Cloning of the gene encoding cucumber lumazine synthase and an analysis of its promoter activity in cucumber

Promoters are an important regulatory element controlling the temporal and spatial expression of genes; thus, they play a critical role in genetic engineering by controlling target gene expression. Cucumber is a widely planted vegetable with a pleasant flavor and high economic value. However, most genetic engineering studies involving cucumber have utilized the CaMV 35S promoter, which mediates ubiquitous target gene expression. To identify a promoter that is highly expressed in cucumber fruit, total proteins from cucumber fruit were analyzed by two-dimensional gel electrophoresis. One spot which is highly expressed in fruit was sequenced from its N-terminus using the Edman degradation method. A total of 10 amino acids (Ala-Val-Arg-His-Ile-Ala-Gly-Ser-Leu-Ala) were sequenced. Based on these 10 residues, a cDNA fragment 905 bp in length was cloned using 3′- and 5′-RACE. The corresponding gene, which encodes 220 amino acids, showed 65-73% similarity to other plant lumazine synthases without the signal peptide. We also cloned the 2.1-kb upstream promoter sequence of this Cucumis sativus lumazine synthase (CsLS) and analyzed its promoter activity by GUS histochemical and fluorometric assays. Our results indicate that CsLS is highly expressed in cucumber fruit, whereas it is expressed at low levels in cucumber stems and leaves.

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Notch Activation Is an Early and Critical Event during T-Cell Leukemogenesis in Ikaros-Deficient Mice

Molecular and Cellular Biology ◽

10.1128/mcb.26.1.209-220.2006 ◽

2006 ◽

Vol 26 (1) ◽

pp. 209-220 ◽

Cited By ~ 116

Author(s):

Alexis Dumortier ◽

Robin Jeannet ◽

Peggy Kirstetter ◽

Eva Kleinmann ◽

MacLean Sellars ◽

...

Keyword(s):

Gene Expression ◽

Tumor Suppressor ◽

Target Gene ◽

Critical Role ◽

Ectopic Expression ◽

Notch Pathway ◽

Notch Target Gene ◽

Target Gene Expression ◽

T Cell Leukemogenesis ◽

Notch Activation

ABSTRACT The Ikaros transcription factor is both a key regulator of lymphocyte differentiation and a tumor suppressor in T lymphocytes. Mice carrying a hypomorphic mutation (IkL/L) in the Ikaros gene all develop thymic lymphomas. IkL/L tumors always exhibit strong activation of the Notch pathway, which is required for tumor cell proliferation in vitro. Notch activation occurs early in tumorigenesis and may precede transformation, as ectopic expression of the Notch targets Hes-1 and Deltex-1 is detected in thymocytes from young IkL/L mice with no overt signs of transformation. Notch activation is further amplified by secondary mutations that lead to C-terminal truncations of Notch 1. Strikingly, restoration of Ikaros activity in tumor cells leads to a rapid and specific downregulation of Notch target gene expression and proliferation arrest. Furthermore, Ikaros binds to the Notch-responsive element in the Hes-1 promoter and represses Notch-dependent transcription from this promoter. Thus, Ikaros-mediated repression of Notch target gene expression may play a critical role in defining the tumor suppressor function of this factor.

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Liver X Receptors Interact with Corepressors to Regulate Gene Expression

Molecular Endocrinology ◽

10.1210/me.2002-0399 ◽

2003 ◽

Vol 17 (6) ◽

pp. 1019-1026 ◽

Cited By ~ 99

Author(s):

Xiao Hu ◽

Suzhen Li ◽

Jun Wu ◽

Chunsheng Xia ◽

Deepak S. Lala

Keyword(s):

Gene Expression ◽

Nuclear Receptor ◽

Target Gene ◽

Critical Role ◽

Cholesterol Homeostasis ◽

Liver X Receptors ◽

Regulate Gene Expression ◽

Target Gene Expression ◽

X Receptors ◽

Regulate Gene

Abstract Liver X receptors (LXRs) are members of the nuclear receptor superfamily that regulate gene expression in response to oxysterols and play a critical role in cholesterol homeostasis by regulating genes that are involved in cholesterol transport, catabolism, and triglyceride synthesis. Oxysterols and synthetic agonists bind LXRs and activate transcription by recruiting coactivator proteins. The role of LXRs in regulating target gene expression in the absence of ligand is unknown. Here we show that LXRs interact with corepressors, N-CoR (nuclear receptor corepressor) and SMRT (silent mediator of retinoic acid receptor and thyroid receptor), which are released upon binding agonists. The LXR-corepressor interaction is isoform selective, wherein LXRα has a very strong interaction with corepressors and LXRβ only shows weak interaction. LXRs also exhibit a preference for interacting with N-CoR vs. SMRT. Similar to other nuclear receptors, mutations in the LXR helix 3 and 4 region abolish corepressor interaction. Using a transient transfection assay, we demonstrate that LXR represses transcription that can be further increased by cotransfecting N-CoR into cells. Chromatin immunoprecipitation experiments further indicated that N-CoR is recruited onto endogenous LXR target genes, and addition of LXR agonists releases N-CoR from their promoters. Collectively, these results suggest that corepressors play an important role in regulating LXR target gene expression.

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2049-P: The Chd4 Helicase of the Nucleosome Remodeling and Deacetylase Complex Modulates Pdx1 Target Gene Expression In Vitro

Diabetes ◽

10.2337/db20-2049-p ◽

2020 ◽

Vol 69 (Supplement 1) ◽

pp. 2049-P

Author(s):

REBECCA K. DAVIDSON ◽

NOLAN CASEY ◽

JASON SPAETH

Keyword(s):

Gene Expression ◽

Target Gene ◽

Nucleosome Remodeling ◽

Target Gene Expression

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On the way toward regulatable expression systems in acetic acid bacteria: target gene expression and use cases

Applied Microbiology and Biotechnology ◽

10.1007/s00253-021-11269-z ◽

2021 ◽

Author(s):

Philipp Moritz Fricke ◽

Angelika Klemm ◽

Michael Bott ◽

Tino Polen

Keyword(s):

Gene Expression ◽

Acetic Acid ◽

Literature Search ◽

Target Gene ◽

Target Genes ◽

Recombinant Dna ◽

Acetic Acid Bacteria ◽

Homoserine Lactone ◽

Expression Systems ◽

Target Gene Expression

Abstract Acetic acid bacteria (AAB) are valuable biocatalysts for which there is growing interest in understanding their basics including physiology and biochemistry. This is accompanied by growing demands for metabolic engineering of AAB to take advantage of their properties and to improve their biomanufacturing efficiencies. Controlled expression of target genes is key to fundamental and applied microbiological research. In order to get an overview of expression systems and their applications in AAB, we carried out a comprehensive literature search using the Web of Science Core Collection database. The Acetobacteraceae family currently comprises 49 genera. We found overall 6097 publications related to one or more AAB genera since 1973, when the first successful recombinant DNA experiments in Escherichia coli have been published. The use of plasmids in AAB began in 1985 and till today was reported for only nine out of the 49 AAB genera currently described. We found at least five major expression plasmid lineages and a multitude of further expression plasmids, almost all enabling only constitutive target gene expression. Only recently, two regulatable expression systems became available for AAB, an N-acyl homoserine lactone (AHL)-inducible system for Komagataeibacter rhaeticus and an l-arabinose-inducible system for Gluconobacter oxydans. Thus, after 35 years of constitutive target gene expression in AAB, we now have the first regulatable expression systems for AAB in hand and further regulatable expression systems for AAB can be expected. Key points • Literature search revealed developments and usage of expression systems in AAB. • Only recently 2 regulatable plasmid systems became available for only 2 AAB genera. • Further regulatable expression systems for AAB are in sight.

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