Search results for "Plasmids"
showing 10 items of 209 documents
Double In Utero Electroporation to Target Temporally and Spatially Separated Cell Populations.
2020
In utero electroporation is an in vivo DNA transfer technique extensively used to study the molecular and cellular mechanisms underlying mammalian corticogenesis. This procedure takes advantage of the brain ventricles to allow the introduction of DNA of interest and uses a pair of electrodes to direct the entrance of the genetic material into the cells lining the ventricle, the neural stem cells. This method allows researchers to label the desired cells and/or manipulate the expression of genes of interest in those cells. It has multiple applications, including assays targeting neuronal migration, lineage tracing, and axonal pathfinding. An important feature of this method is its temporal a…
Evolution of the leucine gene cluster in Buchnera aphidicola: insights from chromosomal versions of the cluster.
2004
ABSTRACT In Buchnera aphidicola strains associated with the aphid subfamilies Thelaxinae, Lachninae, Pterocommatinae, and Aphidinae, the four leucine genes ( leuA , - B , - C , and - D ) are located on a plasmid. However, these genes are located on the main chromosome in B. aphidicola strains associated with the subfamilies Pemphiginae and Chaitophorinae. The sequence of the chromosomal fragment containing the leucine cluster and flanking genes has different positions in the chromosome in B. aphidicola strains associated with three tribes of the subfamily Pemphiginae and one tribe of the subfamily Chaitophorinae. Due to the extreme gene order conservation of the B. aphidicola genomes, the v…
TFIIH Operates through an Expanded Proximal Promoter To Fine-Tune c-myc Expression
2004
A continuous stream of activating and repressing signals is processed by the transcription complex paused at the promoter of the c-myc proto-oncogene. The general transcription factor IIH (TFIIH) is held at promoters prior to promoter escape and so is well situated to channel the input of activators and repressors to modulate c-myc expression. We have compared cells expressing only a mutated p89 (xeroderma pigmentosum complementation group B [XPB]), the largest TFIIH subunit, with the same cells functionally complemented with the wild-type protein (XPB/wt-p89). Here, we show structural, compositional, and functional differences in transcription complexes between XPB and XPB/wt-89 cells at t…
Chromosomal stasis versus plasmid plasticity in aphid endosymbiont Buchnera aphidicola.
2005
The study of three genomes of the aphid endosymbiont Buchnera aphidicola has revealed an extraordinary stasis: conservation of gene order and genetic composition of the chromosome, while the chromosome size and number of genes has reduced. The reduction in genome size appears to be ongoing since some lineages we now know to have even smaller chromosomes than the first B. aphidicola analysed. The current sequencing by our group of one of these smaller genomes with an estimated size of 450 kb, and its comparison with the other three available genomes provide insights into the nature of processes involved in shrinkage. We discuss whether B. aphidicola might be driven to extinction and be repla…
Aryl hydrocarbon receptor activation by cAMP vs. dioxin: divergent signaling pathways.
2005
Even before the first vertebrates appeared on our planet, the aryl hydrocarbon receptor ( AHR ) gene was present to carry out one or more critical life functions. The vertebrate AHR then evolved to take on functions of detecting and responding to certain classes of environmental toxicants. These environmental pollutants include polycyclic aromatic hydrocarbons (e.g., benzo[ a ]pyrene), polyhalogenated hydrocarbons, dibenzofurans, and the most potent small-molecular-weight toxicant known, 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD or dioxin). After binding of these ligands, the activated AHR translocates rapidly from the cytosol to the nucleus, where it forms a heterodimer with aryl hydroc…
Molecular basis of the functional distinction between Cln1 and Cln2 cyclins
2012
Cln1 and Cln2 are very similar but not identical cyclins. In this work, we tried to describe the molecular basis of the functional distinction between Cln1 and Cln2. We constructed chimeric cyclins containing different fragments of Cln1 and Cln2 and performed several functional analysis that make it possible to distinguish between Cln1 or Cln2. We identified that region between amino acids 225 and 299 of Cln2 is not only necessary but also sufficient to confer Cln2 specific functionality compared with Cln1. We also studied Cln1 and Cln2 subcellular localization identifying additional differences between them. Both cyclins are distributed between the nucleus and the cytoplasm, but Cln1 shows…
Amyloid Precursor-like Protein 1 Influences Endocytosis and Proteolytic Processing of the Amyloid Precursor Protein
2005
Ectodomain shedding of the amyloid precursor protein (APP) is a key regulatory step in the generation of the Alzheimer disease amyloid beta peptide (Abeta). The molecular mechanisms underlying the control of APP shedding remain little understood but are in part dependent on the low density lipoprotein receptor-related protein (LRP), which is involved in APP endocytosis. Here, we show that the APP homolog APLP1 (amyloid precursor-like protein 1) influences APP shedding. In human embryonic kidney 293 cells expression of APLP1 strongly activated APP shedding by alpha-secretase and slightly reduced beta-secretase cleavage. As revealed by domain deletion analysis, the increase in APP shedding re…
Baculovirus capsid display: a novel tool for transduction imaging
2003
Baculoviruses are enveloped insect viruses that can carry large quantities of foreign DNA in their genome. Baculoviruses have proved to be very promising gene therapy vectors but little is known about their transduction mechanisms in mammalian cells. We show in this study that Autographa californica multiple nuclear polyhedrosis virus capsid is compatible with the incorporation of desired proteins in large quantities. Fusions can be made to the N-terminus or C-terminus of the major capsid protein vp39 without compromising the viral titer or functionality. As an example of the baculovirus capsid display we show a tracking of the baculovirus transduction in mammalian cells by an enhanced gree…
Transformation of Aspergillus parasiticus using autonomously replicating plasmids from Aspergillus nidulans.
1994
A genetic transformation system for the aflatoxin-producing fungus Aspergillus parasiticus using two autonomously replicating plasmids from A. nidulans (ARp1 and pDHG25) is reported. Transformation frequencies using the plasmid pDHG25 were from 5 x 10(2) to 2.5 x 10(4) transformants per 10(6) viable protoplasts and microgram DNA. The stability of the plasmids in the transformants was also studied. This transformation system offers a new opportunity to clone genes related to aflatoxin production using appropriate aflatoxin-defective mutants.
Auto-assembly of nanometer thick, water soluble layers of plasmid DNA complexed with diamines and basic amino acids on graphite: Greatest DNA protect…
2017
Abstract We have investigated the ability of diamines as well as basic amino acids to condense DNA onto highly ordered pyrolytic graphite with minimum damage after re-dissolution in water. Based on a bibliographic survey we briefly summarize DNA binding properties with diamines as compared to basic amino acids. Thus, solutions of DNA complexed with these linkers were drop-cast in order to deposit ultra-thin layers on the surface of HOPG in the absence or presence of Tris buffer. Atomic Force Microscopy analyses showed that, at a fixed ligand-DNA mixing ratio of 16, the mean thickness of the layers can be statistically predicted to lie in the range 0–50 nm with a maximum standard deviation ±…