Identification and functional characterization of regulatory elements of the glutamine synthetase gene from rat liver

Fahrner, J.; Labruyère, Wil T.; Gaunitz, Christine; Moorman, Antoon F.M.; Gebhardt, Rolf; Lamers, Wouter H.

doi:10.1111/j.1432-1033.1993.tb17854.x

Cited by 63 publications

(55 citation statements)

References 49 publications

(23 reference statements)

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“…Although transcriptional control elements have been localized to introns (Jeffers and Pellicer, 1992;Fahrner et al, 1993), in other cases it is the processing of the intron that affects the efficiency of gene expression (Luehrsen and Walbot, 1991;Korb, 1993). The evidence suggests that in many cases the efficiency of intron processing directly affects steady-state mRNA levels.…”

Section: Discussionmentioning

confidence: 99%

Isolation of a Polyubiquitin Promoter and Its Expression in Transgenic Potato Plants

Garbarino¹,

Oosumi²,

Belknap³

1995

Plant Physiol.

105

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A polyubiquitin clone (ubi7) was isolated from a potato (Solanum tuberosum) genomic library using a copy-specific probe from a stress-induced ubiquitin cDNA. The genomic clone contained a 569-bp intron immediately 5' to the initiation codon for the first ubiquitin-coding unit. Two chimeric 0-glucuronidase (CUS) fusion transgenes were introduced into potato. The first contained CUS fused to a 1156-bp promoter fragment containing only 5' flanking and 5' untranslated sequences from ubi7. The second transgene contained CUS translationally fused to the carboxy terminus of the first ubiquitin-coding unit and thus included the intron present in the 5' untranslated region of the polyubiquitin gene. Both ubi7-CUS transgenes were activated by wounding in tuber tissue and in leaves by application of exogenous methyl jasmonate. They were also expressed constitutively in the potato tuber peel (outer 1-2 mm). Both transgenes were actively expressed in mature leaves. Exceptionally high levels of expression were observed in senescent leaves. Transgenic clones containing the ubi7 intron and the first ubiquitincoding unit showed GUS expression levels at least 10 times higher than clones containing GUS fused to the intronless promoter.

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Section: Discussionmentioning

confidence: 99%

Isolation of a Polyubiquitin Promoter and Its Expression in Transgenic Potato Plants

Garbarino¹,

Oosumi²,

Belknap³

1995

Plant Physiol.

105

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“…The regulatory elements of the rat GS gene have been characterized (Mill et al 1991;Fahmer et al 1993). The underlying cellular and/or molecular basis for the expression of GS in PC 12 cells is uncertain.…”

Section: Discussionmentioning

confidence: 99%

Signal Transduction and Gene Regulation During Hypoxia Stress: A Potential Role in Neurodegenerative Disease

Millhorn¹

2002

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Public reporting burden for this collection of infomiation is estimated to average 1 hour per response, including the time for reviewing instnjctions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway. Suite 1204, Arlington, VA 22202-4302, and PERFORMING ORGANIZATION NAIVIE(S) AND ADDRESS(ES)University of Cincinnati Cincinnati, Ohio 45267-0553 E-Mail: david.millhorn@uc.edu Soldiers deployed to high altitude terrain or exposed to chemical toxins that induce ischemia or impaired oxidative metabolism in the central nervous system (CNS) encounter sustained cellular hypoxia. This can compromise CNS function and lead to permanent neuronal injury, which is a precursor for neurodegenerative disorders such as Alzheimer's disease. The proposed research is designed to determine the role of stress-activated signal transduction systems in regulating a cellular phenotype that is tolerant to hypoxic stress. We hypothesize that de novo gene expression is a major component of the adaptative/protective response to hypoxia, and that the p38 kinase stress-activated pathway plays a major role in this response. We present novel preliminary findings, which show that genes involved in cell proliferation and differentiation are regulated by hypoxia and p38. We hypothesize that these genes and the genes that encode immediate early transcription factors, and the hypoxia-sensitive potassium channels are regulated by p38 during hypoxia and play a major role in protecting neurons form hypoxia injury and neurodegenerative disease. Studies are performed in PCI2 cells, which are extremely tolerant to reduced oxygen and a widely used model for elucidating the molecular mechanisms of neural function. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)UThe objectives of the proposed research are: 1) Identify the p38 isoforms that are activated by hypoxia. Determine the effects of hypoxia on the protein kinases and small G-proteins that lie upstream of p38. 2) Determine the role of the p38 kinase pathway on the unique hypoxia-induced regulation of cyclin A, and immediate early genes in thsfos and jun families. 3) Determine the role of the p38 kinase pathway in regulating the hypoxia-induced expression of the oxygen-sensitive Kvl.2 potassium channel.14. SUBJECT TERMS hypoxia, p38 kinase pathways, cyclin A, immediate early genes, potassium channels, signal transduction, pheochromocytoma cells, neurodegenerative disease References 10Appendices 10 IntroductionThe research in this project was undertaken to determine the role of stress-activated signal transduction systems in regulating a cellular phenotype that can survive and function during hypoxic stress. The general hypothesis is that reduced 02 c...

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“…HepG2 hepatoblastoma cells were cultured in Dulbecco's modified Eagle's medium (Invitrogen, Eggenstein, Germany) supplemented with 2 mM glutamine, 10% fetal calf serum, 40 U/ml streptomycin, and 50 U/ml penicillin, as described elsewhere (Fahrner et al, 1993). They were passaged every week at the time they reached confluence.…”

Section: Incubations With Human Hepatoblastoma Cells (Hepg2) Cultivamentioning

confidence: 99%

The Oxidative Biotransformation of Losoxantrone (CI-941)

Renner

Piperopoulos²,

Gebhardt³

et al. 2002

Drug Metab Dispos

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ABSTRACT:The oxidative biotransformation of the anticancer drug 7-hydroxy- 2-[2-[(2-hydroxyethyl)amino]ethyl]-5-[[2-[(2-hydroxyethyl)amino]ethyl]amino]anthra[1,9-cd]pyrazol-6(2H)-one dihydrochloride (losoxantrone, CI-941) after incubation of primary cultures of rat hepatocytes has been investigated. The structures of twelve losoxantrone metabolites have been elucidated by means of highperformance liquid chromatography-mass spectometry, tandem mass spectrometry, and two-dimensional NMR. In these mammalian hepatocytes, the CI-941 biotransformation includes a monohydroxylation of the phenolic substructure of the CI-941-chromophore via cytochrome P450 catalysis, resulting in metabolites having an orthoand para-hydroquinonoid substructure, respectively. The identification of a glutathione conjugate as a follow-up metabolite confirms the oxidative activation of the ortho-hydroxylated losoxantrone metabolite. The oxidative activation establishes the ability of CI-941 to form covalent bonds to intracellular nucleophilic targets. Furthermore, the CI-941 metabolism was shown to be extremely suppressed in rat hepatocytes incubated with metyrapone. In contrast to these results, human tumor HepG2 cells did not show any CI-941 biotransformation after incubation., is a member of the novel class of anthrapyrazole anticancer agents. This cytostatic compound is derived from anthracyclines (e.g., doxorubicin and daunorubicin) and mitoxantrone by chromophore modification of the anthracene-9,10-dione unit. In clinical trials (phase I and II), losoxantrone has been shown to be the most powerful anthrapyrazole. It was developed with the intention of diminishing the cardiotoxicity associated with anthracene-9,10-dione drugs. The cardiotoxicity represents the dosis-limiting side effect and is induced by free radicals created during the biotransformation of anthraquinonoid antitumor agents (Murdock et al., 1979;Smith, 1983;Zee-Cheng and Cheng, 1983) (Fig. 1).Both the synthetic preparation and the exceptional in vivo anticancer activity of losoxantrone are well known (Lown, 1983;Showalter et al., 1987;Reszka et al., 1988;Beylin et al., 1989;Fry, 1991;Calvert et al., 1994;Zhang et al., 1994). Several clinical studies of combination regimens with losoxantrone and paclitaxel in patients with advanced breast cancer were recently completed (Kaufman et al., 1998(Kaufman et al., , 1999Diab et al., 1999). Furthermore, the results of a phase II clinical trail in hormone-refractory metastatic prostate cancer were published (Huan et al., 2000).The antitumor activity of losoxantrone, among other biochemical effects against tumor cells, is based on inhibiting the enzyme topoisomerase II (Fry, 1991;Leteurtre et al., 1994). Although numerous studies analyzing the pharmacokinetic behavior of the drug under various conditions were published, the metabolism of anthrapyrazole CI-941 is almost unknown until now. Only a small part of the CI-941 biotransformation, proved by metabolites in human urine Richards and Sun, 1995) and feces (Joshi et al., 2001), was ...

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Identification and functional characterization of regulatory elements of the glutamine synthetase gene from rat liver

Cited by 63 publications

References 49 publications

Isolation of a Polyubiquitin Promoter and Its Expression in Transgenic Potato Plants

Isolation of a Polyubiquitin Promoter and Its Expression in Transgenic Potato Plants

Signal Transduction and Gene Regulation During Hypoxia Stress: A Potential Role in Neurodegenerative Disease

The Oxidative Biotransformation of Losoxantrone (CI-941)

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