heterologous interferons conditioned cells for the rapid uptake and accelerated development of the antiviral state for homologous interferons. Heterologous interferons were neither taken up nor antiviral, regardless of whether the cells were conditioned with homologous or heterologous interferons.
    Heterologous