Chlamydomonas reinhardtii cDNAs upregulated in low-CO2 conditions: expression and analyses

1998 ◽  
Vol 76 (6) ◽  
pp. 1003-1009
Author(s):  
Aravind Somanchi ◽  
Eric R Handley ◽  
James V Moroney
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Chlamydomonas Reinhardtii ◽  
Key Words ◽  
Cdna Clones ◽  
Low Co2 ◽  
Unicellular Algae ◽  
Concentrating Mechanism ◽  
Inducible Genes

Unicellular algae acquire the ability to raise their internal CO2 concentrations under low-CO2 conditions because of the presence of a CO2 concentrating mechanism (CCM). In Chlamydomonas reinhardtii, this mechanism is induced when cells grown in high-CO2 conditions are switched to low-CO2 conditions. To elucidate the genes and proteins involved in this mechanism, we constructed a cDNA library from low CO2 adapted cells and differentially screened the library for cDNAs upregulated under low-CO2 conditions. Earlier studies identified six classes of clones specific to low CO2 adapting cells. To identify other genes and proteins playing a role in this mechanism, we have systematically characterized the cDNA clones that appear to be upregulated by low-CO2 adaptation but do not cross-hybridize with the six previously identified classes. We identified seven new classes of clones that are distinctly upregulated in low-CO2 conditions. These clones were checked by Northern analyses, sequencing, and homology studies. One class of clone represents a novel gene, lci 3. We report on the seven classes of clones and the characterization of lci 3.Key words: Chlamydomonas, CO2 concentrating mechanism, gene regulation, inducible genes, gene expression.

scholarly journals Functional Characterization of a Novel Promoter Element Required for an Innate Immune Response in Drosophila

2003 ◽  
Vol 23 (22) ◽  
pp. 8272-8281 ◽  
Author(s):  
Hanna Uvell ◽  
Ylva Engström
Keyword(s):  
Gene Expression ◽  
Antimicrobial Peptide ◽  
Functional Characterization ◽  
Binding Activity ◽  
Innate Immune ◽  
Site Directed Mutagenesis ◽  
Promoter Element ◽  
Peptide Gene ◽  
Inducible Genes

ABSTRACT Innate immune reactions are crucial processes of metazoans to protect the organism against overgrowth of faster replicating microorganisms. Drosophila melanogaster is a precious model for genetic and molecular studies of the innate immune system. In response to infection, the concerted action of a battery of antimicrobial peptides ensures efficient killing of the microbes. The induced gene expression relies on translocation of the Drosophila Rel transcription factors Relish, Dif, and Dorsal to the nucleus where they bind to κB-like motifs in the promoters of the inducible genes. We have identified another putative promoter element, called region 1 (R1), in a number of antimicrobial peptide genes. Site-directed mutagenesis of the R1 site diminished Cecropin A1 (CecA1) expression in transgenic Drosophila larvae and flies. Infection of flies induced a nuclear R1-binding activity that was unrelated to the κB-binding activity in the same extracts. Although the R1 motif was required for Rel protein-mediated CecA1 expression in cotransfection experiments, our data argue against it being a direct target for the Drosophila Rel proteins. We propose that the R1 and κB motifs are targets for distinct regulatory complexes that act in concert to promote high levels of antimicrobial peptide gene expression in response to infection.

scholarly journals The Histone Code of Toxoplasma gondii Comprises Conserved and Unique Posttranslational Modifications

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Sheila C. Nardelli ◽  
Fa-Yun Che ◽  
Natalie C. Silmon de Monerri ◽  
Hui Xiao ◽  
Edward Nieves ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Toxoplasma Gondii ◽  
Posttranslational Modifications ◽  
Epigenetic Modifications ◽  
Histone Code ◽  
Parasitic Infections ◽  
Content Type ◽  
Epigenetic Gene Regulation

ABSTRACT Epigenetic gene regulation has emerged as a major mechanism for gene regulation in all eukaryotes. Histones are small, basic proteins that constitute the major protein component of chromatin, and posttranslational modifications (PTM) of histones are essential for epigenetic gene regulation. The different combinations of histone PTM form the histone code for an organism, marking functional units of chromatin that recruit macromolecular complexes that govern chromatin structure and regulate gene expression. To characterize the repertoire of Toxoplasma gondii histone PTM, we enriched histones using standard acid extraction protocols and analyzed them with several complementary middle-down and bottom-up proteomic approaches with the high-resolution Orbitrap mass spectrometer using collision-induced dissociation (CID), higher-energy collisional dissociation (HCD), and/or electron transfer dissociation (ETD) fragmentation. We identified 249 peptides with unique combinations of PTM that comprise the T. gondii histone code. T. gondii histones share a high degree of sequence conservation with human histones, and many modifications are conserved between these species. In addition, T. gondii histones have unique modifications not previously identified in other species. Finally, T. gondii histones are modified by succinylation, propionylation, and formylation, recently described histone PTM that have not previously been identified in parasitic protozoa. The characterization of the T. gondii histone code will facilitate in-depth analysis of how epigenetic regulation affects gene expression in pathogenic apicomplexan parasites and identify a new model system for elucidating the biological functions of novel histone PTM. IMPORTANCE Toxoplasma gondii is among the most common parasitic infections in humans. The transition between the different stages of the T. gondii life cycle are essential for parasite virulence and survival. These differentiation events are accompanied by significant changes in gene expression, and the control mechanisms for these transitions have not been elucidated. Important mechanisms that are involved in the control of gene expression are the epigenetic modifications that have been identified in several eukaryotes. T. gondii has a full complement of histone-modifying enzymes, histones, and variants. In this paper, we identify over a hundred PTM and a full repertoire of PTM combinations for T. gondii histones, providing the first large-scale characterization of the T. gondii histone code and an essential initial step for understanding how epigenetic modifications affect gene expression and other processes in this organism.

scholarly journals Epigenetic Mechanisms of HIV-1 Persistence

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 514
Author(s):  
Roxane Verdikt ◽  
Olivier Hernalsteens ◽  
Carine Van Lint
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Rational Design ◽  
Therapeutic Interventions ◽  
Regulatory Mechanisms ◽  
Viral Reservoir ◽  
Epigenetic Mechanisms ◽  
Latently Infected ◽  
Hiv 1

Eradicating HIV-1 in infected individuals will not be possible without addressing the persistence of the virus in its multiple reservoirs. In this context, the molecular characterization of HIV-1 persistence is key for the development of rationalized therapeutic interventions. HIV-1 gene expression relies on the redundant and cooperative recruitment of cellular epigenetic machineries to cis-regulatory proviral regions. Furthermore, the complex repertoire of HIV-1 repression mechanisms varies depending on the nature of the viral reservoir, although, so far, few studies have addressed the specific regulatory mechanisms of HIV-1 persistence in other reservoirs than the well-studied latently infected CD4+ T cells. Here, we present an exhaustive and updated picture of the heterochromatinization of the HIV-1 promoter in its different reservoirs. We highlight the complexity, heterogeneity and dynamics of the epigenetic mechanisms of HIV-1 persistence, while discussing the importance of further understanding HIV-1 gene regulation for the rational design of novel HIV-1 cure strategies.

scholarly journals (296) Genetic and Molecular Characterization of Putative Ethylene Mutants in Antirrhinum majus

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1079B-1079
Author(s):  
Leslie Heffron ◽  
Emily Jordan ◽  
Jackie Nugent ◽  
Schuyler Korban
Keyword(s):  
Gene Expression ◽  
Culture Medium ◽  
Regulation Of Gene Expression ◽  
Acc Synthase ◽  
Antirrhinum Majus ◽  
Cdna Clones ◽  
Complementation Groups ◽  
Exogenous Ethylene ◽  
Mutant Lines

Sixteen putative ethylene mutant Antirrhinum majus (snapdragon) lines, derived from 1-aminocyclopropane-1-carboxylic acid (ACC) screening, were crossed in a full diallel that included the wild-type line to determine allelism/complementation groups. Seeds from these crosses were screened on a tissue culture medium containing 5 μM ACC to elucidate the response to exogenous ethylene treatment. Additionally, five of the mutant lines along with an inbred control, from which the mutants were derived, were analyzed using RT-PCR to determine regulation of gene expression in vegetative (roots, shoots, leaves, and sepals) and floral (six stages of flowering, from green bud to post-pollination) tissues using six different ACC synthase (ACS) cDNA clones and two different ethylene receptor (ETR) cDNA clones, all derived from Antirrhinum majus, as probes. Differential regulation of gene expression for ACS and ETR were observed in some tissues and at different stages of floral development.

scholarly journals Light and Low-CO2-Dependent LCIB–LCIC Complex Localization in the Chloroplast Supports the Carbon-Concentrating Mechanism in Chlamydomonas reinhardtii

2010 ◽  
Vol 51 (9) ◽  
pp. 1453-1468 ◽  
Author(s):  
Takashi Yamano ◽  
Tomoki Tsujikawa ◽  
Kyoko Hatano ◽  
Shin-ichiro Ozawa ◽  
Yuichiro Takahashi ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Carbon Concentrating Mechanism ◽  
Low Co2 ◽  
Concentrating Mechanism
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