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At least 325 records · Page 18Linked to original sources
PubMed2005

Mouse HFE inhibits Tf-uptake and iron accumulation but induces non-transferrin bound iron (NTBI)-uptake in transformed mouse fibroblasts.

Iron-uptake and storage are tightly regulated to guarantee sufficient iron for essential cellular processes and to prevent the production of damaging free radicals. A non-classical class I MHC molecule, the hemochromatosis factor (HFE), has been shown to regulate iron metabolism, potentially via its interaction with the transferrin receptor. Whereas, the effect of human HFE (hHFE) on transferrin/transferrin receptor association, as well as on transferrin receptor recycling and the level of cellular iron pools in various cell lines was analyzed, very little is known about the mouse HFE (mHFE) protein. In the following study, our aim was to analyze in more detail the function of mHFE. Surprisingly, we observed that over-expression of mHFE, but not of hHFE, in a mouse transformed cell line, results in a most significant inhibition of transferrin-uptake which correlated with apoptotic cell death. mHFE inhibited transferrin-uptake immediately following transfection and this inhibition persisted in the surviving stable transfectants. Concomitantly, cellular iron derived from transferrin-iron uptake was dramatically limited. The activation of a non-transferrin bound iron-uptake pathway that functions in the stable mHFE-transfected clones could explain their normal growth curves and survival. The hypothesis that iron starvation can induce iron-uptake by a novel transferrin-independent pathway is discussed.

Animals↗
PubMed1989

[Quantitative determinations of Hp, Pi, Tf and GC in stored blood stains].

Quantitative analysis of serum proteins in blood stains by rocket immunoelectrophoresis showed the following results: Long elution times in processing blood stains do not produce a significantly higher yield of serum proteins in stains, and they increase the risk of structural alteration of protein molecules. The amount of proteins detected decreases with increasing age of blood stains. Some proteins are already altered in stains after a short storage time and are no longer useful for phenotyping. Our results confirm that blood stain material should be processed as soon as possible.

Blood Grouping and Crossmatching↗
PubMed1979

Serum protein polymorphisms in a village community from the Gambia, West Africa (Hp, Tf, and Gc).

Serum samples from 857 inhabitants of the village of Keneba, The Gambia, West Africa, were examined by means of polyacrylamide gel electrophoresis. In 203 cases no haptoglobin could be detected, whilst in the remaining 654 samples the three common haptoglobin phenotypes were found with gene frequencies of 0.651 (Hp1) and 0.349 (Hp2). The D1 transferrin variant gene was found with a frequency of 0.025. In the serum Gc system the fast variant Gc-Ab was detected, the gene frequencies being: Gc1, 0.943; Gc2, 0.044; and GcAb, 0.013.

Alpha-Globulins↗
PubMed1975

Studies on the polymorphism of C3, Tf and Bg in Down's syndrome and other diseases.

The distribution of phenotypes C3, Ff and Bg was investigated in sera of patients with Down's syndrome, oligophrenia, Wilson's disease and heart infarct. Quantitative determination of the concentration of C3 and C4 components of human complement was also carried out in these patients. The results are compared to healthy controls and are discussed with already reported data from other authors. Despite differences in the percentage distribution of various phenotypes in the patients' sera as compared to that of the controls, no statistically significant association could be established.

Complement C3↗
PubMed1984

Recombination between two mouse t haplotypes (tw12tf and tLub-1): mapping of the H-2 complex relative to centromere and tufted (tf) locus.

A monoclonal antibody known to recognize the H-2.m3 specificity is shown to react with the class I H-2 product of tLub-1 but not tw12tf mice. This reagent was used to study the segregation of the H-2 complex in the progeny of tLub-1 +/tw12tf females. The most straightforward interpretation of the results presented here is that these t haplotypes carry an H-2 complex located between the centromere and tufted locus. Possible consequences of such a location with regard to the recombination between t haplotypes and chromosome 17 from laboratory mice are discussed.

Alleles↗
PubMed2005

The effect of beta-carotene and its derivatives on cytotoxicity, differentiation, proliferative potential and apoptosis on the three human acute leukemia cell lines: U-937, HL-60 and TF-1.

The influence of beta-carotene (BC) and its derivatives on differentiation, proliferation and apoptosis in three human acute leukemia cell lines was studied. We investigated: (i) the cellular uptake of BC, (ii) the cytotoxicity, (iii) the effect on cell cycle progression and/or apoptosis. The dose- and time-dependent pattern of cellular BC uptake in all studied cell lines was seen. We did not observe any cytotoxic effect of BC and ATRA in the chosen concentrations. There was only limited effect of BC on gene expression. The microarrray analysis of U-937 cell line exposed to BC for 72 h showed an increased expression of BAX gene. This finding was confirmed by real-time Q-PCR analysis, and supported by a flow cytometry apoptosis tests. We did not observe any influence of studied components on cellular proliferation. The induction of differentiation after incubation with ATRA in HL-60 cells was noted. The induction of cellular apoptosis by BC was seen in all studied cell lines. We demonstrated that BC used in the concentrations achievable in vivo does not affect the proliferation and differentiation process of the studied leukemic cell lines, but can influence and enhance the apoptosis by modulating the expression of the regulatory genes.

Apoptosis↗
PubMed2006

Synergy between Competitive Intelligence (CI), Knowledge Management (KM) and Technological Foresight (TF) as a strategic model of prospecting--the use of biotechnology in the development of drugs against breast cancer.

The aim of this paper is to demonstrate the synergy between Competitive Intelligence, Knowledge Management and Technological Foresight, and to emphasize the proposal of a strategic model of data prospecting as a mechanism to support decision-making in regard to three approaches for sustainable development and innovation: technological, social and economic. The use of biotechnology in the development of drugs against breast cancer is the case study. The article shows the results of data and text mining in specialized medical and patent databases, identifying the most frequently cited drugs, as well as the authors of research, and the inventors of new technology at the beginning of the 21st century. In addition, the study includes reference to Brazilian competence in breast cancer area, the international trends in drugs for treatment of this cancer, leading international institutions and Brazilian competencies. A framework is presented, which could serve as a guide and support for the decision-making process.

Biotechnology↗
PubMed1997

A peptide sequence from the EGF-2 like domain of FVII inhibits TF-dependent FX activation.

We have found that synthetic peptides derived from the two epidermal growth factor-like domains of factor VII are inhibitors of tissue factor dependent factor X activation. Inhibition was most pronounced for a constrained sequence of amino acids corresponding to positions 91-102 of factor VII, Cys-Val-Asn-Glu-Asn-Gly-Gly-Cys-Glu-Gin-Tyr-Cys. The biological activity appeared to be localized to the tripeptide 'motif', Glu-Gln-Tyr, within the larger sequence. The cyclic peptide was also an inhibitor of tissue factor induced coagulation of plasma, using lipidated tissue factor or tissue factor expressed on the surface of living cells. However, it did not interfere with intrinsic coagulation. Inhibition of factor X activation was dose-dependent with an IC50 value of 350 microM. Kinetic analyses revealed non-competitive inhibition with respect to factor X and suggested that the peptide sequence interferes with the factor VII/tissue factor/factor X complex formation and function. A pentapeptide analog of the putative pharmacophore was also a dose-dependent inhibitor of factor X activation with an IC50 value of 560 microM, but the tripeptide, Glu-Gin-Tyr, alone was without effect. Our results suggest a direct role for the second epidermal growth factor-like domain of factor VII, and in particular its loop I, in the formation and function of the factor VII/tissue factor/factor X complex.

Amino Acid Sequence↗
PubMed1998

Amino acids 1-29 of the adenovirus serotypes 12 and 2 E1A proteins interact with rap30 (TF(II)F) and TBP in vitro.

Early region 1A (E1A) gene products of adenoviruses (Ad) play an essential role in both productive infection and cellular transformation. Besides their function to induce the expression of all other adenoviral genes they modulate the expression of specific cellular genes to ensure an efficient viral reproduction. Gene regulatory functions of E1A proteins are mainly located in the conserved regions 1-3 (CRs) and in the non-conserved amino terminal end and are mediated via protein/protein interactions with cellular factors. We could show recently, that the E1A N-terminus (amino acids [aa] 1-29) of oncogenic Ad12 contains a unique 'trans'-activation domain. Here we demonstrate that this region binds to rap30/TF(II)F and to the TATA-box binding protein TBP in vitro. Mutation analyses suggest that binding to rap30 and 'trans'-activation are two independent functions as a mutant which failed to interact with rap30 was still able to induce gene expression with wildtype efficiency. Moreover loss of transcriptional activity does not correlate with a loss of TBP binding suggesting that this association is not necessary for the N-terminal 'trans'-activating activity. Interestingly, aa 1-29 of Ad2 E1A binds also to rap30 indicating that this interaction might be a common feature of E1A proteins from different serotypes.

Adenovirus E1A Proteins↗
PubMed2003

Regulation of differential COUP-TF-coregulator interactions in adrenal cortical steroidogenesis.

Hyperfunctioning adrenocortical adenomas produce excessive amounts of various corticosteroids due to dysregulated expression of steroidogenic enzymes. Since no genetic mutations in steroidogenic enzyme genes have been identified as yet, the dysregulated expression at the transcription level may be crucial. Chicken ovalbumin upstream promoter-transcription factors (COUP-TFs) and steroidogenic factor-1 (SF-1) play key roles in the transcriptional regulation of steroidogenic P450 genes. Transfection studies showed that SF-1 activated and COUP-TFs repressed the transcription of bovine CYP17 gene promoter from the CRS2 element in a mutually exclusive manner in Y-1 cells. The results indicate that COUP-TFs negatively regulate the transcriptional activity of SF-1, a steroidogenic cell-specific activator of various steroidogenic P450 genes. Expression of both COUP-TFI and COUP-TFII was significantly decreased in the cortisol-producing adenomas, in which CYP17 was drastically overexpressed, indicating that decreased expression of COUP-TFs play a key role in overexpression of CYP17 in this type of tumors. We then screened for COUP-TFI-interacting proteins from a cortisol-producing adenoma cDNA library using a yeast two-hybrid system and identified a novel RING finger-containing protein which can function as a coregulator for COUP-TFI. Notably, COUP-TFI activated rather than repressed several target genes including the human CYP11B2 gene promoter, the results of which were opposite to those of the CYP17 promoter. The bifunctional activities of COUP-TFI may be derived from the promoter context and our newly identified COUP-TFI coregulator.

Adrenal Cortex↗