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At least 1,225 records · Page 68Linked to original sources
PubMed1984

Altered globin gene transcription pattern and the presence of a 7-8 kb alpha A globin gene transcript in avian erythroblastosis virus-transformed cells.

Immature chick erythroid cells transformed by avian erythroblastosis virus (AEV) display an altered pattern of globin gene transcription leading to the abortive phenotypic expression of such transcripts. Detectable adult globin gene-specific RNA sequences, confined exclusively to the nucleus, are uniquely of the alpha A type. The alpha A globin-specific sequences occur in transcripts 7-8 kb long from which the 5' contiguous alpha D gene product is absent, and also in fragments smaller than 9S globin mRNA. The implication of this observation for schemes of post-transcriptional regulation of gene expression and viral transformation are discussed.

Alpharetrovirus↗
PubMed1988

Characterization of a transcription factor involved in mother cell specific transcription of the yeast HO gene.

The yeast HO gene, which encodes an endonuclease involved in initiating mating type interconversion, is expressed in mother cells but not in daughters. It has been demonstrated that the SWI5 gene, which is an activator of HO expression, plays a critical role in this differential mother/daughter expression of HO. In this paper we describe the cloning and sequencing of the SWI5 gene. The predicted amino acid sequence derived from the cloned SWI5 gene shows homology with the repeated DNA-binding domains ('zinc fingers') of Xenopus transcription factor TFIIIA. A region of the HO promoter involved in the SWI5-dependent transcriptional activation of HO was identified by deletion analysis of the HO promoter in the chromosome, and by testing the ability of HO DNA fragments to activate transcription in the context of a heterologous promoter. The SWI5 gene product was overproduced in yeast from the GAL1-10 promoter, since the SWI5 protein is made at very low levels in wild-type strains, and protein extracts were used to demonstrate that the SWI5 protein binds in vitro to a segment of the HO promoter required for transcriptional activation in vivo.

Amino Acid Sequence↗
PubMed1994

Stoichiometry of mitochondrial transcripts and regulation of gene expression by mitochondrial transcription factor A.

The steady state concentration of cytochrome c oxidase subunit I mRNA and 12 S rRNA, respectively, measured by a quantitative reverse transcription/polymerase chain reaction method, was 4 and 15 molecules per molecule of mt DNA in rat liver and 2 and 9 molecules in rat muscle, respectively. These results imply that in the mitochondrial compartment, the molar concentration of all thirteen mRNAs by far exceeds the concentration of ribosomes, a situation fundamentally different from the cytosolic compartment. Following thyroid hormone treatment, both mitochondrial transcripts increased, in parallel with the mRNA encoding mitochondrial transcription factor A. We conclude that this transcription factor might be the rate limiting factor for mitochondrial transcription in vivo, at least under these conditions.

Animals↗
PubMed1997

Okadaic acid stimulates H ferritin transcription in HeLa cells by increasing the interaction between the p300 CO-activator molecule and the transcription factor Bbf.

The transcription of the human H ferritin gene is regulated by a transcription factor, called Bbf, which binds an enhancer element located in the -100/+1 region of the H promoter. To evaluate a possible role of Bbf phosphorylation on the promoter efficiency, we exposed HeLa cells to the phosphatase inhibitor okadaic acid (OA). The okadaic acid treatment increased about 4-fold the transcription driven by the -100/+1 region of the H promoter. However, the DNA binding activity of Bbf was not modified by OA, as assessed by EMSA. Immunoprecipitation experiments demonstrated that the OA-treatment stimulates and/or stabilizes the complex between Bbf and the nuclear protein p300, most probably by inducing the phosphorylation state of the complex. Bbf depends on the p300 molecule to trigger RNA polymerase II and thus transcription of the H ferritin gene.

Cyclic AMP Response Element-Binding Protein A↗
PubMed1993

Residues of the Bacillus subtilis phage phi 29 transcriptional activator required both to interact with RNA polymerase and to activate transcription.

Regulatory protein p4 from Bacillus subtilis phage phi 29 activates transcription from the viral late promoter, PA3, by stabilizing the binding of RNA polymerase to the DNA as a closed complex. Protein p4-induced DNA bending and direct contacts between p4 and RNA polymerase have been proposed to play a role in P(A3) activation. By site-directed mutagenesis at the carboxyl end of protein p4 we have identified residues that are critical both to interact with RNA polymerase and to activate transcription. Substitution of arginine 120 gives rise to a p4 derivative unable to activate transcription, that can bind to DNA and induce a normal DNA bending, but does not stimulate the binding of RNA polymerase to the promoter and cannot form complexes with RNA polymerase. Modification of the closely located residue leucine 117 had a similar but milder effect. The results obtained suggest that arginine 120 and leucine 117 form part of the activating domain of the protein, and show that direct contacts between protein p4 and RNA polymerase play a critical role in transcription activation. The p4-induced DNA bending is therefore necessary but not sufficient for the activation of the PA3 promoter.

Amino Acid Sequence↗
PubMed1994

Stress-induced transcriptional activation mediated by YAP1 and YAP2 genes that encode the Jun family of transcriptional activators in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae YAP2 gene encoding an AP-1-like transcriptional activator protein was cloned by selection for genes that confer pleiotropic drug resistance when present in high copy number. The novel YAP2 gene encodes a protein of 45827 daltons and is homologous in part to a known transcriptional activator protein encoded by YAP1/PDR4/SNQ3/PAR1. Homology was found only in both terminal regions. The N-terminal portion contains a region rich in basic amino acids, followed by a "leucine zipper" motif. Overexpression of YAP2 led to the induction of expression of an AP-1 recognition element (ARE)-dependent promoter. The yap1 disruptant has been shown to be sensitive to H2O2. In this study, we demonstrated that the yap1 disruptant is also unable to grow in medium containing 150 microM cadmium, whereas the yap2 disruptant exhibited no significant phenotypes. However, YAP2 in high copy number did suppress cadmium sensitivity, but not H2O2 sensitivity of the yap1 disruptant. YAP1 was able to mediate both cadmium- and H2O2-induced transcriptional activation of an ARE-dependent promoter. A high-copy-number plasmid bearing YAP2 mediated cadmium-induced transcriptional activation of this promoter. The inductions were prevented by the antioxidant N-acetyl-L-cysteine.

Acetylcysteine↗
PubMed2001

Gene transcription in hepatocytes during the acute phase of a systemic inflammation: from transcription factors to target genes.

During an acute, systemic inflammation, the liver is triggered by blood-borne pro-inflammatory cytokines such as Tumor Necrosis Factor alpha, Interleukin-1beta and Interleukin-6. The end result is an up- or down-regulated synthesis and/or activation of liver-enriched transcription factors that in turn regulate many target genes coding for resident or secreted acute phase proteins. In this review, various classifications of these acute phase proteins are presented. Major inflammation-driven changes in the synthesis and/or activity of the hepatic transcription factors are illustrated. Some of their up- or down-regulated target genes are used as paradigms of the various transcriptional mechanisms that take place on gene promoters during an acute, systemic inflammation. Finally, further specific features of inflammation-associated gene transcription in liver from acute phase onset to resolution are provided.

Acute-Phase Reaction↗
PubMed2006

cry1Aa lacks stability elements at its 5'-UTR but integrity of its transcription terminator is critical to prevent decay of its transcript.

We analyzed the influence of the 5' and 3' untranslated regions of the Bacillus thuringiensis cry1Aa on its mRNA stability. Although the cry1Aa gene has a stable transcript (8 min), its 5' UTR did not provide stability to the reporter gene uidA. Stability of cry1Aa could be increased to 40 min by addition of an SP82 stability element at the 5' UTR, suggesting that once the 5' and 3' ends were protected initiation of decay could be effectively blocked. We generated mutations in the transcription terminator and found that changes that reduced the stability of the stem, a larger loop, or elimination of the U-trail sharply decreased the half-life of the transcript. Therefore, unlike some stable bacterial transcripts, cry1Aa lacks special features at the end 5' to prevent decay, but its terminator is the main determinant of its stability.

5' Untranslated Regions↗
PubMed1992

Expression of human collagen type IV genes is regulated by transcriptional and post-transcriptional mechanisms.

The molecules of the basement membrane specific collagen type IV are heterotrimers consisting of two alpha 1(IV) and one alpha 2(IV) polypeptide chains. Comparison of the ratios of transcription by nuclear run-on analysis and mRNAs by RNAse protection assay indicates the involvement of transcriptional as well as post-transcriptional events in the control of overall collagen type IV expression. The relative ratios of transcription of the respective genes COL4A1 and COL4A2 remained near 2:1 in most cells, whereas the ratio of mRNA steady-state levels alpha 1(IV)/alpha 2(IV) varied from 0.3:1 to 1:1 and did not parallel the subunit structure of the protein. Nevertheless, secreted protein shows a 2:1 ratio of the subunit polypeptides. This indicates that post-translational processes during chain selection, aggregation and secretion finally determine the amount of secreted protein.

Cells, Cultured↗
PubMed1989

Transcriptional and post-transcriptional mechanisms are responsible for the increased expression of c-myc protooncogene in lymphocytes from patients with systemic lupus erythematosus.

Peripheral blood mononuclear cells (MNC) of patients with systemic lupus erythematosus (SLE) have increased expression of the c-myc protooncogene. The factors which are responsible for the accumulation of c-myc mRNA levels in SLE MNC, however, have not been determined. We have investigated the steady-state mRNA accumulation, nuclear transcription rate, rate of mRNA degradation as well as methylation status for the c-myc protooncogene in patients with SLE. Increased transcription rate of c-myc protooncogene and slow degradation rate of c-myc mRNA both appear to contribute to the accumulation of c-myc RNA in peripheral blood MNC of patients with SLE. Site-specific methylation of the human c-myc protooncogene in patients with SLE does not differ from that of normal controls. These findings provide evidence for both transcriptional and post-transcriptional alterations of c-myc protooncogene expression in human SLE.

Cell Nucleus↗
PubMed1989

A glycosylated liver-specific transcription factor stimulates transcription of the albumin gene.

HNF1 is a liver-specific transcription factor that plays the dominant role in determining the cell type-specific in vitro transcription of the albumin gene. Here we report the purification and preliminary characterization of HNF1. HNF1 appears to be heavily glycosylated since it is retained on a wheat germ agglutinin-agarose column and can be eluted from it with N-acetylglucosamine, a property not observed with other factors binding to the albumin promoter. Using in vitro transcription assays we demonstrate that purified HNF1 strongly stimulates albumin promoter activity in spleen nuclear extracts, which are devoid of this factor. Likewise, an artificial promoter consisting of two HNF1 recognition sites in front of a TATA motif is strongly activated by HNF1 in such extracts. In addition to stimulating transcription directly by binding to its cognate site, HNF1 may further enhance albumin promoter activity by interacting cooperatively with other trans-acting factors.

Albumins↗
PubMed1991

Transcriptional activation of CLN1, CLN2, and a putative new G1 cyclin (HCS26) by SWI4, a positive regulator of G1-specific transcription.

SWI4 of budding yeast codes for a component of a transcription factor (cell cycle box factor, or CCBF) necessary for G1-specific expression of HO. We show that SWI4 is essential for haploid cell viability at high temperature and in a/alpha cells at all temperatures: SWI4-deficient cells arrest as large unbudded cells. Eight high copy number plasmids were identified that allow swi4- strains to grow under nonpermissive conditions. Two carry G1 cyclin genes, CLN1 and CLN2; another carries HCS26, coding for a putative cyclin, a/alpha swi4- mutants exhibit 3- to 20-fold reductions in the levels of CLN1, CLN2, and HCS26 transcripts. The requirement of SWI4 for transcription appears to be direct: each gene contains sites similar to the CCBF-binding site; CCBF binds to the upstream region of HCS26. We propose that SWI4 participates in a positive feedback loop by which CLN1, CLN2, and possibly HCS26 promote their own transcription in G1.

Amino Acid Sequence↗
PubMed1991

A liver-enriched transcriptional activator protein, LAP, and a transcriptional inhibitory protein, LIP, are translated from the same mRNA.

LAP, a transcriptional activator, and LIP, a transcriptional repressor, are translated from a single mRNA species by using two AUGs within the same reading frame. These two proteins share the 145 C-terminal amino acids that contain the basic DNA-binding domain and the leucine zipper dimerization helix. Probably owing to its higher affinity for its DNA cognate sequences, LIP can attenuate the transcriptional stimulation by LAP in substoichiometric amounts. As revealed by transient transfection experiments, a moderate increase in the LAP/LIP ratio results in a significantly higher transcriptional activation of an appropriate target gene. The LAP/LIP ratio increases about 5-fold during terminal rat liver differentiation and is thus likely to modulate the activity of LAP in the intact animal.

Animals↗
PubMed1995

Developmental regulation of Fc epsilon RII/CD23 expression in B-lineage cells: evidence for transcriptional and post-transcriptional levels of control.

The present studies show that the expression of cell surface Fc epsilon RII/CD23, detected with the monoclonal anti-Fc epsilon RII/CD23 antibody B3B4 or by the binding of IgE, is not restricted to the stage of resting mature virgin B lymphocytes. Murine CD23 was detected as a cell surface protein on two sIgG+ B-cell lines. Moreover, we detected full-length transcripts for Fc epsilon RII/CD23 in several members of a panel murine B lymphoid lineage cell lines representative of all stages of murine B lymphocyte development. Our findings suggest that regulation of CD23 translation may differ between B-cell lines at various stages of differentiation. The detection of mRNA transcripts for Fc epsilon RII/CD23 was not restricted to transformed cell lines. Fc epsilon RII/CD23 transcripts were amplified by RT-PCR from peritoneal and splenic B lymphocyte subpopulations that were sorted by flow cytometry into populations that did not express surface Fc epsilon RII/CD23. Our findings suggest that Fc epsilon RII/CD23 transcription and translation are not necessarily restricted to the narrow developmental window of murine B lymphocyte differentiation as previously thought. Our findings imply that Fc epsilon RII/CD23 may be expressed at the protein level at various stages of murine B lymphocyte differentiation. Investigations into the expression patterns and potential mechanisms of regulation of Fc epsilon RII/CD23 could provide insight into the basis for the wide range of immunological functions that have been proposed for Fc epsilon RII/CD23.

Animals↗
PubMed1992

Review: transcriptional and post-transcriptional regulation of interleukin 1 gene expression.

Interleukin 1 alpha (IL-1 alpha) and beta (IL-1 beta) are proinflammatory cytokines that are encoded by distinct genes, but share most biological activities. During the past several years, intense investigation has focused on elucidating the molecular basis for the regulation of IL-1 alpha and beta gene expression. While the overall organization of both genes is conserved in mammals, the DNA sequence homology is surprisingly limited. This supports the growing body of evidence suggesting that each gene is regulated by distinct cis- and transacting elements. Most recently, novel regulatory DNA sequence elements and several nuclear regulatory proteins have been identified, which ultimately participate in the control of IL-1 beta gene transcription. In addition to transcriptional controls, the stability of IL-1 mRNA can be selectively regulated by various inducing stimuli and other cytokines. Taken together, these transcriptional and post-transcriptional regulatory mechanisms provide stringent, yet flexible, control over expression of the IL-1 alpha and beta genes.

Animals↗
PubMed1990

Membrane depolarization and calcium induce c-fos transcription via phosphorylation of transcription factor CREB.

The mechanism by which the calcium influx signal, triggered by membrane depolarization, is transduced to the nucleus to activate c-fos proto-oncogene transcription has been characterized. A calcium response element (CaRE) that is indistinguishable from a cAMP response element (CRE) mediates transcriptional inducibility by depolarization. Its cognate transcription factor CREB is the target for both calcium and cAMP signals. CREB is rapidly phosphorylated in response to depolarization or cAMP, at a site known to be important for the transcriptional activating function of this protein. The convergent effects of calcium and cAMP on CREB activation are mediated by distinct protein kinase signaling pathways. CREB and its binding site, the Ca/CRE, can thus function as a regulatory element that integrates both calcium and cAMP signals in the control of gene expression.

Adrenal Gland Neoplasms↗
PubMed2006

Actin in transcription and transcription regulation.

Recent research has provided convincing evidence that actin plays several important roles in gene transcription. First, actin can bind transcription factors and determine their subcellular localization. Second, actin is a component of chromatin remodeling complexes involved in transcriptional activation. Third, actin binds directly to the RNA polymerases I, II and III, and is required for their full transcriptional activity. Fourth, actin associates with nascent mRNPs and participates in the recruitment of histone modifiers to transcribed genes. We do not know yet whether these functions are general, or restricted to certain subsets of genes.

Actins↗
PubMed2005

Transcription factor XBP-1 is expressed during osteoblast differentiation and is transcriptionally regulated by parathyroid hormone (PTH).

X-box-binding protein 1 (XBP-1) is a basic-region leucine zipper protein in the cyclic AMP response element binding protein/activating transcription factor (CREB/ATF) family of transcription factors involved in different cell-differentiation processes. We have investigated the expression of XBP-1 in differentiating MC3T3-E1 osteoblastic cells. Cultures were treated with ascorbic acid (AA) and beta-glycerophosphate (BGP) to induce differentiation. Under these conditions, the basal transcription of xbp-1 increases at day 2 following induction, peaks at day 5 and decreases thereafter. This result showed that xbp-1 gene is differentially expressed during MC3T3-E1 cell differentiation. Detection of XBP-1 by immunofluorescence at days 0 (control culture without AA and BGP), 8 and 21 showed that the protein has a major cytoplasmic perinuclear location. In addition, xbp-1 is transcriptionally upregulated by parathyroid hormone within 2.5 h of treatment and decreases thereafter.

Animals↗