Search results for "messenger"
showing 10 items of 1493 documents
Role of hepatocyte nuclear factor 3γ in the expression of human CYP2C genes
2004
Hepatocyte nuclear factor 3 gamma (HNF-3 gamma) is an important transcription factor for the maintenance of specific liver functions. However, its relevance in the expression of human cytochrome P450 (CYP) genes has not yet been explored. Several HNF3 putative binding sites can be identified in human CYP2C 5'-flanking regions. Gene reporter experiments with proximal promoters revealed that HNF-3 gamma transactivated CYP2C8, CYP2C9, and CYP2C19 (25-, 4-, and 4-fold, respectively), but it did not transactivate CYP2C18. However, overexpression of HNF-3 gamma in hepatoma cells by means of a recombinant adenovirus induced CYP2C9, CYP2C18, and CYP2C19 mRNA (4.5-, 20-, and 50-fold, respectively) b…
The POT1 gene for yeast peroxisomal thiolase is subject to three different mechanisms of regulation
1992
The Saccharomyces cerevisiae POT1 gene is, as are other yeast peroxisomal protein genes, inducible by fatty acids and repressible by glucose. We have now found that it is also induced during the stationary phase of the culture. To investigate these three regulatory circuits, we have studied the mRNA levels of regulatory mutants as well as the changes in chromatin structure upon gene activation. We conclude that the regulation of transcriptional activity in glucose repression, oleate induction, and stationary phase induction follow different molecular mechanisms. We suggest that this multiplicity of regulatory mechanisms may represent a general rule for the yeast peroxisomal protein genes.
Impairing Otp homeodomain function in oral ectoderm cells affects skeletogenesis in sea urchin embryos
2003
AbstractIn the sea urchin embryo skeletogenesis is the result of a complex series of molecular and cellular events that coordinate the morphogenetic process. Past and recent evidence strongly indicate that skeletal initiation and growth are strictly dependent on signals emanating from the oral ectodermal wall. As previously suggested, Orthopedia (Otp), a homeodomain-containing transcription factor specifically expressed in a small subset of oral ectoderm cells, might be implicated in this signalling pathway. In this study, we utilize three different strategies to address the issue of whether Otp is an upstream regulator of sketelogenesis. We describe the effects of microinjection of Otp mor…
A differential role of CREB phosphorylation in cAMP-inducible gene expression in the rat pineal
2000
In the rat pineal gland cAMP mediates nocturnal induction of the enzyme arylalkylamine N-acetyltransferase (AA-NAT) as well as of transcription factors such as inducible cAMP early repressor (ICER), Fos-related antigen-2 (Fra-2) and JunB. Cyclic AMP stimulates the phosphorylation of the DNA binding protein cAMP response element binding protein (CREB). While cAMP-induced CREB phosphorylation appears to be a prerequisite for AA-NAT and ICER gene expression, it is not known whether CREB phosphorylation accounts for the full cAMP response of the two genes. Furthermore, the significance of CREB phosphorylation in cAMP-activated Fra-2 and JunB transcription is unknown. In the present in vitro stu…
Histamine Upregulates Gene Expression of Endothelial Nitric Oxide Synthase in Human Vascular Endothelial Cells
2003
Background— Histamine has a short-term, transient, stimulating effect on endothelial nitric oxide synthase (eNOS) activity; however, long-term effects on eNOS have not been described yet. In addition, the vascular effect of histamine seems to depend critically on eNOS functionality. Therefore, we studied the effects of histamine on eNOS gene expression and function. Methods and Results— In human umbilical vein endothelial cells (HUVECs) and HUVEC-derived EA.hy 926 cells, histamine upregulated eNOS mRNA (RNase protection assay) and protein (electron microscopic immunocytochemistry) expression. The upregulation of eNOS could be prevented by mepyramine, a selective antagonist at the H 1 recep…
Ionizing radiation-induced E-selectin gene expression and tumor cell adhesion is inhibited by lovastatin and all-trans retinoic acid
2004
E-selectin mediated tumor cell adhesion plays an important role in metastasis. Here we show that ionizing radiation (IR) induces E-selectin gene and protein expression in human endothelial cells at therapeutically relevant dose level. E-selectin expression is accompanied by an increase in the adhesion of human colon carcinoma cells to primary human umbilical vein endothelial cells (HUVEC). The HMG-CoA reductase inhibitor lovastatin impairs IR-stimulated E-selectin expression as analyzed at the level of the protein, mRNA and promoter. Inactivation of Rho GTPases either by use of Clostridium difficile toxin A or by co-expression of dominant-negative Rho blocked IR-induced E-selectin gene indu…
The Arabidopsis Copper Transporter COPT1 Functions in Root Elongation and Pollen Development
2004
Copper plays a dual role in aerobic organisms, as both an essential and a potentially toxic element. To ensure copper availability while avoiding its toxic effects, organisms have developed complex homeostatic networks to control copper uptake, distribution, and utilization. In eukaryotes, including yeasts and mammals, high affinity copper uptake is mediated by the Ctr family of copper transporters. This work is the first report on the physiological function of copper transport in Arabidopsis thaliana. We have studied the expression pattern of COPT1 in transgenic plants expressing a reporter gene under the control of the COPT1 promoter. The reporter gene is highly expressed in embryos, tric…
Expression of a reporter gene is reduced by a ribozyme in transgenic plants
1994
A chimeric gene encoding a ribozyme under the control of the cauliflower mosaic virus (CaMV) 35S promoter was introduced into transgenic tobacco plants. In vivo activity of this ribozyme, which was designed to cleave npt mRNA, was previously demonstrated by transient expression assays in plant protoplasts. The ribozyme gene was transferred into transgenic tobacco plants expressing an rbcS-npt chimeric gene as an indicator. Five double transformants out of sixteen exhibited a reduction in the amount of active NPT enzyme. To measure the amount of ribozyme produced, in the absence of its target, the ribozyme and target genes were separated by genetic segregation. The steady-state concentration…
Homeostasis in the Central Dogma of molecular biology: the importance of mRNA instability
2019
Cell survival requires the control of biomolecule concentration, i.e. biomolecules should approach homeostasis. With information-carrying macromolecules, the particular concentration variation ranges depend on each type: DNA is not buffered, but mRNA and protein concentrations are homeostatically controlled, which leads to the ribostasis and proteostasis concepts. In recent years, we have studied the particular features of mRNA ribostasis and proteostasis in the model organism S. cerevisiae. Here we extend this study by comparing published data from three other model organisms: E. coli, S. pombe and cultured human cells. We describe how mRNA ribostasis is less strict than proteostasis. A co…
A Trans-amplifying RNA Vaccine Strategy for Induction of Potent Protective Immunity
2019
Here, we present a potent RNA vaccine approach based on a novel bipartite vector system using trans-amplifying RNA (taRNA). The vector cassette encoding the vaccine antigen originates from an alphaviral self-amplifying RNA (saRNA), from which the replicase was deleted to form a transreplicon. Replicase activity is provided in trans by a second molecule, either by a standard saRNA or an optimized non-replicating mRNA (nrRNA). The latter delivered 10- to 100-fold higher transreplicon expression than the former. Moreover, expression driven by the nrRNA-encoded replicase in the taRNA system was as efficient as in a conventional monopartite saRNA system. We show that the superiority of nrRNA- ov…