scholarly journals Molecular cloning and functional characterization of chick lens fiber connexin 45.6.

1994 ◽  
Vol 5 (3) ◽  
pp. 363-373 ◽  
Author(s):  
J X Jiang ◽  
T W White ◽  
D A Goodenough ◽  
D L Paul
Keyword(s):  
Molecular Cloning ◽  
Primary Cultures ◽  
Functional Characterization ◽  
Voltage Sensitivity ◽  
Gap Junctional Intercellular Communication ◽  
Ideal System ◽  
Lens Membranes ◽  
Chick Lens

The avian lens is an ideal system to study gap junctional intercellular communication in development and homeostasis. The lens is experimentally more accessible in the developing chick embryo than in other organisms, and chick lens cells differentiate well in primary cultures. However, only two members of the connexin gene family have been identified in the avian lens, whereas three are known in the mammalian system. We report here the molecular cloning and characterization of the third lens connexin, chick connexin45.6 (ChCx45.6), a protein with a predicted molecular mass of 45.6 kDa. ChCx45.6 was encoded by a single copy gene and was expressed specifically in the lens. There were two mRNA species of 6.4 kilobase (kb) and 9.4 kb in length. ChCx45.6 was a functional connexin protein, because expression in Xenopus oocyte pairs resulted in the development of high levels of conductance with a characteristic voltage sensitivity. Antisera were raised against ChCx45.6 and chick connexin56 (ChCx56), another avian lens-specific connexin, permitting the examination of the distribution of both proteins. Immunofluorescence localization showed that both ChCx45.6 and ChCx56 were abundant in lens fibers. Treatment of lens membranes with alkaline phosphatase resulted in electrophoretic mobility shifts, demonstrating that both ChCx45.6 and ChCx56 were phosphoproteins in vivo.

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 Functional characterization of a full length pregnane X receptor, expression in vivo, and identification of PXR alleles, in Zebrafish (Danio rerio)

2013 ◽  
Vol 142-143 ◽  
pp. 447-457 ◽  
Author(s):  
Afonso C.D. Bainy ◽  
Akira Kubota ◽  
Jared V. Goldstone ◽  
Roger Lille-Langøy ◽  
Sibel I. Karchner ◽  
...  
Keyword(s):  
Danio Rerio ◽  
Functional Characterization ◽  
Pregnane X Receptor ◽  
Full Length ◽  
Receptor Expression

scholarly journals Functional identification of ygiP as a positive regulator of the ttdA-ttdB-ygjE operon

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2129-2135 ◽  
Author(s):  
Taku Oshima ◽  
Francis Biville
Keyword(s):  
Functional Characterization ◽  
Anaerobic Growth ◽  
Functional Identification ◽  
New Members ◽  
E Coli ◽  
Inner Membrane Protein ◽  
Tartrate Dehydratase

Functional characterization of unknown genes is currently a major task in biology. The search for gene function involves a combination of various in silico, in vitro and in vivo approaches. Available knowledge from the study of more than 21 LysR-type regulators in Escherichia coli has facilitated the classification of new members of the family. From sequence similarities and its location on the E. coli chromosome, it is suggested that ygiP encodes a lysR regulator controlling the expression of a neighbouring operon; this operon encodes the two subunits of tartrate dehydratase (TtdA, TtdB) and YgiE, an integral inner-membrane protein possibly involved in tartrate uptake. Expression of tartrate dehydratase, which converts tartrate to oxaloacetate, is required for anaerobic growth on glycerol as carbon source in the presence of tartrate. Here, it has been demonstrated that disruption of ygiP, ttdA or ygjE abolishes tartrate-dependent anaerobic growth on glycerol. It has also been shown that tartrate-dependent induction of the ttdA-ttdB-ygjE operon requires a functional YgiP.

scholarly journals Functional Characterization of the mazEF Toxin-Antitoxin System in the Pathogenic Bacterium Agrobacterium tumefaciens

2021 ◽  
Vol 9 (5) ◽  
pp. 1107
Author(s):  
Wonho Choi ◽  
Yoshihiro Yamaguchi ◽  
Ji-Young Park ◽  
Sang-Hyun Park ◽  
Hyeok-Won Lee ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Physiological Function ◽  
Functional Characterization ◽  
Site Directed Mutagenesis ◽  
In Vitro Assays ◽  
Cell Growth Inhibition ◽  
The Right

Agrobacterium tumefaciens is a pathogen of various plants which transfers its own DNA (T-DNA) to the host plants. It is used for producing genetically modified plants with this ability. To control T-DNA transfer to the right place, toxin-antitoxin (TA) systems of A. tumefaciens were used to control the target site of transfer without any unintentional targeting. Here, we describe a toxin-antitoxin system, Atu0939 (mazE-at) and Atu0940 (mazF-at), in the chromosome of Agrobacterium tumefaciens. The toxin in the TA system has 33.3% identity and 45.5% similarity with MazF in Escherichia coli. The expression of MazF-at caused cell growth inhibition, while cells with MazF-at co-expressed with MazE-at grew normally. In vivo and in vitro assays revealed that MazF-at inhibited protein synthesis by decreasing the cellular mRNA stability. Moreover, the catalytic residue of MazF-at was determined to be the 24th glutamic acid using site-directed mutagenesis. From the results, we concluded that MazF-at is a type II toxin-antitoxin system and a ribosome-independent endoribonuclease. Here, we characterized a TA system in A. tumefaciens whose understanding might help to find its physiological function and to develop further applications.

scholarly journals Porins from plants. Molecular cloning and functional characterization of two new members of the porin family.

1994 ◽  
Vol 269 (41) ◽  
pp. 25754-25760
Author(s):  
K Fischer ◽  
A Weber ◽  
S Brink ◽  
B Arbinger ◽  
D Schünemann ◽  
...  
Keyword(s):  
Molecular Cloning ◽  
Functional Characterization ◽  
New Members

Molecular cloning and functional characterization of CvLCYE, a key enzyme in lutein synthesis pathway in Chlorella vulgaris

2021 ◽  
Vol 55 ◽  
pp. 102246
Author(s):  
Sulin Lou ◽  
Xin Lin ◽  
Chenglong Liu ◽  
Muhammad Anwar ◽  
Hui Li ◽  
...  
Keyword(s):  
Molecular Cloning ◽  
Chlorella Vulgaris ◽  
Functional Characterization ◽  
Key Enzyme

scholarly journals Functional Characterization of Interferon Regulation Element of Hepatitis B virus Genome In Vivo

2012 ◽  
Vol 23 (3) ◽  
pp. 278-285 ◽  
Author(s):  
Feng-Jun Liu ◽  
En-Qiang Chen ◽  
Qiao-Ling Zhou ◽  
Tao-You Zhou ◽  
Cong Liu ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Functional Characterization ◽  
Virus Genome ◽  
B Virus

Identification and functional characterization of legumain in amphioxus Branchiostoma belcheri

2009 ◽  
Vol 30 (3) ◽  
pp. 177-186 ◽  
Author(s):  
Lei Teng ◽  
Hiroshi Wada ◽  
Shicui Zhang
Keyword(s):  
Functional Characterization ◽  
Specific Substrate ◽  
Glycosylation Sites ◽  
Branchiostoma Belcheri ◽  
Hen’S Egg ◽  
Hind Gut ◽  
Catalytic Dyad ◽  
Pepstatin A

Legumain has been reported from diverse sources such as plants, parasites (animals) and mammals, but little is known in the lower chordates. The present study reports the first characterization of legumain cDNA from the protochordate Branchiostoma belcheri. The deduced 435-amino-acid-long protein is structurally characterized by the presence of a putative N-terminal signal peptide, a peptidase_C13 superfamily domain with the conserved Lys123-Gly124-Asp125 motif and catalytic dyad His153 and Cys195 and two potential Asn-glycosylation sites at Asn85 and Asn270. Phylogenetic analysis demonstrates that B. belcheri legumain forms an independent cluster together with ascidian legumain, and is positioned at the base of vertebrate legumains, suggesting that B. belcheri legumain gene may represent the archetype of vertebrate legumain genes. Both recombinant legumain expressed in yeast and endogenous legumain are able to be converted into active protein of ~37 kDa via a C-terminal autocleavage at acid pH values. The recombinant legumain efficiently degrades the legumain-specific substrate Z-Ala-Ala-Asn-MCA (benzyloxycarbonyl-L-alanyl-L-alanyl-L-asparagine-4-methylcoumaryl-7-amide) at optimum pH 5.5; and the enzymatic activity is inhibited potently by iodoacetamide and N-ethylmaleimide, partially by hen's-egg white cystatin, but not by E-64 [trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane], PMSF and pepstatin A. In addition, legumain is expressed in vivo in a tissue-specific manner, with main expression in the hepatic caecum and hind-gut of B. belcheri. Altogether, these results suggest that B. belcheri legumain plays a role in the degradation of macromolecules in food.

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