SEARCH · PubMed Health

Results for “FOG”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

PubMed2002

Interaction between FOG-1 and the corepressor C-terminal binding protein is dispensable for normal erythropoiesis in vivo.

The hematopoietic, zinc-finger protein FOG-1 is essential for the development of the erythroid and megakaryocytic lineages. FOG-1's function in hematopoiesis is dependent on its ability to interact with the transcription factor GATA-1. FOG-1 has also been observed to interact with the corepressor molecule C-terminal binding protein (CtBP) through a peptide motif shared by all FOG family members. In this study, we confirmed that FOG-1 and CtBP interact by coimmunoprecipitation. We further demonstrate that a FOG-1 mutant unable to interact with CtBP has increased erythropoietic (but not megakaryocytic) rescue (relative to the wild type) of a FOG-1(-/-) cell line. To analyze further the physiological role of the FOG-1-CtBP interaction, we generated knock-in mice that express a FOG-1 variant unable to bind CtBP. Surprisingly, these mice are normal and fertile. Furthermore, erythropoiesis at all stages of development is normal in these mice. Erythrocyte production is similar in mutant and wild-type mice even under conditions of erythropoietic stress stimulated by either exogenously added erythropoietin or phenylhydrazine-induced anemia. Thus, despite conservation of the FOG-CtBP interaction site, the in vivo function of FOG-1 in erythroid development is not affected by its inability to interact with the corepressor CtBP.

Alcohol Oxidoreductases↗

PubMed2006

FOG-1 represses GATA-1-dependent FcepsilonRI beta-chain transcription: transcriptional mechanism of mast-cell-specific gene expression in mice.

Cell-type-specific transcription of mouse high-affinity IgE receptor (FcepsilonRI) beta-chain is positively regulated by the transcription factor GATA-1. Although GATA-1 is expressed in erythroid cells, megakaryocytes, and mast cells, the expression of mouse FcepsilonRI beta-chain is restricted to mast cells. In the present study, we characterized the role of GATA-associated cofactor FOG-1 in the regulation of the FcepsilonRI beta-chain promoter. The expression levels of FOG-1, GATA-1, and beta-chain in each hematopoietic cell line were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. FOG-1 expression was higher in the beta-chain-negative hematopoietic progenitor cell line Ba/F3 than in the beta-chain-positive mast cell line PT18. By contrast, GATA-1 expression was similar when comparing the 2 cell lines. A transient reporter assay demonstrated that the beta-chain promoter functioned in PT18 but not in Ba/F3 and that the transcription activity of the beta-chain promoter in PT18 was markedly suppressed by overexpression of FOG-1. Although the activity of the beta-chain promoter, which was upregulated by coexpression of GATA-1, was significantly suppressed by coexpression of FOG-1 in the simian kidney CV-1 cells (beta-chain(-), GATA-1(-), and FOG-1(-)), the transactivation of the beta-chain promoter by the GATA-1 mutant V205G, which cannot bind FOG-1, was not affected by coexpression of FOG-1. Further, overexpression of FOG-1 in PT18 resulted in decreases in cell surface expression of FcepsilonRI and beta-chain transcription. Finally, suppression of FOG-1 expression using an siRNA approach resulted in increased beta-chain promoter activity in Ba/F3. These results suggest that FOG-1 expression level regulates the GATA-1-dependent FcepsilonRI beta-chain promoter.

Animals↗

PubMed2006

The narrow-leaf syndrome: a functional and evolutionary approach to the form of fog-harvesting rosette plants.

Plants that use fog as an important water-source frequently have a rosette growth habit. The performance of this morphology in relation to fog interception has not been studied. Some first-principles from physics predict that narrow leaves, together with other ancillary traits (large number and high flexibility of leaves, caudices, and/or epiphytism) which constitute the "narrow-leaf syndrome" should increase fog-interception efficiency. This was tested using aluminum models of rosettes that differed in leaf length, width and number and were exposed to artificial fog. The results were validated using seven species of Tillandsia and four species of xerophytic rosettes. The total amount of fog intercepted in rosette plants increased with total leaf area, while narrow leaves maximized interception efficiency (measured as interception per unit area). The number of leaves in the rosettes is physically constrained because wide-leafed plants can only have a few blades. At the limits of this constraint, net fog interception was independent of leaf form, but interception efficiency was maximized by large numbers of narrow leaves. Atmospheric Tillandsia species show the narrow-leaf syndrome. Their fog interception efficiencies were correlated to the ones predicted from aluminum-model data. In the larger xerophytic rosette species, the interception efficiency was greatest in plants showing the narrow-leaf syndrome. The adaptation to fog-harvesting in several narrow-leaved rosettes was tested for evolutionary convergence in 30 xerophytic rosette species using a comparative method. There was a significant evolutionary tendency towards the development of the narrow-leaf syndrome the closer the species grew to areas where fog is frequently available. This study establishes convergence in a very wide group of plants encompassing genera as contrasting as Tillandsia and Agave as a result of their dependence on fog.

Aluminum↗

PubMed1992

Seasonal trend of fog water chemical composition in the Po Valley.

Fog frequency in the Po Valley, Northern Italy, can be as high as 30% of the time in the fall-winter season. High pollutant concentrations have been measured in fog water samples collected in this area over the past few years. The combined effects of high fog occurrence and high pollutant loading of the fog droplets can determine, in this area, appreciable chemical deposition rates. An automated station for fog water collection was developed, and deployed at the field station of S. Pietro Capofiume, in the eastern part of the Po Valley for an extended period: from the beginning of November 1989 to the end of April 1990. Time-resolved sampling of fog droplets was carried out during all fog events occurring in this period, and chemical analyses were performed on the collected samples. Statistical information on fog occurrence and fog water chemical composition is reported in this paper, and a tentative seasonal deposition budget is calculated for H+, NH4+, NO3- and SO4(2-) ions. The problems connected with fog droplet sampling in sub-freezing conditions are also addressed in the paper.

Journal Article↗

PubMed2004

Determining the effects of eyewear fogging on visual task performance.

The effect of fog on eyewear was evaluated by having individuals perform a target detection task in environments that typically cause eyewear to fog while wearing either eyewear that had been treated with anti-fog coating, eyewear not treated, or no eyewear. Detection was higher with eyewear that had been treated with anti-fog coating compared to uncoated lenses and no difference was observed between wearing coated eyewear and wearing no eyewear. The study concluded that fogging of lenses has a significant effect on visual detection and the use of anti-fog coating is relatively effective. However, in environments where prolonged fogging occurs water droplets form on anti-fog coated lenses which disrupts visual performance in a manner similar to the fog it is trying to prevent. It is recommended that anti-fog coating be considered when purchasing protective eyewear, and a bench test be developed to assess the coatings applied to eyewear.

Adult↗

PubMed2004

The N termini of Friend of GATA (FOG) proteins define a novel transcriptional repression motif and a superfamily of transcriptional repressors.

Members of the Friend of GATA (FOG) family of transcriptional co-factors are required for the development of both the cardiovascular and hematopoietic systems. FOG proteins physically interact with members of the GATA family of transcriptional activators and modulate their activity. We have previously shown that FOG-2 can bind to the N-terminal zinc finger of GATA4 and, via this interaction, repress GATA4-mediated transcriptional activation of various cardiac promoters. In this report we further characterize the domain of FOG-2 necessary for repression of GATA4 transcriptional activity. We show that FOG-2-mediated repression is not blocked by the histone deacetylase inhibitor tricostatin A, suggesting that FOG-2 repression of GATA4 occurs via a histone deacetylase independent mechanism. N-terminal deletion mutants of FOG-2 revealed that the first 12 amino acids of FOG-2 are necessary for FOG-2-mediated repression. Fusion of these 12 amino acids to the DNA binding domain of GAL4 demonstrated that this region is sufficient to mediate transcriptional repression even when recruited to a heterologous promoter. Single amino acid substitutions within this N-terminal domain of FOG-2 defined the critical amino acid sequence as RRKQxxPxxI. Interestingly, a search of the NCBI protein data base identified several other partially characterized zinc finger transcriptional repressors from various vertebrate species that contained this motif at their N terminus. Taken together, these observations define a novel transcriptional repression motif and a superfamily of zinc finger transcriptional repressors.

Amino Acid Motifs↗

PubMed1990

fog-1, a regulatory gene required for specification of spermatogenesis in the germ line of Caenorhabditis elegans.

In wild-type Caenorhabditis elegans, the XO male germ line makes only sperm and the XX hermaphrodite germ line makes sperm and then oocytes. In contrast, the germ line of either a male or a hermaphrodite carrying a mutation of the fog-1 (feminization of the germ line) locus is sexually transformed: cells that would normally make sperm differentiate as oocytes. However, the somatic tissues of fog-1 mutants remain unaffected. All fog-1 alleles identified confer the same phenotype. The fog-1 mutations appear to reduce fog-1 function, indicating that the wild-type fog-1 product is required for specification of a germ cell as a spermatocyte. Two lines of evidence indicate that a germ cell is determined for sex at about the same time that it enters meiosis. These include the fog-1 temperature sensitive period, which coincides in each sex with first entry into meiosis, and the phenotype of a fog-1; glp-1 double mutant. Experiments with double mutants show that fog-1 is epistatic to mutations in all other sex-determining genes tested. These results lead to the conclusion that fog-1 acts at the same level as the fem genes at the end of the sex determination pathway to specify germ cells as sperm.

Alleles↗

PubMed1999

Detection and quantification of changes in membrane-associated calcium in red spruce saplings exposed to acid fog.

Five-year-old red spruce saplings (Picea rubens Sarg.) were exposed to either (1) acid fog consisting of a mixture of H(2)SO(4) and HNO(3) adjusted to pH 2.5, (2) distilled-water fog at pH 5.6, or (3) no fog (dry control) for 3.5 hours per day, five times a week during the 1996 and 1997 growing seasons. The effect of fog on cell membrane-associated calcium (mCa) of leaf mesophyll cells was investigated with the fluorescence probe chlortetracycline (CTC). In both years, mean mCa concentrations were significantly less in needles exposed to acid fog than in needles exposed to distilled-water fog or in untreated needles. In 1997, acid-fog treatment resulted in 25 and 12% reductions in mCa in current-year needles, and 18 and 15% reductions in 1-year-old needles, compared with untreated needles and needles exposed to distilled-water fog, respectively, indicating that acid deposition induced calcium leaching from the membranes of photosynthetic mesophyll cells. Exposure to distilled-water fog also led to reductions in mCa in young needles, suggesting that water films on needle surfaces can induce losses by diffusion between the needle interior and surface. Consistent with the chamber studies, field data obtained from red spruce trees at two sites in Maine showed that low mCa concentrations in needles were associated with exposure to acid fog.

Journal Article↗

PubMed1998

Failure of megakaryopoiesis and arrested erythropoiesis in mice lacking the GATA-1 transcriptional cofactor FOG.

GATA transcription factors are required for the differentiation of diverse cell types in several species. Recent evidence suggests that their biologic activities may be modulated through interaction with multitype zinc finger proteins, such as Friend of GATA-1 (FOG) and U-shaped (Ush). In cell culture, FOG cooperates with the hematopoietic transcription factor GATA-1 to promote erythroid and megakaryocytic differentiation. We show here that mice lacking FOG die during mid-embryonic development with severe anemia. FOG-/- erythroid cells display a marked, but partial, blockage of maturation, reminiscent of GATA-1- erythroid precursors. In contrast to GATA-1 deficiency, however, megakaryocytes fail to develop in the absence of FOG. Although the FOG-/- erythroid phenotype supports the proposed role of FOG as a GATA-1 cofactor in vivo, the latter finding points to a pivotal, GATA-1-independent requirement for FOG in megakaryocyte development from the bipotential erythroid/megakaryocytic progenitor. We speculate that FOG and other FOG-like proteins serve as complex cofactors that act through both GATA-dependent and GATA-independent mechanisms.

Animals↗

PubMed1991

The effects of sequential exposure to acidic fog and ozone on pulmonary function in exercising subjects.

In Southern California coastal regions, morning fog is often acidified by the presence of nitric acid (HNO3). Peak exposure to ozone (O3) usually occurs in the afternoon and evening, after the fog has dissipated. To determine whether fog containing HNO3 might enhance pulmonary responses to O3, we studied a group of healthy, athletic subjects selected for lung function sensitivity to O3. On 3 separate days, the subjects exercised for 2 h in atmospheres containing HNO3 fog (0.5 mg/ml), H2O fog, or clean, filtered air. After a 1-h break, they exercised for an additional 3 h in an atmosphere containing 0.20 ppm O3. Surprisingly, the mean O3-induced decrements in FEV1 and FVC were smaller after exercise in each fog-containing atmosphere than they were after exercise in clean, filtered air. The mean (+/- SEM) O3-induced decrements in FEV1 were 26.4 +/- 5.3% after air, 17.1 +/- 3.7% after H2O fog, and 18.0 +/- 4.3% after HNO3 fog, and in FVC they were 19.9 +/- 4.7% after air, 13.6 +/- 2.8% after H2O fog, and 13.6 +/- 4.2% after HNO3 fog.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2000

FOG acts as a repressor of red blood cell development in Xenopus.

Members of the GATA family of zinc-finger transcription factors have critical roles in a variety of cell types. GATA-1, GATA-2 and GATA-3 are required for proliferation and differentiation of several hematopoietic lineages, whereas GATA-4, GATA-5 and GATA-6 activate cardiac and endoderm gene expression programs. Two GATA cofactors have recently been identified. Friend of GATA-1 (FOG-1) interacts with GATA-1 and is expressed principally in hematopoietic lineages, whereas FOG-2 is expressed predominantly in heart and brain. Although gene targeting experiments are consistent with an essential role for FOG-1 as an activator of GATA-1 function, reporter assays in transfected cells indicate that FOG-1 and FOG-2 can act as repressors. We have cloned a Xenopus laevis homologue of FOG that is structurally most similar to FOG-1, but is expressed predominantly in heart and brain, as well as the ventral blood island and adult spleen. Ectopic expression and explant assays demonstrate that FOG proteins can act as repressors in vivo, in part through interaction with the transcriptional co-repressor, C-terminal Binding Protein (CtBP). FOG may regulate the differentiation of red blood cells by modulating expression and activity of GATA-1 and GATA-2. We propose that the FOG proteins participate in the switch from progenitor proliferation to red blood cell maturation and differentiation.

Alcohol Oxidoreductases↗

PubMedDate not supplied

[Acid fog: hygiene and health observations correlated with an aspect of atmospheric pollution].

In the last years the interest about acid depositions has been shifted to heterogeneous phase reactions and, particularly, to occult precipitations (fog, mist, ecc.). It is very improbable that some kind of human health hazards could derive from acid rain exposure. Instead, the human exposure to acid fog could represent a possible respiratory vehicle for the assumption of acid pollutants as well as of many other pollutants. This last assertion can be supported by the following considerations: 1) Fog may represent an important chemical reactor that can modify the nature of pollutant material in the atmosphere (acidification and other events). 2) Fog is formed near the ground where pollution sources are located so that pollution is the heaviest. The fog water droplets coalesce around preexisting aerosol which is most highly concentrated near the ground (cities and industrial areas). Since fog water droplets contain muc less water than rain drops, they do not dilute the acidity as much as rain. 3) Finally, fog is partially inhalable. In certain areas of the world, wet deposition by fog can be important to the human health, even if the acqueous concentrations of fog droplets, the acidity per volume of air and the acid deposition rate are all important factors to consider. Particularly the pH of fog does not tell the whole story, but it represents a sufficient information about the severity of the atmospheric situation that can be correlated to seriousness of human risk.

Acid Rain↗

PubMed2005

Summer water use by California coastal prairie grasses: fog, drought, and community composition.

Plants in the Mediterranean climate region of California typically experience summer drought conditions, but correlations between zones of frequent coastal fog inundation and certain species' distributions suggest that water inputs from fog may influence species composition in coastal habitats. We sampled the stable H and O isotope ratios of water in non-photosynthetic plant tissue from a variety of perennial grass species and soil in four sites in northern California in order to determine the proportion of water deriving from winter rains and fog during the summer. The relationship between H and O stable isotopes from our sample sites fell to the right of the local meteoric water line (LMWL) during the summer drought, providing evidence that evaporation of water from the soil had taken place prior to the uptake of water by vegetation. We developed a novel method to infer the isotope values of water before it was subjected to evaporation in which we used experimental data to calculate the slope of the deltaH versus deltaO line versus the LMWL. After accounting for evaporation, we then used a two-source mixing model to evaluate plant usage of fog water. The model indicated that 28-66% of the water taken up by plants via roots during the summer drought came from fog rather than residual soil water from winter rain. Fog use decreased as distance from the coast increased, and there were significant differences among species in the use of fog. Rather than consistent differences in fog use by species whose distributions are limited to the coast versus those with broader distributions, species responded individualistically to summer fog. We conclude that fogwater inputs can mitigate the summer drought in coastal California for many species, likely giving an advantage to species that can use it over species that cannot.

California↗

PubMed2000

GATA-1- and FOG-dependent activation of megakaryocytic alpha IIB gene expression.

FOG is a multitype zinc finger protein that is essential for megakaryopoiesis, binds to the amino-terminal finger of GATA-1, and modulates the transcription of GATA-1 target genes. Presently investigated are effects of FOG and GATA-1 on the transcription of the megakaryocytic integrin gene, alpha IIb. In GATA-1-deficient FDCER cells (in the presence of endogenous FOG), ectopically expressed GATA-1 activated transcription 3-10-fold both from alpha IIb templates and the endogenous alpha IIb gene. The increased expression of FOG increased reporter construct transcription 30-fold overall. Unexpectedly, alphaIIb gene transcription also was stimulated efficiently upon the ectopic expression in of FOG per se. This occurred in the absence of any detectable expression of GATA-1 and was observed in multiple independent sublines for both the endogenous alpha IIb gene and transfected constructs yet proved to depend largely upon conserved GATA elements 457 and 55 base pairs upstream from the transcriptional start site. In 293 cells, FOG plus GATA-1 but not FOG alone only moderately stimulated alpha IIb transcription, and no direct interactions of FOG with the alpha IIb promoter were detectable. Thus, FOG acts in concert with GATA-1 to stimulate alpha IIb expression but also can act via a GATA-1-independent route, which is proposed to involve additional hematopoietic-restricted cofactors (possibly GATA-2).

Base Sequence↗

PubMed2005

Streptococcal protein FOG, a novel matrix adhesin interacting with collagen I in vivo.

Group G streptococcus (GGS) is a human pathogen of emerging clinical significance. It causes skin and soft tissue infections, occasionally resulting in life-threatening conditions such as sepsis and necrotizing fasciitis. We recently identified FOG, a novel surface protein of GGS with fibrinogen binding and immune evasion properties. Here we investigated the role of FOG in streptococcal primary adhesion to host tissue. A FOG-expressing clinical isolate adhered more efficiently to human skin biopsies ex vivo and to the murine dermis in vivo than a FOG-deficient strain. Scanning and transmission electron microscopy of skin specimens exhibited that this property was assigned to the ability of FOG to interact with collagen I, a major interstitial component of the dermis. Overlay experiments with human skin extracts and radiolabeled FOG followed by matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis identified both the alpha1- and alpha2-chains of collagen I as targets for FOG. Transmission electron microscopy of the molecular complexes revealed thread-like FOG molecules binding via their NH2 termini to distinct sites on collagen I monomers and fibrils. The results demonstrate that FOG is important for GGS adhesion in vivo, implying a pathogenic role for this surface protein.

Adhesins, Bacterial↗

PubMed2000

FOG-2, a novel F-box containing protein, associates with the GLD-1 RNA binding protein and directs male sex determination in the C. elegans hermaphrodite germline.

Male sex determination in the Caenorhabditis elegans hermaphrodite germline requires translational repression of tra-2 mRNA by the GLD-1 RNA binding protein. We cloned fog-2 by finding that its gene product physically interacts with GLD-1, forming a FOG-2/GLD-1/tra-2 3'untranslated region ternary complex. FOG-2 has an N-terminal F-box and a novel C-terminal domain called FTH. Canonical F-box proteins act as bridging components of the SCF ubiquitin ligase complex; the N-terminal F-box binds a Skp1 homolog, recruiting ubiquination machinery, while a C-terminal protein-protein interaction domain binds a specific substrate for degradation. However, since both fog-2 and gld-1 are necessary for spermatogenesis, FOG-2 cannot target GLD-1 for ubiquitin-mediated degradation. We propose that FOG-2 also acts as a bridge, bringing GLD-1 bound to tra-2 mRNA into a multiprotein translational repression complex, thus representing a novel function for an F-box protein. fog-2 is a member of a large, apparently rapidly evolving, C. elegans gene family that has expanded, in part, by local duplications; fog-2 related genes have not been found outside nematodes. fog-2 may have arisen during evolution of self-fertile hermaphroditism from an ancestral female/male species.

3' Untranslated Regions↗

PubMed2004

fog-2 and the evolution of self-fertile hermaphroditism in Caenorhabditis.

Somatic and germline sex determination pathways have diverged significantly in animals, making comparisons between taxa difficult. To overcome this difficulty, we compared the genes in the germline sex determination pathways of Caenorhabditis elegans and C. briggsae, two Caenorhabditis species with similar reproductive systems and sequenced genomes. We demonstrate that C. briggsae has orthologs of all known C. elegans sex determination genes with one exception: fog-2. Hermaphroditic nematodes are essentially females that produce sperm early in life, which they use for self fertilization. In C. elegans, this brief period of spermatogenesis requires FOG-2 and the RNA-binding protein GLD-1, which together repress translation of the tra-2 mRNA. FOG-2 is part of a large C. elegans FOG-2-related protein family defined by the presence of an F-box and Duf38/FOG-2 homogy domain. A fog-2-related gene family is also present in C. briggsae, however, the branch containing fog-2 appears to have arisen relatively recently in C. elegans, post-speciation. The C-terminus of FOG-2 is rapidly evolving, is required for GLD-1 interaction, and is likely critical for the role of FOG-2 in sex determination. In addition, C. briggsae gld-1 appears to play the opposite role in sex determination (promoting the female fate) while maintaining conserved roles in meiotic progression during oogenesis. Our data indicate that the regulation of the hermaphrodite germline sex determination pathway at the level of FOG-2/GLD-1/tra-2 mRNA is fundamentally different between C. elegans and C. briggsae, providing functional evidence in support of the independent evolution of self-fertile hermaphroditism. We speculate on the convergent evolution of hermaphroditism in Caenorhabditis based on the plasticity of the C. elegans germline sex determination cascade, in which multiple mutant paths yield self fertility.

Animals↗

PubMed1997

Effect of contralateral fog during refractive error assessment.

BACKGROUND: When assessing refractive error using static retinoscopy, it is conventional to fog the contralateral eye by approximately 2.00 D to prevent a blur-driven accommodative response stimulating consensual accommodation in the tested eye. However, the effect of higher amounts of contralateral fog (e.g., in a moderate-to-high uncorrected myopic individual) during refractive error assessment is unclear. METHODS: We assessed the refractive state in 16 visually normal myopic subjects while fogging the contralateral eye between zero and 6.00 D, in 1.00 D increments. Retinoscopy was simulated by shining a streak retinoscope light into the right eye, while simultaneously measuring the refractive state of this eye objectively. RESULTS: No significant change in mean refractive state was observed for up to 5.00 D of contralateral fog. But, 6.00 D of contralateral fog produced a significant mean increase in the myopic direction of 0.13 D. Also, in three subjects, a myopic shift of approximately 0.60 D was recorded after the introduction of 6.00 D of contralateral fog. Nevertheless, the magnitude of these largest shifts in refractive error are still smaller than the previously reported degree of repeatability of static retinoscopy. CONCLUSIONS: Since large amounts of contralateral fog produced only small and clinically insignificant changes in the refractive state, the practitioner merely needs to ensure that the nontested eye is indeed fogged. The magnitude of fog present will have only a minimal effect on the final result.

Adult↗