排序方式: 共有193条查询结果,搜索用时 31 毫秒
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Victoire Cardot‐Ruffino Vronique Chauvet Cassandre Caligaris Adrien Bertrand‐Chapel Nicolas Chuvin Roxane M. Pommier Ulrich Valcourt David Vincent Sylvie Martel Sophie Aires Bastien Kaniewski Pierre Dubus Philippe Cassier Stphanie Sentis Laurent Bartholin 《Genesis (New York, N.Y. : 2000)》2020,58(5)
Recombination systems represent a major breakthrough in the field of genetic model engineering. The Flp recombinases (Flp, Flpe, and Flpo) bind and cleave DNA Frt sites. We created a transgenic mouse strain ([Fsp1‐Flpo]) expressing the Flpo recombinase in fibroblasts. This strain was obtained by random insertion inside mouse zygotes after pronuclear injection. Flpo expression was placed under the control of the promoter of Fsp1 (fibroblast‐specific protein 1) gene, whose expression starts after gastrulation at Day 8.5 in cells of mesenchymal origin. We verified the correct expression and function of the Flpo enzyme by several ex vivo and in vivo approaches. The [Fsp1‐Flpo] strain represents a genuine tool to further target the recombination of transgenes with Frt sites specifically in cells of mesenchymal origin or with a fibroblastic phenotype. 相似文献
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The Serre Ponçon reservoir, in the southern French alps, filled when the dam was completed in 1960. It has meso-eutrophic characteristics. Two hydrobiological studies carried out in 1980 and in 1996 showed interspecific variation in zooplankton and fish communities. A strong development of B. longirostris, D. brachyurum and C. pulchella, characteristic of eutrophic environments, was apparent in 1996, while the population of Daphnia longispina, which was dominant in 1980, had declined. At the same time, strong growth of the bleak Alburnus alburnus, was observed. Research into prey selection over several seasons showed that prey size and density were often a determining factor for capture, e.g., in C. pulchella, D. longispina and C.v. vicinus. However, some small sized rare species such as B. longirostris were also much sought after. 相似文献
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Roxane Simeone Fadel Sayes Okryul Song Matthias I. Gr?schel Priscille Brodin Roland Brosch Laleh Majlessi 《PLoS pathogens》2015,11(2)
Mycobacterium tuberculosis (Mtb) uses efficient
strategies to evade the eradication by professional phagocytes, involving—as
recently confirmed—escape from phagosomal confinement. While
Mtb determinants, such as the ESX-1 type VII secretion system,
that contribute to this phenomenon are known, the host cell factors governing this
important biological process are yet unexplored. Using a newly developed
flow-cytometric approach for Mtb, we show that macrophages
expressing the phagosomal bivalent cation transporter Nramp-1, are much less
susceptible to phagosomal rupture. Together with results from the use of the
phagosome acidification inhibitor bafilomycin, we demonstrate that restriction of
phagosomal acidification is a prerequisite for mycobacterial phagosomal rupture and
cytosolic contact. Using different in vivo approaches including an
enrichment and screen for tracking rare infected phagocytes carrying the CD45.1
hematopoietic allelic marker, we here provide first and unique evidence of M.
tuberculosis-mediated phagosomal rupture in mouse spleen and lungs and in
numerous phagocyte types. Our results, linking the ability of restriction of
phagosome acidification to cytosolic access, provide an important conceptual advance
for our knowledge on host processes targeted by Mtb evasion
strategies. 相似文献
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Blocked replication forks often need to be processed by recombination proteins prior to replication restart. In Escherichia coli, the UvrD repair helicase was recently shown to act at inactivated replication forks, where it counteracts a deleterious action of RecA. Using two mutants affected for different subunits of the polymerase III holoenzyme (Pol IIIh), we show here that the anti-RecA action of UvrD at blocked forks reflects two different activities of this enzyme. A defective UvrD mutant is able to antagonize RecA in cells affected for the Pol IIIh catalytic subunit DnaE. In this mutant, RecA action at blocked forks specifically requires the protein RarA (MgsA). We propose that UvrD prevents RecA binding, possibly by counteracting RarA. In contrast, at forks affected for the Pol IIIh clamp (DnaN), RarA is not required for RecA binding and the ATPase function of UvrD is essential to counteract RecA, supporting the idea that UvrD removes RecA from DNA. UvrD action on RecA is conserved in evolution as it can be performed in E. coli by the UvrD homologue from Bacillus subtilis, PcrA. 相似文献
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Phthiocerol dimycocerosates (DIM) and phenolglycolipids (PGL) are functionally important surface-exposed lipids of Mycobacterium tuberculosis. Their biosynthesis involves the products of several genes clustered in a 70-kb region of the M. tuberculosis chromosome. Among these products is PpsD, one of the modular type I polyketide synthases responsible for the synthesis of the lipid core common to DIM and PGL. Bioinformatic analyses have suggested that this protein lacks a functional enoyl reductase activity domain required for the synthesis of these lipids. We have identified a gene, Rv2953, that putatively encodes an enoyl reductase. Mutation in Rv2953 prevents conventional DIM formation and leads to the accumulation of a novel DIM-like product. This product is unsaturated between C-4 and C-5 of phthiocerol. Consistently, complementation of the mutant with a functional pks15/1 gene from Mycobacterium bovis BCG resulted in the accumulation of an unsaturated PGL-like substance. When an intact Rv2953 gene was reintroduced into the mutant strain, the phenotype reverted to the wild type. These findings indicate that Rv2953 encodes a trans-acting enoyl reductase that acts with PpsD in phthiocerol and phenolphthiocerol biosynthesis. 相似文献
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Powell NA Ciske FL Cai C Holsworth DD Mennen K Van Huis CA Jalaie M Day J Mastronardi M McConnell P Mochalkin I Zhang E Ryan MJ Bryant J Collard W Ferreira S Gu C Collins R Edmunds JJ 《Bioorganic & medicinal chemistry》2007,15(17):5912-5949
We report the design and synthesis of a series of 6-(2,4-diaminopyrimidinyl)-1,4-benzoxazin-3-ones as orally bioavailable small molecule inhibitors of renin. Compounds with a 2-methyl-2-aryl substitution pattern exhibit potent renin inhibition and good permeability, solubility, and metabolic stability. Oral bioavailability was found to be dependent on metabolic clearance and cellular permeability, and was optimized through modulation of the sidechain that binds in the S3(sp) subsite. 相似文献
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Roxane M Barthélémy Anne Chenuil Samuel Blanquart Jean-Paul Casanova Eric Faure 《BMC evolutionary biology》2007,7(1):146