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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A stable transfection assay was used to test the mechanism by which embryonic globin gene transcription is stimulated in adult erythroid cells exposed to butyric acid and its analogs. To test the appropriate expression and inducibility of chicken globin genes in murine erythroleukemia (MEL) cells, an adult chicken beta-globin gene construct was stably transfected. The chicken beta-globin gene was found to be coregulated with the endogenous adult mouse alpha-globin gene following induction of erythroid differentiation of the transfected MEL cells by incubation with either 2% dimethyl sulfoxide (DMSO) or 1 mM sodium butyrate (NaB). In contrast, a stably transfected embryonic chicken beta-type globin gene, rho, was downregulated during DMSO-induced MEL cell differentiation. However, incubation with NaB, which induces MEL cell differentiation, or alpha-amino butyrate, which does not induce differentiation of MEL cells, resulted in markedly increased levels of transcription from the stably transfected rho gene. Analysis of histone modification showed that induction of rho gene expression was not correlated with increased bulk histone acetylation. A region of 5'-flanking sequence extending from -569 to -725 bp upstream of the rho gene cap site was found to be required for both downregulation of rho gene expression during DMSO-induced differentiation and upregulation by treatment with NaB or alpha-amino butyrate. These data are support for a novel mechanism by which butyrate compounds can alter cellular gene expression through specific DNA sequences. The results reported here are also evidence that 5'-flanking sequences are involved in the suppression of embryonic globin gene expression in terminally differentiated adult erythroid cells.
Mol Cell Biol 1991 Sep
PMID:5'-flanking sequences mediate butyrate stimulation of embryonic globin gene expression in adult erythroid cells. 187 47

Chimeric genes composed of the human cardiac actin promoter driving the Escherichia coli lacZ reporter gene were constructed, transfected, and stably integrated into genomes of P19 embryonal carcinoma cells. The transfected constructs were expressed actively in cardiac myocytes formed following dimethyl sulfoxide (DMSO)-induced cell differentiation but poorly in undifferentiated cultures and in cultures treated with retinoic acid to develop into derivatives of the neuroectoderm. A number of deletions of the promoter were constructed and tested. Three regions required for efficient expression in P19-derived cardiac muscle were identified, each containing sequences referred to as CArG boxes (CC[AT-rich]6GG). This analysis indicated that regulatory sequences important for expression in cardiac muscle were present upstream of the core promoter identified previously by transient assays in skeletal myoblasts. Expression of the cardiac actin promoter was enhanced 10-fold in undifferentiated P19 cells in the presence of the myoD protein. The promoter regions important for expression in P19-derived cardiocytes were similar to those important for myoD-induced enhancement, a result we interpret to be consistent with the idea that cardiac muscle might contain a myoD-like activity.
Mol Cell Biol 1991 Sep
PMID:Multiple CArG boxes in the human cardiac actin gene promoter required for expression in embryonic cardiac muscle cells developing in vitro from embryonal carcinoma cells. 187 51

The in vitro effects of aneuploidogens on taxol-purified microtubules from whole Drosophila melanogaster and mouse brain were studied by a spectrophotometric assay and electron microscopy. Colchicine, acetonitrile, propionitrile, acrylonitrile, dimethylsulfoxide (DMSO), griseofulvin, and cadmium chloride inhibit microtubule assembly, whereas methoxyethyl acetate (MEA) does not. Qualitatively similar results were observed with D. melanogaster and mouse brain microtubules. The in vitro results from D. melanogaster correlate well with previously published results from in vivo assays monitoring induced sex chromosome aneuploidy in that effective aneuploidogens are observed to affect microtubule assembly. The inclusion of taxol does not appear to qualitatively affect the assembly assays with the chemicals tested. In contrast with results from assembly assays, the tested aneuploidogens, including colchicine, do not promote disassembly to taxol-purified microtubules. It is possible that taxol has shifted the equilibrium and stabilized the formed microtubules to the extent that they are no longer sensitive to aneuploidogen-induced disassembly.
Environ Mol Mutagen 1990
PMID:Aneuploidy in Drosophila. III: Aneuploidogens inhibit in vitro assembly of taxol-purified Drosophila microtubules. 197 71

The goal of this study was to delineate the effects of dopamine antagonists on the regulation of preproenkephalin mRNA and opioid peptides in the rat brain. We have developed a method whereby both mRNA and peptides can be efficiently measured in the same tissue extract, thus reducing the effects of intraspecies variation, differences in dissection and the number of animals required for statistical significance. A sub-chronic dose of haloperidol (3 mg/kg given i.p. in 100 microliters DMSO daily for 5 days) produced a 1.8-fold increase (P less than 0.001) in striatal preproenkephalin mRNA levels when compared to animals injected with vehicle dimethyl sulfoxide (DMSO) employing the same schedule. Total opioid peptides as measured by a radioimmunoassay directed to the N-terminus of enkephalins and endorphins were elevated 1.6 fold (P less than 0.001) in the rat striatum. However in other brain regions examined no increases were observed either in preproenkephalin mRNA or the tissue levels of opioid peptides. Analysis of the opioid-like immunoreactive peptides by reverse-phase HPLC analysis showed no dramatic changes in the ratios of the various opioid peptides between haloperidol and vehicle injected animals. Naive animals showed no statistical differences in opioid peptide levels compared to the haloperidol treated animals. There was a statistically significant decrease (30%) in the opioid peptide content of the animals injected with vehicle daily for 5 days when compared with the animals merely sacrificed, or those given acute injections (either with haloperidol or vehicle) the day of sacrifice.(ABSTRACT TRUNCATED AT 250 WORDS)
Brain Res Mol Brain Res 1990 Aug
PMID:Regulation of both preproenkephalin mRNA and its derived opioids by haloperidol--a method for measurement of peptides and mRNA in the same tissue extract. 217 Aug 2

The expression of fumarate reductase and other enzymes of anaerobic respiration in Escherichia coli was studied as a function of the redox potential (Eh) in the medium. Redox potentials up to +300 mV allowed full expression of fumarate reductase (frd) genes. Higher values resulted in decreased expression. The relationship between Eh and expression of frd could be approximated by the Nernst equation, assuming a redox couple with a midpoint potential Eo' = +400 mV to 440 mV. At Eh values greater than +510 mV (generated anaerobically by hexacyanoferrate(III] the degree of repression was the same as that obtained by O2. Hexacyanoferrate(III) also caused decreased activities of dimethylsulphoxide (DMSO), nitrite and nitrate reductases. Since expression of these enzymes depends on FNR, the gene activator of anaerobic respiratory genes, it is suggested that the function of FNR is controlled by a redox couple of Eo' = +400 mV to 440 mV.
Mol Microbiol 1990 Feb
PMID:Effect of positive redox potentials (greater than +400 mV) on the expression of anaerobic respiratory enzymes in Escherichia coli. 218 48

To determine whether regulation of c-myc proteins occurs during the differentiation of murine erythroleukemia cells, we examined c-myc protein synthesis and accumulation throughout dimethyl sulfoxide (DMSO)- or hypoxanthine-induced differentiation. c-myc protein expression exhibited an overall biphasic reduction, with an initial concomitant decrease in c-myc RNA, protein synthesis, and protein accumulation early during the commitment phase. However, as the mRNA and protein levels recovered, c-myc protein synthesis levels dissociated from the levels of c-myc mRNA and protein accumulation. This dissociation appears to result from unusual translational and posttranslational regulation during differentiation. Translational enhancement was suggested by the observation that relatively high levels of c-myc proteins were synthesized from relatively moderate levels of c-myc RNA. This translational enhancement was not observed with c-myb. Under certain culture conditions, we also observed a change in the relative synthesis ratio of the two independently initiated c-myc proteins. Posttranslational regulation was evidenced by a dramatic postcommitment decrease in the accumulated c-myc protein levels despite relatively high levels of c-myc protein synthesis. This decrease corresponded with a twofold increase in the turnover of c-myc proteins. The consequence of this regulation was that the most substantial decrease in c-myc protein accumulation occurred during the postcommitment phase of differentiation. This result supports the hypothesis that the reduction in c-myc at relatively late times is most important for completion of murine erythroleukemia cell terminal differentiation.
Mol Cell Biol 1990 Aug
PMID:Enhanced translation and increased turnover of c-myc proteins occur during differentiation of murine erythroleukemia cells. 219 40

Primary cells from rabbit mammary gland cultured on floating collagen were transfected with various plasmids in different conditions. Conventional transfection methods using DEAE-dextran or calcium phosphate followed by an osmotic shock with dimethyl sulphoxide (DMSO), polyethylene glycol (PEG) or glycerol did not prevent lactogenic hormones to induce casein synthesis. On the contrary and unexpectedly, casein synthesis was markedly stimulated by transfection. This amplification was obtained as well with DMSO, PEG and glycerol alone or in the presence of DEAE-dextran, calcium phosphate or DNA. None of these compounds induced casein synthesis in the absence of prolactin. A shock by DMSO also amplified the accumulation of beta-casein mRNA in the presence of prolactin. These results show for the first time that primary cultured mammary cells can be efficiently transfected and still keep their capacity to respond to lactogenic hormones. They also indicate that the short osmotic shocks conventionally used in transfection have a potent long-term stimulatory effect on casein gene expression, which is mediated through an unknown mechanism.
Mol Cell Endocrinol 1990 Oct 01
PMID:Osmotic shock of cultured primary mammary cells amplifies the hormonal induction of casein gene expression. 229 39

Five polycyclic aromatic hydrocarbons (PAHs) of different carcinogenic activities were evaluated for their effects on DNA synthesis (3HTdR labeling index (L.I.] of rat and human mammary epithelial cells (MEC) and for their effects on chromosomes in MEC-mediated sister chromatid exchange (SCE) assays. When compared with DMSO-treated cells, exposures of rat MEC to the two most potent carcinogens (5 micrograms/ml for 24 hr), i.e., 7,12-dimethylbenz(a)anthracene (DMBA) and benzo(a)pyrene (B[a]P), resulted in a 45-62% reduction in the L.I. of rat MEC. Another carcinogen, 20-methylcholanthrene (MCA), produced a 35-48% reduction in L.I., while the noncarcinogenic PAHs, 1,2-benzanthracene (BA) and benzo(e)pyrene (B[e]P), showed no effect. Similarly, exposures of human MEC to DMBA and B[a]P resulted in a 50-90% depression in L.I. while BA was significantly less effective (30% reduction). When co-cultivated with Chinese hamster V-79 cells in the presence of PAH, both rat and human MEC can activate and release the active metabolites to induce SCE in V-79 cells. In the rat MEC-mediated assay for all 5 PAHs, the frequencies of SCE per chromosome in DMBA-, B[a]P-, MCA-, BA-, B[e]P-, and DMSO (solvent control)-treated groups were 6, 3, 1.4, 0.7, 0.4, and 0.3, respectively. DMBA was most effective in increasing SCE, while B[e]P was ineffective. In the human MEC-mediated assay, B[a]P was more effective than DMBA in inducing SCE, and the frequencies of SCE per chromosome were 4.5 and 3.6 in B[a]P- and DMBA-treated groups, respectively. Comparing depression of L.I., SCE, and in vivo carcinogenicity for the 5 PAHs, SCE mediated by rat MEC is better correlated with carcinogenicity in rat than L.I. depression.
Environ Mol Mutagen 1990
PMID:Genotoxic effects of five polycyclic aromatic hydrocarbons in human and rat mammary epithelial cells. 230 52

mRNA hybridizing to probes for glutathione S-transferase (GST) subunits 1 and 2 (probe pGSTr 155) and subunit 7 (probe pGSTr 7) has been measured by Northern blot analysis in adult rat hepatocytes both in conventional monoculture and in co-culture with epithelial cells. In addition, several media conditions were used, namely with and without fetal calf serum (FCS) and with and without nicotinamide or dimethyl sulfoxide (DMSO). In monoculture, mRNA coding for subunits 1 and 2 was extensively reduced in the presence of FCS. In the absence of FCS, after an initial decrease, an increase of subunits 1 and 2 mRNA was noticed on day 6. When nicotinamide or DMSO was added to the medium, the GST subunits 1 and 2 mRNA level increased during the culture period. In co-culture, an initial reduction in levels of mRNA encoding subunits 1 and 2 was less marked and the values measured increased with co-culture time. Nicotinamide tended to reduce these mRNA levels, whereas DMSO increased them. In contrast, in conventional culture, mRNA encoding subunit 7 was expressed de novo and this induction was prevented by DMSO but not by nicotinamide. Similar results were obtained with co-culture.
Mol Pharmacol 1990 Mar
PMID:Changes in expression of mRNA coding for glutathione S-transferase subunits 1-2 and 7 in cultured rat hepatocytes. 231 89

The effect of dimethylsulphoxide (DMSO) on microfilament organisation has been studied in the mouse oocyte after staining with (NBD)-phallacidin. The cortical actin meshwork was disrupted by exposure of oocytes to 1.5 M DMSO at 37 degrees C, and this disruption was associated with changes in the cell surface, especially microvilli length and distribution, as observed by scanning electron microscopy. The irregular distribution of actin filaments observed also appears to lead to an irregular expansion of the cell after DMSO removal. However, when exposure to DMSO was combined with cooling, the effects on the microfilament system were much reduced. The reversibility of DMSO action is considered and the potential implications of microfilament disruption on the viability and functions of the oocyte discussed.
Mol Reprod Dev 1990 Jul
PMID:Dimethylsulphoxide affects the organisation of microfilaments in the mouse oocyte. 237 76


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