Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.11 (AMPK)
 12,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two homologs of the gene encoding the adrenocortical 21-hydroxylase (21-OHase) are located within the S region of the mouse major histocompatibility complex. Only one of these homologs, however, encoded the full-length sequence of 21-OHase, directed the synthesis of 21-OHase RNA in the mouse adrenal gland, and was capable of restoring 21-OHase activity when transfected into 21-OHase-deficient Y1 adrenocortical tumor cells. Y1 cells transfected with the 21-OHase gene, when stimulated with ACTH, increased the number of 21-OHase transcripts up to 10-fold. The 21-OHase gene was not expressed when transfected into mouse fibroblast L cells, and was poorly expressed and poorly regulated by ACTH when transfected into a Y1 mutant harboring a defective cAMP-dependent protein kinase. Marked decreases in expression of the 21-OHase gene were noted when DNA constructs that contained fewer than 230 base pairs in the 5' flanking region of the gene were transfected into Y1 cells. These results indicate that the 21-OHase gene encodes information required for the tissue-specific expression and hormonal regulation of 21-OHase. The cAMP-dependent protein kinase is important for both aspects of gene expression. At most, 230 base pairs of 5' non-coding information are required for efficient expression of the 21-OHase gene in Y1 cells.
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PMID:Molecular analysis of 21-hydroxylase gene expression in mouse adrenal cells. 243 43

The steroid 21-hydroxylase (21-OH) gene is selectively expressed in the adrenal cortex and is transcriptionally regulated by ACTH. We examined the role of the 5'-flanking sequences of 21-OH in this regulated expression by analyzing their ability to direct the expression of a human growth hormone (hGH) reporter gene upon transfection into Y1 mouse adrenocortical tumor cells. The 330 bp of 5'-flanking sequences directed basal and hormonally-inducible expression of hGH in Y1 cells, but did not direct expression in I-10 mouse testicular Leydig cells. Both constitutive and hormonally-inducible expression required a functional cAMP-dependent protein kinase. These results indicate that the first 330 bp of 5'-flanking sequences of the 21-OH gene contain sufficient information for cell-specific and hormonally regulated expression, and that this expression requires the integrity of cAMP-dependent protein kinase. Markedly lower expression of hGH was seen when 156 bp of 5'-flanking sequences were placed in front of the reporter gene, suggesting that sequences between -330 and -156 are essential for expression. The addition of sequences from -330 to -150 to the p-156GH plasmid, in either the correct or the reverse orientation, restored promoter activity to approximately the level obtained with the 330 bp of 5'-flanking sequences. Moreover, the addition of sequences from -230 to -150 increased by 5-fold the expression of hGH driven by the heterologous thymidine kinase promoter. Based on these results, we conclude that an enhancer element is contained within the sequences from 230 to 150 bp upstream of the transcription initiation site.
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PMID:Regulation of 21-hydroxylase gene expression. 254 98

The mouse gene encoding adrenal steroid 11 beta-hydroxylase (11 beta-OHase) has been cloned and the nucleotide sequence of its 5' end has been determined. The coding regions sequenced are homologous (75%) to the sequence of bovine 11 beta-OHase cDNA. The 5'-flanking region of the 11 beta-OHase gene contains a potential cAMP response element (TGACGTGA) located 56 base pairs upstream of the transcription initiation site (position -56) and two motifs at positions -249 and -148 which are similar to an element postulated to be required for the expression of 21-hydroxylase. Transfection of mouse Y1 adrenocortical tumor cells and MA-10 testicular Leydig cells with plasmids containing the 11 beta-OHase promoter linked to a growth hormone reporter gene showed that the 11 beta-OHase promoter can direct cell-specific expression. Deletion analyses of the 5'-flanking region suggest that multiple sequence elements, one of which is located between positions -425 and -338 and a second between positions -338 and -123, interact to produce full levels of promoter activity. Mutant Y1 cells defective in cAMP-dependent protein kinase activity do not express growth hormone driven by the 11 beta-OHase promoter, indicating that expression of 11 beta-OHase in Y1 cells requires an intact cAMP second messenger system. Moreover, mutation of the putative cAMP response element at position -56 abolishes expression. These experiments thus present a useful system for the investigation of cis-acting elements involved in the transcriptional regulation of 11 beta-OHase.
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PMID:Structural and functional analysis of the promoter region of the gene encoding mouse steroid 11 beta-hydroxylase. 278 17

The steroid 21-hydroxylase (21-OHase) gene is selectively expressed at high levels in cells of the adrenal cortex and is transcriptionally regulated by corticotropin (ACTH). In this study, we examined the contribution of cis-acting nucleotide sequences to the regulated expression of the mouse 21-OHase gene. The 5'-flanking sequences of the mouse 21-OHase gene, extending 330 bp upstream from the transcription initiation site, were placed in front of the human growth hormone (hGH) reporter gene, and expression of the fusion gene was measured following transient transfection in Y1 mouse adrenocortical tumor cells. The 330 bp of 21-OHase flanking sequence directed both basal and ACTH-stimulated expression of hGH in Y1 adrenocortical cells but did not direct hGH expression in I-10 mouse testicular Leydig cells or in mouse fibroblast L cells. The 21-OHase/hGH fusion gene was poorly expressed in Y1 mutants defective in cAMP-dependent protein kinase activity. These results indicate that sequences necessary for adrenal cell-selective and ACTH-regulated expression of the 21-OHase gene reside within the first 330 bp of 5'-flanking DNA and that constitutive expression of the gene requires the integrity of cAMP-dependent protein kinase. The constitutive expression of hGH in Y1 cells was decreased dramatically (40-fold) when the 21-OHase flanking sequences in front of hGH were shortened to 156 bp from the transcription initiation site and was restored when the upstream sequences of the 21-OHase gene, from -330 to -150, were added back; the sequences from -330 to -150 were equally effective in either the correct or reverse orientation. From these observations, we conclude that an enhancer element is contained within the sequences from -330 to -150 bp upstream of the 21-OHase transcription initiation site.
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PMID:An enhancer element and a functional cyclic AMP-dependent protein kinase are required for expression of adrenocortical 21-hydroxylase. 284 6

The potent mitogen and tumor promoter, phorbol 12-myristate 13-acetate (PMA), has a primary action via activation of calcium-dependent protein kinase C. The treatment of monolayer cultures of human fetal adrenal neocortex (HFA) cells with PMA (50-250 nM) stimulated basal dehydroepiandrosterone sulfate (DS) secretion 2-3 fold. ACTH-treated HFA cells secreted amounts of DS and cortisol (F) 10-50 fold greater than basal secretions. PMA (250 nM) addition with ACTH to HFA cells decreased DS and F secretions at least 75% on days 2 and 3 of treatment. Treatment of HFA cells with 4 alpha-phorbol, which does not activate calcium-dependent protein kinase C, did not inhibit steroidogenesis. The attenuated rates of steroidogenesis after PMA treatment correlated with the decreased amounts of steroid 11 beta, 17 alpha- and 21-hydroxylase cholesterol side-chain cleavage steroid dehydrogenase and sulfotransferase activities. The decrease of steroid 17 alpha-hydroxylase activity correlated with the decreased amount of cytochrome P-450(17) alpha as determined after protein immunoblotting of NaDodSO4 cell lysates. After PMA treatment the ACTH-promoted increases of hydroxysteroid sulfotransferase and dehydrogenase activities of HFA cells were suppressed. PMA (50 nM) inhibited cAMP accumulation in ACTH-treated HFA cells, while 4 alpha-phorbol had no effect. Importantly, dibutyryl cAMP (0.2 mM) treatment of HFA cells did not reverse phorbol ester-promoted attenuation of steroidogenesis. We conclude that, in the presence of ACTH, phorbol ester chronically inhibits both cAMP synthesis and cAMP-dependent protein kinase action with resultant decreased steroidogenic enzyme synthesis and steroid production. This may be a consequence of activation, migration and a slow degradation of protein kinase C activity. These multifaceted actions of phorbol ester and associated protein kinase C activation may have critical effects on the ontogeny of fetal adrenal function.
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PMID:The action of phorbol ester on steroidogenesis in cultured human fetal adrenal cells. 303 Jul 21

Steroid 21-hydroxylase activity has been identified in many tissues, including liver. But it is possible that the enzyme found in the liver is different from adrenal 21-hydroxylase. In the adrenal cortex, steroid 21-hydroxylase activity is increased by corticotropin (ACTH); the effect of ACTH is mediated by cyclic AMP (cAMP), and presumably involves a cAMP-dependent protein kinase (PKA). It is not yet clear, however, how extra-adrenal steroid 21-hydroxylase activity is regulated. In the present study, we examined the effect of N6,2'-O-dibutyryl adenosine 3',5'-cyclic monophosphate (dbcAMP), forskolin, N-[2-(methylamino)ethyl]5-isoquinolinesulfonamide (H-8) and 12-O-tetradecanoylphorbol-13-acetate (TPA) on steroid 21-hydroxylase activity in primary cultures of rat hepatocytes to determine the nature of regulation of extra-adrenal steroid 21-hydroxylase activity. Steroid 21-hydroxylase activity in hepatocytes incubated with 10(-11) M dbcAMP for 24 h was 1.6 times higher than that in control hepatocytes untreated with dbcAMP. On the other hand, steroid 21-hydroxylase activity decreased by 20 and 50% when the cells were incubated with 10(-5) and 10(-3) M dbcAMP, respectively. The stimulatory effect of 10(-11) M dbcAMP was not blocked by 10(-5) M H-8 (PKA inhibitor), but the inhibitory effect of 10(-5) or 10(-3) M cAMP was. TPA did not alter the activity of steroid 21-hydroxylase. These findings indicate that the steroid 21-hydroxylase in rat liver is regulated by mechanisms different from those in the adrenal glands.
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PMID:Biphasic regulation by N6,2'-O-dibutyryl adenosine 3',5'-cyclic monophosphate (dbcAMP) of steroid 21-hydroxylase activity in rat hepatocytes. 818 Jan 19