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Vitro Expression (vitro + expression)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	33%

Selected Abstracts

Two conserved domains in regulatory B subunits mediate binding to the A subunit of protein phosphatase 2A

FEBS JOURNAL, Issue 2 2002
Xinghai Li
Protein phosphatase 2A (PP2A) is an abundant heterotrimeric serine/threonine phosphatase containing highly conserved structural (A) and catalytic (C) subunits. Its diverse functions in the cell are determined by its association with a highly variable regulatory and targeting B subunit. At least three distinct gene families encoding B subunits are known: B/B55/CDC55, B,/B56/RTS1 and B,/PR72/130. No homology has been identified among the B families, and little is known about how these B subunits interact with the PP2A A and C subunits. In vitro expression of a series of B56, fragments identified two distinct domains that bound independently to the A subunit. Sequence alignment of these A subunit binding domains (ASBD) identified conserved residues in B/B55 and PR72 family members. The alignment successfully predicted domains in B55 and PR72 subunits that similarly bound to the PP2A A subunit. These results suggest that these B subunits share a common core structure and mode of interaction with the PP2A holoenzyme. [source]

p.Gln200Glu, a putative constitutively active mutant of rod ,-transducin (GNAT1) in autosomal dominant congenital stationary night blindness,,

HUMAN MUTATION, Issue 7 2007
Viktoria Szabo
Abstract Congenital stationary night blindness (CSNB) is a non-progressive Mendelian condition resulting from a functional defect in rod photoreceptors. A small number of unique missense mutations in the genes encoding various members of the rod phototransduction cascade, e.g. rhodopsin (RHO), cGMP phosphodiesterase ,-subunit (PDE6B), and transducin ,-subunit (GNAT1) have been reported to cause autosomal dominant (ad) CSNB. While the RHO and PDE6B mutations result in constitutively active proteins, the only known adCSNB-associa-ted GNAT1 change (p.Gly38Asp) produces an ,-transducin that is unable to activate its downstream effector molecule in vitro. In a multigeneration Danish family with adCSNB, we identified a novel heterozygous C to G transversion (c.598C>G) in exon 6 of GNAT1 that should result in a p.Gln200Glu substitution in the evolutionarily highly conserved Switch 2 region of ,-transducin, a domain that has an important role in binding and hydrolyzing GTP. Computer modeling based on the known crystal structure of transducin suggests that the p.Gln200Glu mutant exhibits impaired GTPase activity, and thereby leads to constitutive activation of phototransduction. This assumption is in line with our results of trypsin protection assays as well as previously published biochemical data on mutants of this glutamine in the GTPase active site of ,-transducin following in vitro expression, and observations that inappropriately activating mutants of various members of the rod phototransduction cascade represent one of the major molecular causes of adCSNB. © 2007 Wiley-Liss, Inc. [source]

Augmentation of osseous phenotypes in vivo with a synthetic peptide

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2007
Xinhua Lin
Abstract The synthetic peptide B2A2-K-NS augmented the in vitro expression of osseous phenotypes when cells were stimulated with BMP-2, an osteoinductive growth factor. B2A2-K-NS significantly enhanced the effects of BMP-2-induced alkaline phosphatase activity and mineralization. In the absence of BMP-2, B2A2-K-NS did not have an effect on these endpoints. Based on these observations, in vivo studies were conducted to evaluate if B2A2-K-NS could augment osseous phenotypes in an osteoinductive environment in which BMP-2 should be present. In one study, human demineralized bone matrix (DBM) was used to generate an osteoinductive environment and the effects of B2A2-K-NS on ectopic mineralization of subcutaneous implants evaluated. In the second study, a noncritical sized defect in rabbit ulnas with inherent reparative capacity was used as the osteoinductive environment and was treated with or without B2A2-K-NS. In the DBM studies, B2A2-K-NS augmented mineralization as determined using a combination of radiographic analysis and von Kossa staining at 4 weeks postimplant. In the rabbit ulna model, B2A2-K-NS significantly increased the radiographic bone density in the defects compared to carrier-only or no-treatment controls after 6 weeks. Histological staining confirmed that B2A2-K-NS generated a pronounced bone repair response. The results are consistent with the hypothesis that B2A2-K-NS augments osseous phenotypes in an osteoinductive environment, and suggests that B2A2-K-NS may have clinical utility. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:531,539, 2007 [source]

Chronic Alcohol Consumption Is Associated With an Increased Cytotoxic Profile of Circulating Lymphocytes That May Be Related With the Development of Liver Injury

ALCOHOLISM, Issue 5 2010
Francisco Javier Laso
Background:, Apoptosis has recently emerged as a key component of acute and chronic liver diseases and it could be related to alcoholic liver disease. In the present study, we attempted to analyze the cytotoxic profile of circulating lymphocytes in chronic alcoholic patients grouped according to ethanol intake status and presence of liver disease. Methods:, We investigate the phenotypic and functional behavior of different compartments of peripheral blood (PB) cytotoxic T and natural killer (NK) cells in chronic alcoholic patients without liver disease and active ethanol intake (AWLD group; n = 22), and in subjects with alcohol liver cirrhosis (ALC group; n = 22). Results:, AWLD patients showed an expansion of both CD4+/CD8+ cytotoxic T cells and NK/T cells, in association with an enhanced cytolytic activity against K562 cells and a higher ability to induce in vitro expression of the pro-apoptotic protein APO2.7 in HepG2 cells. Conversely, ethanol intake in ALC patients was associated with decreased NK cell numbers, a reduced cytotoxic activity against K562 cells without significant changes in the expression of APO2.7, and a pro-fibrotic profile of cytokine secretion. Conclusions:, Overall, our results suggest that alcoholic patients display different phenotypical and functional changes in circulating PB cytotoxic lymphocytes according to the presence of alcoholic liver disease, which could be related to the development and progress of liver injury. [source]

Allergen-induced in vitro expression of IL-18, SLAM and GATA-3 mRNA in PBMC during sublingual immunotherapy

ALLERGY, Issue 8 2007
J. Savolainen
Background:, Signalling lymphocytic activation molecule (SLAM) and interleukin (IL)-18 induce interferon (IFN)-, production from Th1 cells. The allergen-induced SLAM and IL-18 mRNA expressions are increased during subcutaneous immunotherapy (SCIT), but nothing is known about their role during sublingual immunotherapy (SLIT). Transcription factor GATA-3 is associated with Th2 cells but its role in SCIT and SLIT is yet unexplored. This study was undertaken to analyse the allergen induced in vitro mRNA expression of IL-18, SLAM and GATA-3 in peripheral blood mononuclear cells (PBMC) of children with allergic rhinitis (AR) during SLIT. Methods:, Ten patients with AR undergoing pollen SLIT with a weekly dose of 200 000 SQ-U, 10 with 24 000 SQ-U of mixture of Betula verrucosa, Corylus avellana and Alnus glutinosa and 10 with placebo were included. Peripheral blood mononuclear cell were stimulated with birch extract prior to, after 1 and 2 years of the treatment. The mRNA expression was assessed using kinetic real-time RT-PCR (TaqMan®; Applied Biosystems, Foster City, CA, USA). Results:, The expression of IL-18 mRNA was increased in the high-dose group in comparison to the placebo group after 1 year of therapy (P = 0.028) and had an inverse correlation with the late phase skin reaction after the second study year (r = ,0.41, P = 0.041). SLAM mRNA expression increased in the high-dose group from baseline to 1 year (P = 0.028) and correlated with IL-10 (r = 0.96, P < 0.0001) and transforming growth factor-, (r = 0.80, P = 0.0037) mRNA expression. No significant changes were seen in GATA-3 mRNA expression. Conclusions:, During SLIT, IL-18 and SLAM are upregulated, suggesting that the Th2 type inflammatory response is downregulated during SLIT by increased Th1 type response. [source]

Increased surfactant protein-D and foamy macrophages in smoking-induced mouse emphysema

RESPIROLOGY, Issue 2 2007
Noriyuki HIRAMA
Background and objective: The molecular mechanisms underlying COPD remain undetermined. The lungs of surfactant protein-D (SP-D) deficient mice show emphysema and an excessive number of foamy macrophages. This study aims to elucidate roles of SP-D and foamy macrophages in smoking-induced mouse emphysema. Methods: Twenty B6C3F1 mice were exposed to cigarette smoke (2 cigarettes/day/mouse for 6 months). The mice were killed, and formalin-fixed, paraffin-embedded lung sections were carried out on seven mice, BAL was carried out on six mice, and seven mice were used to make lung homogenates. In in vitro studies, A549 cells were transduced with the SP-D expression plasmid and treated with cigarette smoke extract to evaluate cell viability. Results: Emphysema was induced in the mice by chronic cigarette smoke exposure. Increased expression of matrix metalloproteinase-9 and -12 was observed, and foamy alveolar macrophages accumulated in the smoke-exposed lungs. Immunostaining of BAL cells revealed the major source of matrix metalloproteinase-12 to be foamy alveolar macrophages. Furthermore, SP-D was elevated in emphysema lungs. Expression of transcription factors, Fra-1, junB and C/EBP, (which induce SP-D) were significantly elevated in emphysema lungs. The in vitro expression of SP-D gene in A549 cells prolonged cell survival following exposure to cigarette smoke condensate. Conclusions: The accumulation of foamy alveolar macrophages may play a key role in the development of smoking-induced emphysema. Increased SP-D may play a protective role in the development of smoking-induced emphysema, in part by preventing alveolar cell death. [source]