Search results for " Regulator"
showing 10 items of 728 documents
Autoregulation of NFATc1/A Expression Facilitates Effector T Cells to Escape from Rapid Apoptosis
2002
AbstractThreshold levels of individual NFAT factors appear to be critical for apoptosis induction in effector T cells. In these cells, the short isoform A of NFATc1 is induced to high levels due to the autoregulation of the NFATc1 promoter P1 by NFATs. P1 is located within a CpG island in front of exon 1, represents a DNase I hypersensitive chromatin site, and harbors several sites for binding of inducible transcription factors, including a tandemly arranged NFAT site. A second promoter, P2, before exon 2, is not controlled by NFATs and directs synthesis of the longer NFATc1/B+C isoforms. Contrary to other NFATs, NFATc1/A is unable to promote apoptosis, suggesting that NFATc1/A enhances eff…
A Nullclines Approach to the Study of 2D Artificial Network
2019

 
 The system of two the first order ordinary differential equations arising in the gene regulatory networks theory is studied. The structure of attractors for this system is described for three important behavioral cases: activation, inhibition, mixed activation-inhibition. The geometrical approach combined with the vector field analysis allows treating the problem in full generality. A number of propositions are stated and the proof is geometrical, avoiding complex analytic. Although not all the possible cases are considered, the instructions are given what to do in any particular situation.
Network dynamics of eukaryotic LTR retroelements beyond phylogenetic trees
2009
Abstract Background Sequencing projects have allowed diverse retroviruses and LTR retrotransposons from different eukaryotic organisms to be characterized. It is known that retroviruses and other retro-transcribing viruses evolve from LTR retrotransposons and that this whole system clusters into five families: Ty3/Gypsy, Retroviridae, Ty1/Copia, Bel/Pao and Caulimoviridae. Phylogenetic analyses usually show that these split into multiple distinct lineages but what is yet to be understood is how deep evolution occurred in this system. Results We combined phylogenetic and graph analyses to investigate the history of LTR retroelements both as a tree and as a network. We used 268 non-redundant …
Founder mutations in BRCA1 and BRCA2 genes
2007
BRCA1 and BRCA2 germline mutations contribute to a significant number of familial and hereditary breast and/or ovarian cancers. The proportion of high-risk families with breast and/or ovarian cancer cases due to mutations in these tumor suppressor genes varies widely among populations. In some population, a wide spectrum of different mutations in both genes are present, whereas in other groups specific mutations in BRCA1 and BRCA2 have been reported with high frequency. Most of these mutations are prevalent in restricted populations as consequence of a founder effect. The comparison of haplotypes between families with the same mutation can distinguish whether high-frequency alleles derive f…
Cutting Edge: TGF-β Signaling Is Required for the In Vivo Expansion and Immunosuppressive Capacity of Regulatory CD4+CD25+ T Cells
2004
Abstract Data regarding the role of TGF-β for the in vivo function of regulatory CD4+CD25+ T cells (Treg) are controversial. A transgenic mouse model with impaired TGF-β signaling specifically in T cells was used to assess the role of endogenous TGF-β for the in vivo function of CD4+CD25+ Treg in a murine model of colitis induced by dextran sulfate. Transfer of wild-type, but not transgenic CD4+CD25+ Treg was found to suppress colitis in wild-type mice. In addition, by transferring CFSE-labeled CD4+CD25+ Treg we could demonstrate that endogenous TGF-β promotes the expansion of CD4+CD25+ Treg in vivo. Transgenic mice themselves developed reduced numbers of peripheral CD4+CD25+ Treg and were …
A key pathogenic role for the STAT1/T-bet signaling pathway in T-cell-mediated liver inflammation.
2003
TH1 cytokines have been suggested to contribute to the pathogenesis of T-cell-mediated liver injury and inflammation. However, the molecular signaling pathways involved in such injury are still poorly understood. In the present study, we investigated the role of the STAT1/T-bet signaling pathway in a murine model of T-cell-mediated liver inflammation induced by the application of concanavalin A (Con A) using newly created STAT1 transgenic mice as well as STAT1- and T-bet-deficient mice. Liver injury induced by Con A was associated with an increase of both pSTAT1 and T-bet levels in the liver. Furthermore, functional studies suggested a pathogenic role for STAT1 in Con A-induced liver injury…
Gene Duplication Models and Reconstruction of Gene Regulatory Network Evolution from Network Structure
2016
The work was supported by Latvian Council of Science grant 258/2012 and Latvian State Research programme project NexIT (2014-2017).
A novel approach to CFTR mutation testing by pyrosequencing-based assay panels adapted to ethnicities.
2009
Abstract Background: Cystic fibrosis (CF) is a common autosomal recessive genetic disorder caused by a variety of sequence alterations in the CFTR gene [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)]. Because the relative prevalence of mutations strongly depends on the ethnic background, first-level testing of CF as defined by recent consensus recommendations ought to be adaptable to the ethnicity of patients. Methods: We therefore developed and implemented a diagnostic approach to first-level testing for CF based on published mutation frequencies and Pyrosequencing (PSQ) technology that we complemented with standard procedures of mutation…
Modulation of lipid metabolism and colonic microbial diversity of high-fat-diet C57BL/6 mice by inulin with different chain lengths
2019
Abstract The physicochemical properties, biological functions and microbial degradation of inulins differ according to their degree of polymerization. However, the relationship between inulin activities and its effect on gut microbiota remains unknown. In this study, high fat diet with inulin (1 or 5 g/kg·bw), either with short or long chains groups were administered to different groups of mice (n = 10) for 10 weeks in order to investigate the effect of inulin on the microbial diversity of the animals. Litchi pericarp procyanidins (LPPC) were used for comparison purposes. Furthermore, the lipid metabolism and key regulator genes in mice were determined. The results indicated that natural in…
Functional citric acid cycle in an arcA mutant of Escherichia coli during growth with nitrate under anoxic conditions
1998
The operation of the citric acid cycle of Escherichia coli during nitrate respiration (anoxic conditions) was studied by measuring end products and enzyme activities. Excretion of products other than CO2, such as acetate or ethanol, was taken as an indication for a non-functional cycle. From glycerol, approximately 0.3 mol acetate was produced; the residual portion was completely oxidized, indicating the presence of a partially active citric acid cycle. In an arcA mutant devoid of the transcriptional regulator ArcA, glycerol was completely oxidized with nitrate as an electron acceptor, demonstrating derepression and function of the complete pathway. Glucose, on the other hand, was excreted …