Calcium ionophore A23187 induces expression of glucose-regulated genes and their heterologous fusion genes.

Resendez, E; Attenello, J W; Grafsky, A; Chang, Chung-Ming; Lee, Amy

doi:10.1128/mcb.5.6.1212

Cited by 148 publications

(102 citation statements)

References 25 publications

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“…In mammalian cells, expression of a set of glucoseregulated genes is induced by the calcium ionophore A21387 (20) . However, this induction reaches maximal levels rather slowly (after 3-4 h), is sustained, and is blocked by protein synthesis inhibitors, suggesting that induction ofthese genes may be a secondary effect of elevated Call levels .…”

Section: Discussionmentioning

confidence: 99%

Uncoupling of Chlamydomonas flagellar gene expression and outgrowth from flagellar excision by manipulation of Ca2+.

Cheshire

Keller

1991

The Journal of Cell Biology

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Abstract. Chlamydomonas cells respond to certain environmental stimuli by shedding their flagella. Flagellar loss induces a rapid, transient increase in expression of a specific set of genes encoding flagellar proteins, and assembly of a new flagellar pair. While flagellar gene expression and initiation of flagellar outgrowth are normally tightly coupled to flagellar excision, our results demonstrate that these processes can be uncoupled by manipulating Cal+ levels or calmodulin activity. In our experiments, wild-type cells were stimulated to excise their flagella using mechanical shearing, and at times after deflagellation, flagellar lengths were measured and flagellar mRNA abundance changes were determined by Sl nuclease protection analysis . When extracellular Caz+ was lowered by ad-ELLULAR responses to environmental cues often involve complex interactions between signal transduction pathways, gene regulatory circuits, and changes in cell morphology. In many cases, these responses are integrated through an intracellular messenger, such as Caz+ (5) . Although the role of Caz+ in signaling mechanisms, physiological responses, and cell movements has been well studied, relatively little is known about the role of Caz+ in regulating gene expression. The flagellar regeneration system of the unicellular green alga Chlamydomonas reinhardtii serves as a key model for studying the complexities of these types of interactions . A variety of extracellular treatments cause Chlamydomonas to excise their flagella (19a, 19, 21, 32) . When flagella are shed, expression ofa specific set offlagellar genes, including tubulin, is stimulated (1, 9), and cells begin to assemble a new pair of full-length flagella, using flagellar proteins translated from these newly synthesized mRNA templates, and preexisting flagellar proteins from a pool of unassembled precursors (21).The involvement of Caz+ in several aspects of flagellar regeneration has been demonstrated in previous studies . For example, some studies suggest that flagellar excision itself requires Caz+ (19a, 24 and references therein) . In addition, outgrowth of flagella after excision is dependent on Caz+ . Outgrowth is delayed or prevented by lowering the extracellular Caz+ concentration ([Caz+]e) to <10-6M, and occurs when the [Caz+], is restored (18,23) . In other studies, low dition of EGTA to cultures before excision, flagellar mRNA abundance changes and flagellar outgrowth were temporally uncoupled from flagellar excision. When extracellular Cal+ was lowered immediately after excision or when calmodulin activity was inhibited with W-7, flagellar outgrowth was uncoupled from flagellar excision and flagellar mRNA abundance changes . Whenever events in the process of flagellar regeneration were temporally uncoupled, the magnitude of the flagellar mRNA abundance change was reduced . These results suggest that flagellar gene expression may be regulated by multiple signals generated from these events, and implicate Caz+ as a factor in the mechanisms controlling flagellar rege...

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Section: Discussionmentioning

confidence: 99%

Uncoupling of Chlamydomonas flagellar gene expression and outgrowth from flagellar excision by manipulation of Ca2+.

Cheshire

Keller

1991

The Journal of Cell Biology

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“…The enhancer of the glucose-regulated protein 78 (grp78) gene was inserted upstream of the TATA box. The grp78 gene is transcribed constitutively in many different tissues and cell types (27) and is not regulated by REST. Upstream of the grp78 enhancer, two copies of the different NRSEs were inserted (Fig.…”

Section: Rest Repressed Transcription Of a Strong Mammalian Pro-motermentioning

confidence: 99%

Biological Activity and Modular Structure of RE-1-silencing Transcription Factor (REST), a Repressor of Neuronal Genes

Thiel¹,

Lietz²,

Cramer³

1998

Journal of Biological Chemistry

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The zinc finger protein RE-1-silencing transcription factor (REST) 1 is a transcriptional repressor that represses neuronal genes in nonneuronal tissues. Transfection experiments of neuroblastoma cells using a REST expression vector revealed that synapsin I promoter activity is controlled by REST. The biological activity of REST was further investigated using a battery of model promoters containing strong promoters/enhancers and REST binding sites. REST functioned as a transcriptional repressor when REST binding motifs derived from the genes encoding synapsin I, SCG10, ␣ 1 -glycine receptor, the ␤2-subunit of the neuronal nicotinic acetylcholine receptor, and the m4-subunit of the muscarinic acetylcholine receptor were present in the promoter region. No differences in the biological activity of these REST binding motifs tested were detected. Moreover, we found that REST functioned very effectively as a transcriptional repressor at a distance. Thus, REST represents a general transcriptional repressor that blocks transcription regardless of the location or orientation of its binding site relative to the enhancer and promoter. This biological activity could also be attributed to isolated domains of REST. Both repressor domains identified at the N and C termini of REST were transferable to a heterologous DNA binding domain and functioned from proximal and distal positions, similar to the REST protein. RE-1-silencing transcription factor (REST)1 , also known as neuron-restrictive silencer factor, functions as a transcriptional repressor of neuronal genes in nonneuronal tissues (1, 2). Target genes of REST are the genes encoding choline acetyltransferase, the type II sodium channel, SCG10, the m4 muscarinic acetylcholine receptor, and the adhesion proteins L1 and NgCAM (1-6). We have shown recently that the REST binding motif within the synapsin I promoter is responsible for restricting the expression of synapsin I to neuronal cells (7). Deletion of the REST binding site abolished neuron-specific expression of the reporter gene entirely, allowing constitutively acting elements of the promoter to direct expression in a nontissue specific manner.The REST binding motif termed the neural-restrictive silencer element (NRSE) was identified at various positions in those genes regulated by REST. NRSEs were found in the promoter region as shown for the synapsin I and the muscarinic acetylcholine receptor m4-subunit genes (7-9). In the SCG10 gene, an NRSE is located farther upstream at position Ϫ1472 to Ϫ1452 (10), whereas in the NgCAM gene, five NRSEs have been discovered within the first intron (3). Furthermore, genes encoding the ␣ 1 -glycine receptor and the ␤2-subunit of the neuronal nicotinic acetylcholine receptor contain NRSEs in the 5Ј-untranslated region downstream of the transcriptional start site (11,12). It has been proposed that REST switches its activity from repressing to activating transcription when REST binds to an NRSE located in the 5Ј-untranslated region or less than 50 base pairs upstream from the TATA bo...

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“…Plasmids for Northern blot hybridization of GRP78 and all plasmids used for transfection analyses of grp78 promoter activity were from Dr. Amy Lee (University of Southern California). Plasmid pI10, used for the majority of stable transfection studies, contains 1.25 kilobases of the rat grp78 promoter coupled to a chloramphenicol acetyltransferase (CAT) reporter gene (13). Other grp78 promoter constructs are described in Wooden et al (14) and the legend to Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Changes in GRP78 mRNA abundance seen with ethanol treatment could be due to increased grp78 gene transcription or altered GRP78 mRNA processing. To study the mechanism(s) underlying these actions of ethanol, we generated clonal isolates of NG108-15 cells stably transfected with a plasmid construct containing 1.25 kilobases of the hamster grp78 promoter coupled to a chloramphenicol acetyltransferase (CAT) reporter gene (13). Ethanol produced concentration-dependent increases in grp78 promoter activity in these stably transfected NG108-15 cells (Fig.…”

Section: Ethanol Increases Basal Grp78 Transcription and Potentiates mentioning

confidence: 99%

Interaction of Ethanol with Inducers of Glucose-regulated Stress Proteins

Hsieh

Wilke

Harris

et al. 1996

Journal of Biological Chemistry

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GRP78, a molecular chaperone expressed in the endoplasmic reticulum, is a "glucose-regulated protein" induced by stress responses that deplete glucose or intracisternal calcium or otherwise disrupt glycoprotein trafficking. Previously we showed that chronic ethanol exposure increases the expression of GRP78. To further understand the mechanism underlying ethanol regulation of GRP78 expression, we studied the interaction between ethanol and classical modulators of GRP78 expression in NG108-15 neuroblastoma ؋ glioma cells. We found that, in addition to increasing basal levels of GRP78 mRNA ("induction"), ethanol produced greater than additive increases in the induction of GRP78 mRNA by the "classical" GRP inducers A23187, brefeldin A, and thapsigargin ("potentiation"). Both the ethanol induction and potentiation responses modulated grp78 gene transcription as determined by stable transfection analyses with the rat grp78 promoter. Ethanol potentiated the action of all classical inducers of grp78 transcription that were studied. In contrast, co-treatment with the classical GRP inducers thapsigargin and tunicamycin produced only simple additive increases in grp78 promoter activity. Transient transfection studies with deletion mutants of the rat grp78 promoter showed that cis-acting promoter sequences required for ethanol induction differ from those mediating responses to classical GRP inducers. Furthermore, linker-scanning mutations of the grp78 promoter suggested that the ethanol potentiation response required a cis-acting promoter element different from those involved in induction by ethanol or classical inducing agents. While the ethanol induction response required 16 -24 h to be detectable, ethanol potentiation of thapsigargin occurred within 6 h. The potentiation response also decayed rapidly after ethanol removal. In addition, the protein kinase A inhibitor R p -cAMPS and protein phosphatase inhibitor okadaic acid both increased ethanol potentiation of thapsigargin while S p -cAMPS, an activator of protein kinase A, decreased ethanol potentiation. Taken together, our findings suggest two mechanisms by which ethanol regulates grp78 transcription, both differing from the action of classical GRP inducers such as thapsigargin. One mechanism (potentiation) involves a protein phosphorylation cascade and potentiates the action of classical GRP inducers. In contrast, GRP78 induction by ethanol involves promoter sequences and a mechanistic pathway separate from that of the ethanol potentiation response or classical GRP78 inducers. These studies show that ethanol produces a novel and complex regulation of grp78 transcription which could be of particular importance during neuronal exposure to GRP-inducing stressors as might occur with central nervous system injury.

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Calcium ionophore A23187 induces expression of glucose-regulated genes and their heterologous fusion genes.

Cited by 148 publications

References 25 publications

Uncoupling of Chlamydomonas flagellar gene expression and outgrowth from flagellar excision by manipulation of Ca2+.

Uncoupling of Chlamydomonas flagellar gene expression and outgrowth from flagellar excision by manipulation of Ca2+.

Biological Activity and Modular Structure of RE-1-silencing Transcription Factor (REST), a Repressor of Neuronal Genes

Interaction of Ethanol with Inducers of Glucose-regulated Stress Proteins

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