MTrasT24, a metallothionein-ras fusion gene, modulates expression in cultured rat liver cells of two genes associated with in vivo liver cancer.

Li, Yuchi; Seyama, Toshio; Godwin, Andrew K.; Winokur, Thomas S.; Lebovitz, Russell M.; Lieberman, Michael W.

doi:10.1073/pnas.85.2.344

Cited by 46 publications

(19 citation statements)

References 24 publications

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“…These include heavy-metal ions (35,56), steroid hormones (58), tetracycline induction (14,51), and the lac repressor/operator system (4,24). Of these, the lac repressor/operator system is one of the best studied and the specificity of the interactions between the lac repressor/operator and IPTG make it suitable for adaptation to the control of gene expression in mammalian cells.…”

Section: Discussionmentioning

confidence: 99%

Inducible Control of Virulence Gene Expression inListeria monocytogenes: Temporal Requirement of Listeriolysin O during Intracellular Infection

Dancz

Haraga²,

Portnoy

et al. 2002

J Bacteriol

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We have constructed a lac repressor/operator-based system to tightly regulate expression of bacterial genes during intracellular infection by Listeria monocytogenes. An L. monocytogenes strain was constructed in which expression of listeriolysin O was placed under the inducible control of an isopropyl-␤-D-thiogalactopyranoside (IPTG)-dependent promoter. Listeriolysin O (LLO) is a pore-forming cytolysin that mediates lysis of L. monocytogenes-containing phagosomes. Using hemolytic-activity assays and Western blot analysis, we demonstrated dose-dependent IPTG induction of LLO during growth in broth culture. Moreover, intracellular growth of the inducible-LLO (iLLO) strain in the macrophage-like cell line J774 was strictly dependent upon IPTG. We have further shown that iLLO bacteria trapped within primary phagocytic vacuoles can be induced to escape into the cytosol following addition of IPTG to the cell culture medium, thus yielding the ability to control bacterial escape from the phagosome and the initiation of intracellular growth. Using the iLLO strain in plaque-forming assays, we demonstrated an additional requirement for LLO in facilitating cell-to-cell spread in L2 fibroblasts, a nonprofessional phagocytic cell line. Furthermore, the efficiency of cell-to-cell spread of iLLO bacteria in L2 cells was IPTG dose dependent. The potential use of this system for determining the temporal requirements of additional virulence determinants of intracellular pathogenesis is discussed.Listeria monocytogenes is a gram-positive, facultative intracellular bacterial pathogen of humans and animals (13). In humans, L. monocytogenes infections are typically foodborne and cause an invasive and often fatal disease in pregnant women, the elderly, newborns, and immunocompromised individuals (1, 9, 45). Furthermore, L. monocytogenes has been studied for more than 4 decades as a model system for understanding the development of acquired immunity to intracellular pathogens (23,39). The cell biology of L. monocytogenes infection has also been well characterized (55). Following internalization, bacteria are initially contained within host vacuoles but rapidly escape from the vacuoles to enter the cytosol and begin replication. During intracytosolic growth, bacteria exploit a host mechanism of actin-based motility to move within the cytosol and spread from cell to cell without contacting the extracellular environment. Following cell-to-cell spread, a double-membrane vacuole, or secondary vacuole, is formed. Bacteria then lyse the secondary vacuole to continue intracellular growth.〈 thorough understanding of the cell biology of infection, coupled with the development of genetic tools, in vitro tissue culture models, and the mouse model of infection, has made L. monocytogenes an ideal system for elucidating the molecular mechanisms of intracellular pathogenesis. Many of the bacterial determinants necessary for the intracellular growth, spread, and virulence of L. monocytogenes have been identified (40, 57). Since L. monocytogenes is amena...

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Section: Discussionmentioning

confidence: 99%

Inducible Control of Virulence Gene Expression inListeria monocytogenes: Temporal Requirement of Listeriolysin O during Intracellular Infection

Dancz

Haraga²,

Portnoy

et al. 2002

J Bacteriol

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“…All antibodies were diluted (1:50 -1:100) in blocking buffer comprised of Tris-buffered saline (pH 7.6) containing 0.05% triton X-100 and 10% normal horse serum. Positive control cell lines were HepG2 liver epithelial cells stably transfected with mutant human p53, C-5 rat hepatoma cells harboring overexpressed mutant H-ras, 21 and the monocyte cell line HL60, which constitutively expresses high levels of p62myc. 22 Formalin fixed, paraffin embedded blocks of each positive control cell line were prepared, and sections cut from each block were included in each staining reaction.…”

Section: Antibodies and Cell Linesmentioning

confidence: 99%

Expression ofras, c-myc, and p53 proteins in cervical intraepithelial neoplasia

Slagle

Kaufman

Reeves

et al. 1998

Cancer

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“…yGT is also expressed by bile duct epithelium and fetal liver but not by normal adult liver (7). Its expression is elevated in some rat and human hepatocellular cancers (8)(9)(10)(11)(12)(13)(14)(15)(16).…”

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confidence: 99%

Six mRNAs with different 5' ends are encoded by a single gamma-glutamyltransferase gene in mouse.

Rajagopalan

Wan

Habib

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

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MTrasT24, a metallothionein-ras fusion gene, modulates expression in cultured rat liver cells of two genes associated with in vivo liver cancer.

Abstract: We studied the effects of a zinc-inducible metallothionein-ras fusion gene (MTrasT24) in cultured rat liver epithelial (RLE) cells on expression of two genes induced during liver carcinogenesis in vivo: y-glutamyltransferase [(5-

Cited by 46 publications

References 24 publications

Inducible Control of Virulence Gene Expression inListeria monocytogenes: Temporal Requirement of Listeriolysin O during Intracellular Infection

Inducible Control of Virulence Gene Expression inListeria monocytogenes: Temporal Requirement of Listeriolysin O during Intracellular Infection

Expression ofras, c-myc, and p53 proteins in cervical intraepithelial neoplasia

Six mRNAs with different 5' ends are encoded by a single gamma-glutamyltransferase gene in mouse.

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