33,402 research outputs found
Lateral gene transfer and the complex distribution of insertions in eukaryotic enolase
No full textInsertions and deletions in protein-coding genes are relatively rare events compared with sequence substitutions because they are more likely to alter the tertiary structure of the protein. For this reason, insertions and deletions which are clearly homologous are considered to be stable characteristics of the proteins where they are found, and their presence and absence has been used extensively to infer large-scale evolutionary relationships and events. Recently, however, it has been shown that the pattern of highly conserved, clearly homologous insertions at positions with no other detectable homoplasy can be incongruent with the phylogeny of the genes or organisms in which they are found. One case where this has been reported is in the enolase genes of apicomplexan parasites and ciliates, which share homologous insertions in a highly conserved region of the gene with the apparently distantly related enolases of plants. Here we explore the distribution of this character in enolase genes from the third major alveolate group, the dinoflagellates, as well as two groups considered to be closely related to alveolates, haptophytes and heterokonts. With these data, all major groups of the chromalveolates are represented, and the distribution of these insertions is shown to be far more complicated than previously believed. The incongruence between this pattern, the known evolutionary relationships between the organisms, and enolase phylogeny itself cannot be explained by any single event or type of event. Instead, the distribution of enolase insertions is more likely the product of several forces that may have included lateral gene transfer, paralogy, and/or recombination. Of these, lateral gene transfer is the easiest to detect and some well-supported cases of eukaryote-to-eukaryote lateral transfer are evident from the phylogeny. [ABSTRACT FROM AUTHOR]Peer reviewedfinal article publishedPhylogenyRecombinationLateral transferParalog
Gamma-D crystallin gene (CRYGD) mutation causes autosomal dominant congenital cerulean cataracts
No full textCongenital cataracts are a major cause of bilateral visual impairment in childhood. We mapped the gene responsible for autosomal congenital cerulean cataracts to chromosome 2q33-35 in a four generation family of Moroccan descent. The maximum lod score (7.19 at recombination fraction theta=0) was obtained for marker D2S2208 near the g-crystallin gene (CRYG) cluster. Sequencing of the coding regions of the CRYGA, B, C, and D genes showed the presence of a heterozygous C>A transversion in exon 2 of CRYGD that is associated with cataracts in this family. This mutation resulted in a proline to threonine substitution at amino acid 23 of the protein in the first of the four Greek key motifs that characterise this protein. We show that although the x ray crystallography modelling does not indicate any change of the backbone conformation, the mutation affects a region of the Greek key motif that is important for determining the topology of this protein fold. Our data suggest strongly that the proline to threonine substitution may alter the protein folding or decrease the thermodynamic stability or solubility of the protein. Furthermore, this is the first report of a mutation in this gene resulting in autosomal dominant congenital cerulean cataracts
Use of a murine secreted alkaline phosphatase as a non-immunogenic reporter gene in mice: Murine Alkaline Phosphatase as a Reporter Gene
No full textBackground
The development of any vector system as a gene delivery system requires its optimization in vitro and in vivo . Preliminary studies frequently involve the use of a reporter gene, which allows for the rapid and simple assay of vector function through monitoring expression levels of the reporter gene. However, evaluation of vector efficacy can be compromised by immune responses directed against immunogenic reporter proteins.
Methods
We have cloned a murine secreted alkaline phosphatase (mSEAP), and explored its use as a reporter gene in the context of an early region 1 (E1)‐deleted adenovirus (Ad) vector. Studies involved characterization of gene expression in vitro and in vivo , and immunological responses after gene delivery to mice.
Results
In tissue culture, we show that mSEAP is easily measured quantitatively using a sensitive, commercially available chemiluminescent assay, or visualized directly using histological staining. The level of transgene expression from AdmSEAP was similar to that observed for an Ad vector encoding the human placental secreted alkaline phosphatase (hSEAP). After intravenous administration in mice, AdmSEAP continued to express at high levels for the duration of the experiment (1 month), whereas expression from AdhSEAP declined to background levels over the course of the experiment. Although cytotoxic T‐lymphocytes were not detected against either the murine or human SEAP proteins in mice, antibodies were readily detected against the human protein. No antibodies were detected to mSEAP.
Conclusions
Taken together, these data illustrate that mSEAP is a sensitive, non‐immunogenic reporter gene for preclinical mouse studies. Copyright © 2004 John Wiley & Sons, Ltd
Proline-rich tyrosine kinase 2 mediates gonadotropin-releasing hormone signaling to a specific extracellularly regulated kinase-sensitive transcriptional locus in the luteinizing hormone beta-subunit gene
No full textG protein-coupled receptor regulation of gene transcription primarily occurs through the phosphorylation of transcription factors by MAPKs. This requires transduction of an activating signal via scaffold proteins that can ultimately determine the outcome by binding signaling kinases and adapter proteins with effects on the target transcription factor and locus of activation. By investigating these mechanisms, we have elucidated how pituitary gonadotrope cells decode an input GnRH signal into coherent transcriptional output from the LH beta-subunit gene promoter. We show that GnRH activates c-Src and multiple members of the MAPK family, c-Jun NH2-terminal kinase 1/2, p38MAPK, and ERK1/2. Using dominant-negative point mutations and chemical inhibitors, we identified that calcium-dependent proline-rich tyrosine kinase 2 specifically acts as a scaffold for a focal adhesion/cytoskeleton-dependent complex comprised of c-Src, Grb2, and mSos that translocates an ERK-activating signal to the nucleus. The locus of action of ERK was specifically mapped to early growth response-1 (Egr-1) DNA binding sites within the LH beta-subunit gene proximal promoter, which was also activated by p38MAPK, but not c-Jun NH2-terminal kinase 1/2. Egr-1 was confirmed as the transcription factor target of ERK and p38MAPK by blockade of protein expression, transcriptional activity, and DNA binding. We have identified a novel GnRH-activated proline-rich tyrosine kinase 2-dependent ERK-mediated signal transduction pathway that specifically regulates Egr-1 activation of the LH beta-subunit proximal gene promoter, and thus provide insight into the molecular mechanisms required for differential regulation of gonadotropin gene expression
Diasporas of the so-called anthropocene:notes in the margins of "The Anthropocene Atlas of Geneva"
No full textGene Ray calls for a post-modernism that would fully overcome capitalist modernity and its catastrophes. From a reading of Walter Benjamin’s Thesis on the Philosophy of History and Trauerspiel, Ray invokes allegory as an operational mode likely to save the relics of lost fights and inspire future struggles. Art—thought of as a knowledge that uses not only reason but also the senses—must collect these relics lest they become the trophies of the ruling class: in the apocalypse-stricken aboriginal people of America and the devastating effects of the ecological crisis, Ray sees the consequences of the modern progress it pursues. Ray’s sharp reflections follow the completion of the The Anthropocene Atlas of Geneva (TAAG) HEAD-FNS collective research project, in which Ray took part. Amongst other things, TAAG put the little “green” Geneva back into the entanglement of the Anthropocene’s planetary perturbations through movies, documents, and interviews made by artist researchers
A well-conserved Plasmodium falciparum var gene shows an unusual stage-specific transcript pattern
No full textThe var multicopy gene family encodes Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variant antigens, which, through their ability to adhere to a variety of host receptors, are thought to be important virulence factors. The predominant expression of a single cytoadherent PfEMP1 type on an infected red blood cell, and the switching between different PfEMP1 types to evade host protective antibody responses, are processes thought to be controlled at the transcriptional level. Contradictory data have been published on the timing of var gene transcription. Reverse transcription-polymerase chain reaction (RT-PCR) data suggested that transcription of the predominant var gene occurs in the later (pigmented trophozoite) stages, whereas Northern blot data indicated such transcripts only in early (ring) stages. We investigated this discrepancy by Northern blot, with probes covering a diverse var gene repertoire. We confirm that almost all var transcript types were detected only in ring stages. However, one type, the well-conserved varCSA transcript, was present constitutively in different laboratory parasites and does not appear to undergo antigenic variation. Although varCSA has been shown to encode a chondroitin sulphate A (CSA)-binding PfEMP1, we find that the presence of full-length varCSA transcripts does not correlate with the CSA-binding phenotype
Justice afoot
No full textOne night in 1998, a collective amputated the foot of an equestrian statue of Juan de Oñate in New Mexico. In this article, Gene Ray examines the multiple echoes of this iconoclastic act, a reference to the mutilation of indigenous Acoma people 400 years earlier by the Spanish conquistadors, to whom Oñate belonged. This article is for an open source online journal under Creative Commons Non-commercial license. The pdf provided is freely available to anyone for download
Identification and characterization of human PCDH10 gene promoter
No full textRecent studies have suggested roles for PCDH10 as a novel tumor suppressor gene. In our previous work, we located the core promoter of PCDH10 to a 462-bp segment of 5'-flanking region characterized by a high GC content. Here we further identified and characterized the promoter for PCDH10. Transient transfection of PC3 and LNCaP cells with a series of deleted promoter constructs indicated that the minimal promoter region was between nucleotides - 144 and -99. This segment contained a CAAT box, a GT box, and a putative transcription factor binding site for AP-4. Mutational analysis identified that the CAAT box and GT box are necessary for promoter activity. Ectopic expression of NF-Ys increased reporter gene activity, whereas expression of a dominant-negative NF-YA decreased reporter gene activity. Co-transfection of Sp1/Sp3 expression plasmids enhanced reporter gene activity in a dose-dependent manner. Mithramycin A. an inhibitor of Sp-DNA interaction, reduced PCDH10 promoter activity. Electrophoretic mobility shift assays and chromatin immunoprecipitation demonstrated binding of transcription factors Sp1/Sp3 to the promoter region in vitro and in vivo. Our data show that Spl/Sp3 and CBF/NF-Y transcription factors play a crucial role in the basal expression of the human PCDH10 gene. (C) 2011 Elsevier B.V. All rights reserved.Genetics & HereditySCI(E)PubMed10ARTICLE149-5647
Happy Birthday Joseph Beuys - sort of
No full textOn the occasion of the 100th anniversary of German artist Joseph Beuys, the author reflects on the gap between the critical controversies and debates that have characterized the artist's international reception on the one hand and on the other the artist's continuing official approval and celebration in Germany. Drawing on his experiences doing PhD and post-doctoral research on Beuys in Germany and curating a major exhibition and conference on Beuys in the USA, as well as his more recent reinterpretations of the artist's work in the context of the post-1945 rewriting of the sublime, Ray offers a considered and qualified evaluation of the artist's contested legacies
Ode to an empty plinth ::iconoclasm by Other Means
No full textIn a 1997 issue of October journal devoted to the Situationists, T.J. Clark and Donald Nicholson-Smith rejected the narrative that, in the early 1960s, the SI renounced art in favour of politics. In reality, the organisation only renounced conventional and representational forms of art, all the while defending the utopian dimension of the artistic project. Gene Ray develops this argument by relying on the action of the Situationists at the Place de Clichy in Paris, where they tried to reinstall a statue of Fourier
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