Functional characterization of the trypanosome translational repressor SCD6

2013 ◽  
Vol 457 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Marina Cristodero ◽  
Bernd Schimanski ◽  
Manfred Heller ◽  
Isabel Roditi
Keyword(s):  
Functional Characterization ◽  
Stress Granule ◽  
Granule Formation ◽  
Translational Repressor ◽  
And Function

Trypanosomal SCD6 is a general repressor of translation. It is not required for stress granule formation and, unusually, does not interact with the helicase DHH1. We analysed domains involved in the localization and function of TbSCD6 and identified interacting partners.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

scholarly journals Ontogenic, phenotypic, and functional characterization of XCR1+ dendritic cells leads to a consistent classification of intestinal dendritic cells based on the expression of XCR1 and SIRPα

2014 ◽  
Author(s):  
Martina Becker ◽  
Steffen Güttler ◽  
Annabell Bachem ◽  
Evelyn Hartung ◽  
Ahmed Mora ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Functional Characterization ◽  
Cross Presentation ◽  
Intestinal Immune System ◽  
Lineage Marker ◽  
And Function ◽  
First Time

In the past, lack of lineage markers confounded the classification of dendritic cells (DC) in the intestine and impeded a full understanding of their location and function. We have recently shown that the chemokine receptor XCR1 is a lineage marker for cross-presenting DC in the spleen. Now we provide evidence that intestinal XCR1+ DC largely, but not fully, overlap with CD103+ CD11b- DC, the hypothesized correlate of “cross-presenting DC” in the intestine, and are selectively dependent in their development on the transcription factor Batf3. XCR1+ DC are located in the villi and epithelial crypts of the lamina propria of the small intestine, the T cell zones of Peyer’s Patches, and in the T cell zones and sinuses of the draining mesenteric lymph node. Functionally, we could demonstrate for the first time that XCR1+ / CD103+ CD11b- DC excel in the cross-presentation of orally applied antigen. Together, our data show that XCR1 is a lineage marker for cross-presenting DC also in the intestinal immune system. Further, extensive phenotypic analyses reveal that expression of the integrin SIRPα consistently demarcates the XCR1- DC population. We propose a simplified and consistent classification system for intestinal DC based on the expression of XCR1 and SIRPα.

Functional characterization of long-chain prenyl diphosphate synthases from tomato

2013 ◽  
Vol 449 (3) ◽  
pp. 729-740 ◽  
Author(s):  
Matthew O. Jones ◽  
Laura Perez-Fons ◽  
Francesca P. Robertson ◽  
Peter M. Bramley ◽  
Paul D. Fraser
Keyword(s):  
Functional Characterization ◽  
Primary Metabolism ◽  
Virus Induced Gene Silencing ◽  
In Planta ◽  
Constitutive Overexpression ◽  
Prenyl Diphosphate ◽  
And Function ◽  
Leaf Appearance ◽  
Long Chain

The electron transfer molecules plastoquinone and ubiquinone are formed by the condensation of aromatic head groups with long-chain prenyl diphosphates. In the present paper we report the cloning and characterization of two genes from tomato (Solanum lycopersicum) responsible for the production of solanesyl and decaprenyl diphosphates. SlSPS (S. lycopersicum solanesyl diphosphate synthase) is targeted to the plastid and both solanesol and plastoquinone are associated with thylakoid membranes. A second gene [SlDPS (S. lycopersicum solanesyl decaprenyl diphosphate synthase)], encodes a long-chain prenyl diphosphate synthase with a different subcellular localization from SlSPS and can utilize geranyl, farnesyl or geranylgeranyl diphosphates in the synthesis of C45 and C50 prenyl diphosphates. When expressed in Escherichia coli, SlSPS and SlDPS extend the prenyl chain length of the endogenous ubiquinone to nine and ten isoprene units respectively. In planta, constitutive overexpression of SlSPS elevated the plastoquinone content of immature tobacco leaves. Virus-induced gene silencing showed that SlSPS is necessary for normal chloroplast structure and function. Plants silenced for SlSPS were photobleached and accumulated phytoene, whereas silencing SlDPS did not affect leaf appearance, but impacted on primary metabolism. The two genes were not able to complement silencing of each other. These findings indicate a requirement for two long-chain prenyl diphosphate synthases in the tomato.

The quest to achieve the detailed structural and functional characterization of CymA

2012 ◽  
Vol 40 (6) ◽  
pp. 1291-1294 ◽  
Author(s):  
Ricardo O. Louro ◽  
Catarina M. Paquete
Keyword(s):  
Microbial Fuel Cells ◽  
Critical Role ◽  
Functional Characterization ◽  
Shewanella Oneidensis ◽  
Model Organism ◽  
Structural Behaviour ◽  
Metal Compounds ◽  
Potential Applications ◽  
And Function

Shewanella oneidensis MR-1 is a sediment organism capable of dissimilatory reduction of insoluble metal compounds such as those of Fe(II) and Mn(IV). This bacterium has been used as a model organism for potential applications in bioremediation of contaminated environments and in the production of energy in microbial fuel cells. The capacity of Shewanella to perform extracellular reduction of metals is linked to the action of several multihaem cytochromes that may be periplasmic or can be associated with the inner or outer membrane. One of these cytochromes is CymA, a membrane-bound tetrahaem cytochrome localized in the periplasm that mediates the electron transfer between the quinone pool in the cytoplasmic membrane and several periplasmic proteins. Although CymA has the capacity to regulate multiple anaerobic respiratory pathways, little is known about the structure and functional mechanisms of this focal protein. Understanding the structure and function of membrane proteins is hampered by inherent difficulties associated with their purification since the choice of the detergents play a critical role in the protein structure and stability. In the present mini-review, we detail the current state of the art in the characterization of CymA, and add recent information on haem structural behaviour for CymA solubilized in different detergents. These structural differences are deduced from NMR spectroscopy data that provide information on the geometry of the haem axial ligands. At least two different conformational forms of CymA are observed for different detergents, which seem to be related to the micelle size. These results provide guidance for the discovery of the most promising detergent that mimics the native lipid bilayer and is compatible with biochemical and structural studies.

scholarly journals Transfer of human chromosomes via human minisegregant cells into mouse cells and the quantitation of the expression of hypoxanthine phosphoribosyltransferase in the hybrids

1978 ◽  
Vol 30 (1) ◽  
pp. 193-209
Author(s):  
A. Tourian ◽  
R.T. Johnson ◽  
K. Burg ◽  
S.W. Nicolson ◽  
K. Sperling
Keyword(s):  
Specific Activity ◽  
Functional Characterization ◽  
Phosphoglycerate Kinase ◽  
Kinetic Constants ◽  
Heat Inactivation ◽  
Hypoxanthine Phosphoribosyltransferase ◽  
Human Chromosomes ◽  
Intact Cells ◽  
And Function

The behaviour of human cells arrested in mitosis can be severely perturbed so as to generate numerous small minisegregants containing very few chromosomes. These cells can be separated according to size and DNA content and fused with intact cells. In this paper we describe the production and some properties of proliferating cell hybrids generated by fusion of human minisegregant cells derived from a HeLa strain with mouse A9 cells deficient in hypoxanthine phosphoribosyltransferase (HPRT, EC 2.4.2.8). The hybrids were shown to contain up to 10 human chromosomes including a single X. Independently derived hybrid clones were quantitatively characterized and compared with the parental phenotypes with respect to HPRT. Human isozymes of each of the 3 enzymes HPRT, glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and phosphoglycerate kinase (EC 2,7.2.3) were found. Tests to evaluate both structure and function of HPRT were utilized. The specific activity of HPRT of more than 10 hybrids tested was approximately 10% that of the HeLa parent. Structural characterization of HPRT from hybrid cells as evidenced by heat inactivation and electrophoretic mobility results in a ‘human-like’ phenotype. Functional characterization of parental HPRT results in kinetic constants for cofactor and substrate which do not permit distinction of human and of human and mouse enzymes; HPRT from the minisegregant hybrids had normal kinetic constants. The reduced specific activity of HPRT in the hybrids is discussed in terms of the inability of the mouse environment to regulate the full expression of the human structural gene.

Investigating the role of arginine 21 in the structure and function of human [alpha]a-crystallin

2018 ◽  
Author(s):  
◽  
Ashutosh Shripad Phadte
Keyword(s):  
Functional Characterization ◽  
Lens Fiber Cell ◽  
University Of Missouri ◽  
Mutant Proteins ◽  
Plausible Mechanism ◽  
And Function ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Cataractogenesis in the eye lens occurs as a result of protein aggregation. Of the multiple mutations in [alpha]A-crystallins associated with the development of congenital hereditary cataract, three identified mutations target R21 within the N- terminal domain of the protein. On structural and functional characterization of a recently identified mutant of [alpha]A-crystallin, [alpha]A-R21Q, we revealed the contribution of R21 in dictating the interaction of [alpha]A-crystallin with other proteins. [alpha]A-R21Q showed and enhanced chaperone-like function, and increased binding to lens fiber cell membranes. Transduction of mutant proteins in ARPE-19 cells prevented their apoptosis in the presence of oxidative stress, suggesting a role for R21 in modulating the anti-apoptotic function of [alpha]A-crystallin. In addition, the R21Q point mutation rescued the chaperone-like activity of [alpha]A-G98R crystallin as well as palliated [alpha]A-G98R mediated cytotoxicity otherwise observed in transduction experiments. Although another mutation, R157Q rescued the chaperone-like activity of [alpha]A-G98R, the double mutant exhibited a loss of its cytoprotective function. The results therefore implicate an important role of R21 in regulating the functional aspect of [alpha]A-crystallin. [alpha]A-crystallin derived peptides have been shown to prevent non-specific aggregation of unfolding proteins in vitro. We show that the [alpha]A-crystallin derived mini-chaperone (mini-[alpha]A) mediated stabilization of self-aggregating [alpha]A-G98R crystallin and bovine [subscript]-crystallin occurs via compensation of lost surface charge. The observation therefore suggests a plausible mechanism of action of [alpha]A-crystallin derived peptides of therapeutic interest.

scholarly journals Beyond classic editing: innovative CRISPR approaches for functional studies of long non-coding RNA

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Dahlia A Awwad
Keyword(s):  
Genetic Manipulation ◽  
Functional Characterization ◽  
The Novel ◽  
Functional Studies ◽  
Non Coding Rna ◽  
Rna Targeting ◽  
Potential Applications ◽  
And Function ◽  
Long Non Coding Rna

Abstract Long non-coding RNAs (lncRNAs) makeup a considerable part of the non-coding human genome and had been well-established as crucial players in an array of biological processes. In spite of their abundance and versatile roles, their functional characteristics remain largely undiscovered mainly due to the lack of suitable genetic manipulation tools. The emerging CRISPR/Cas9 technology has been widely adapted in several studies that aim to screen and identify novel lncRNAs as well as interrogate the functional properties of specific lncRNAs. However, the complexity of lncRNAs genes and the regulatory mechanisms that govern their transcription, as well as their unique functionality pose several limitations the utilization of classic CRISPR methods in lncRNAs functional studies. Here, we overview the unique characteristics of lncRNAs transcription and function and the suitability of the CRISPR toolbox for applications in functional characterization of lncRNAs. We discuss some of the novel variations to the classic CRISPR/Cas9 system that have been tailored and applied previously to study several aspects of lncRNAs functionality. Finally, we share perspectives on the potential applications of various CRISPR systems, including RNA-targeting, in the direct editing and manipulation of lncRNAs.

Genomic analysis of nucleoside transporters in Diptera and functional characterization of DmENT2, a Drosophila equilibrative nucleoside transporter

2007 ◽  
Vol 28 (3) ◽  
pp. 337-347 ◽  
Author(s):  
Jerry Machado ◽  
Parween Abdulla ◽  
W. J. Brad Hanna ◽  
Arthur J. Hilliker ◽  
Imogen R. Coe
Keyword(s):  
Sequence Similarity ◽  
Functional Characterization ◽  
Genomic Analysis ◽  
Structure And Function ◽  
Nucleoside Transporters ◽  
Nucleoside Transport ◽  
Nucleoside Transporter ◽  
Nucleoside Transport Inhibitors ◽  
And Function

The recent completion of genome sequencing projects in a number of eukaryotes allows comparative analysis of orthologs, which can aid in identifying evolutionary constraints on protein structure and function. Nucleoside transporters (NTs) are present in a diverse array of organisms and previous studies have suggested that there is low protein sequence similarity but conserved structure in invertebrate and vertebrate NT orthologs. In addition, most taxa possess multiple NT isoforms but their respective roles in the physiology of the organism are not clear. To investigate the evolution of the structure and function of NTs, we have extended our previous studies by identifying NT orthologs in the Dipteran Anopheles gambiae and comparing these proteins to human and Drosophila melanogaster (Dm) NTs. In addition, we have functionally characterized DmENT2, one of three putative D. melanogaster ENTs that we have previously described. DmENT2 has broad substrate specificity, is insensitive to standard nucleoside transport inhibitors and is expressed in the digestive tract of late stage embryos based on in situ hybridization. DmENT1 and DmENT2 are expressed in most stages during development with the exception of early embryogenesis suggesting specific physiological roles for each isoform. These data represent the first complete genomic analysis of Dipteran NTs and the first report of the functional characterization of any Dipteran NT.

scholarly journals Construction of Infectious Clones of Begomoviruses: Strategies, Techniques and Applications

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 604
Author(s):  
Mohd Faiz Mat Saad ◽  
Aziz Ramlee Sau ◽  
Muhamad Afiq Akbar ◽  
Syarul Nataqain Baharum ◽  
Ahmad Bazli Ramzi ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Potential Threat ◽  
Dna Viruses ◽  
Viral Genomes ◽  
Agriculture Sector ◽  
Infectious Clones ◽  
And Function ◽  
Virus Genomes ◽  
Considerable Loss

Begomovirus has become a potential threat to the agriculture sector. It causes significant losses to several economically important crops. Given this considerable loss, the development of tools to study viral genomes and function is needed. Infectious clones approaches and applications have allowed the direct exploitation of virus genomes. Infectious clones of DNA viruses are the critical instrument for functional characterization of the notable and newly discovered virus. Understanding of structure and composition of viruses has contributed to the evolution of molecular plant pathology. Therefore, this review provides extensive guidelines on the strategy to construct infectious clones of Begomovirus. Also, this technique’s impacts and benefits in controlling and understanding the Begomovirus infection will be discussed.

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