scholarly journals Developmentally regulated interactions of liver nuclear factors with the rat phosphoenolpyruvate carboxykinase promoter.

1990 ◽  
Vol 10 (5) ◽  
pp. 2418-2422 ◽  
Author(s):  
M Trus ◽  
N Benvenisty ◽  
H Cohen ◽  
L Reshef
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Fetal Liver ◽  
Sequential Pattern ◽  
Late Development ◽  
Developmentally Regulated ◽  
Nuclear Factors

A sequential pattern of interactions of trans-acting factors in rat liver with the phosphoenolpyruvate carboxykinase promoter during late development was observed. A liver-enriched factor, possibly AF1, interacted with the promoter in fetal liver, whereas a factor with the characteristics of C/EBP bound the promoter after birth with the onset of the gene expression.

Developmentally regulated interactions of liver nuclear factors with the rat phosphoenolpyruvate carboxykinase promoter

1990 ◽  
Vol 10 (5) ◽  
pp. 2418-2422
Author(s):  
M Trus ◽  
N Benvenisty ◽  
H Cohen ◽  
L Reshef
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Fetal Liver ◽  
Sequential Pattern ◽  
Late Development ◽  
Developmentally Regulated ◽  
Nuclear Factors

A sequential pattern of interactions of trans-acting factors in rat liver with the phosphoenolpyruvate carboxykinase promoter during late development was observed. A liver-enriched factor, possibly AF1, interacted with the promoter in fetal liver, whereas a factor with the characteristics of C/EBP bound the promoter after birth with the onset of the gene expression.

scholarly journals Cyclic AMP-dependent protein kinase regulates transcription of the phosphoenolpyruvate carboxykinase gene but not binding of nuclear factors to the cyclic AMP regulatory element.

1990 ◽  
Vol 10 (7) ◽  
pp. 3357-3364 ◽  
Author(s):  
P G Quinn ◽  
D K Granner
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Nuclear Extract ◽  
In Vitro Transcription ◽  
Catalytic Subunit ◽  
Nuclear Factors ◽  
Dependent Protein

We have examined the binding of factors in rat liver nuclear extracts to the phosphoenolpyruvate carboxykinase (PEPCK) gene cyclic AMP (cAMP) response element (CRE) and other CREs and have isolated a rat liver CRE-binding protein (CREBP) cDNA. In addition, we have examined the influence of altering the phosphorylation state of nuclear factors on both CRE binding and in vitro transcription. Specific binding to the PEPCK CRE was measured in a mobility shift assay. CRE sequences of the PEPCK, somatostatin, and glycoprotein hormone alpha subunit genes competed equally for binding of rat liver nuclear factors to the PEPCK CRE, whereas mutant PEPCK CRE sequences did not compete for binding. Oligonucleotides complementary to rat pheochromocytoma CREBP (Gonzalez et al., Nature [London] 337:749-752, 1989) were used to prime rat liver and brain cDNA in the polymerase chain reaction. The predominant CREBP molecule obtained was identical to the rat pheochromocytoma CREBP except for a 14-amino-acid deletion in the N-terminal half that was also present in a human placental cDNA (Hoeffler et al., Science 242:1430-1433, 1988). The regulation of transcription by cAMP was examined by coincubation of rat liver nuclear extract with the purified catalytic subunit of cAMP-dependent protein kinase (protein kinase A). Although binding to the CRE was unaffected, in vitro transcription directed by the PEPCK promoter was stimulated by catalytic subunit, and this effect was blocked by protein kinase inhibitor peptide. In contrast, when nuclear extract was coincubated with phosphatase, there was substantial inhibition of in vitro transcription directed by the PEPCK promoter, but there was no effect on binding to the CRE. The major effects of catalytic subunit were exerted through the CRE, but residual stimulation was evident in promoter fragments containing only the TATA element. These data suggest that factors are bound to the CRE at constitutively high levels and that their capacity for transcriptional activation is regulated by phosphorylation.

trans activation of rat phosphoenolpyruvate carboxykinase (GTP) gene expression by micro-coinjection of rat liver mRNA in Xenopus laevis oocytes

1989 ◽  
Vol 9 (11) ◽  
pp. 5244-5247
Author(s):  
N Benvenisty ◽  
T Shoshani ◽  
Y Farkash ◽  
H Soreq ◽  
L Reshef
Keyword(s):  
Gene Expression ◽  
Xenopus Laevis ◽  
Reporter Gene ◽  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Xenopus Laevis Oocytes ◽  
Activation Process ◽  
Tissue Specific ◽  
Chimeric Construct

To study the liver-specific trans activation of the rat phosphoenolpyruvate carboxykinase (PEPCK) gene, the PEPCK promoter was linked to a reporter gene and was microinjected into Xenopus laevis oocytes alone or in conjunction with rat liver poly(A)+ RNA. The rat liver mRNA markedly enhanced the expression of the PEPCK-chimeric construct. This effect appeared to be sequence specific, as it was dependent on the presence of the intact promoter. Moreover, the RNA effect was limited to mRNA preparations from PEPCK-expressing tissues only. Finally, microinjection of size-fractionated liver mRNA revealed that the trans-acting factor(s) is encoded by RNA of 1,600 to 2,000 nucleotides, providing a direct bioassay for the gene(s) involved in this tissue-specific trans-activation process.

Cyclic AMP-dependent protein kinase regulates transcription of the phosphoenolpyruvate carboxykinase gene but not binding of nuclear factors to the cyclic AMP regulatory element

1990 ◽  
Vol 10 (7) ◽  
pp. 3357-3364
Author(s):  
P G Quinn ◽  
D K Granner
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Nuclear Extract ◽  
In Vitro Transcription ◽  
Catalytic Subunit ◽  
Nuclear Factors ◽  
Dependent Protein

We have examined the binding of factors in rat liver nuclear extracts to the phosphoenolpyruvate carboxykinase (PEPCK) gene cyclic AMP (cAMP) response element (CRE) and other CREs and have isolated a rat liver CRE-binding protein (CREBP) cDNA. In addition, we have examined the influence of altering the phosphorylation state of nuclear factors on both CRE binding and in vitro transcription. Specific binding to the PEPCK CRE was measured in a mobility shift assay. CRE sequences of the PEPCK, somatostatin, and glycoprotein hormone alpha subunit genes competed equally for binding of rat liver nuclear factors to the PEPCK CRE, whereas mutant PEPCK CRE sequences did not compete for binding. Oligonucleotides complementary to rat pheochromocytoma CREBP (Gonzalez et al., Nature [London] 337:749-752, 1989) were used to prime rat liver and brain cDNA in the polymerase chain reaction. The predominant CREBP molecule obtained was identical to the rat pheochromocytoma CREBP except for a 14-amino-acid deletion in the N-terminal half that was also present in a human placental cDNA (Hoeffler et al., Science 242:1430-1433, 1988). The regulation of transcription by cAMP was examined by coincubation of rat liver nuclear extract with the purified catalytic subunit of cAMP-dependent protein kinase (protein kinase A). Although binding to the CRE was unaffected, in vitro transcription directed by the PEPCK promoter was stimulated by catalytic subunit, and this effect was blocked by protein kinase inhibitor peptide. In contrast, when nuclear extract was coincubated with phosphatase, there was substantial inhibition of in vitro transcription directed by the PEPCK promoter, but there was no effect on binding to the CRE. The major effects of catalytic subunit were exerted through the CRE, but residual stimulation was evident in promoter fragments containing only the TATA element. These data suggest that factors are bound to the CRE at constitutively high levels and that their capacity for transcriptional activation is regulated by phosphorylation.

scholarly journals trans activation of rat phosphoenolpyruvate carboxykinase (GTP) gene expression by micro-coinjection of rat liver mRNA in Xenopus laevis oocytes.

1989 ◽  
Vol 9 (11) ◽  
pp. 5244-5247 ◽  
Author(s):  
N Benvenisty ◽  
T Shoshani ◽  
Y Farkash ◽  
H Soreq ◽  
L Reshef
Keyword(s):  
Gene Expression ◽  
Xenopus Laevis ◽  
Reporter Gene ◽  
Rat Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Xenopus Laevis Oocytes ◽  
Activation Process ◽  
Tissue Specific ◽  
Chimeric Construct

To study the liver-specific trans activation of the rat phosphoenolpyruvate carboxykinase (PEPCK) gene, the PEPCK promoter was linked to a reporter gene and was microinjected into Xenopus laevis oocytes alone or in conjunction with rat liver poly(A)+ RNA. The rat liver mRNA markedly enhanced the expression of the PEPCK-chimeric construct. This effect appeared to be sequence specific, as it was dependent on the presence of the intact promoter. Moreover, the RNA effect was limited to mRNA preparations from PEPCK-expressing tissues only. Finally, microinjection of size-fractionated liver mRNA revealed that the trans-acting factor(s) is encoded by RNA of 1,600 to 2,000 nucleotides, providing a direct bioassay for the gene(s) involved in this tissue-specific trans-activation process.

Effects of Steroids on Fetal Rat Liver

1969 ◽  
Vol 27 ◽  
pp. 350-351
Author(s):  
F. G. Zaki
Keyword(s):  
Liver Injury ◽  
Rat Liver ◽  
Fetal Liver ◽  
Dosage Level ◽  
Maternal Plasma ◽  
Methyl Prednisolone ◽  
Fetal Rat ◽  
Toxic Agents ◽  
Fetal Rat Liver ◽  
Neonatal Liver

Fetal and neonatal liver injury induced by agents circulating in maternal plasma, even though well recognized, its morphological manifestations are not yet established. As part of our studies of fetal and neonatal liver injury induced by maternal nutritional disorders, metabolic impairment and toxic agents, the effects of two anti-inflammatory steroids have been recently inves tigated.Triamcinolone and methyl prednisolone were injected each in a group of rats during pregnancy at a-dosage level of 2 mgm three times a week. Fetal liver was studied at 18 days of gestation. Litter size and weight markedly decreased than those of control rats. Stillbirths and resorption were of higher incidence in the triamcinolone group than in those given the prednisolone.

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