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G Duester

Publications and source records attributed to G Duester.

14 recordsLinked to original sources
PubMed1992

Retinoic acid activation and thyroid hormone repression of the human alcohol dehydrogenase gene ADH3.

Mammalian alcohol dehydrogenase (ADH) catalyzes the oxidation of retinol to retinaldehyde, the rate-limiting step in the synthesis of retinoic acid. There exists a family of ADH isozymes encoded by unique genes, and it is unclear which isozymes are most important for regulation of retinoic acid synthesis during differentiation or development. A region in the human ADH3 promoter from -328 to -272 base pairs was shown previously to function as a retinoic acid response element (RARE), prompting an hypothesis for a positive feedback mechanism controlling retinoic acid synthesis (Duester, G., Shean, M. L., McBride, M. S., and Stewart, M. J. (1991) Mol. Cell. Biol. 11, 1638-1646). The ADH3 RARE contains three direct AGGTCA repeats which constitute the critical nucleotides of RAREs present in other genes. We dissected the ADH3 RARE and determined that receptor binding as well as transactivation are dependent upon only the two downstream AGGTCA motifs separated by 5 base pairs, a structure noticed previously for a RARE in the promoter for the retinoic acid receptor beta (RAR beta) gene. ADH3 and RAR beta RAREs functioned similarly in transfection assays, suggesting that the feedback mechanisms controlling ADH3 and RAR beta utilize a common RARE. We also found that the normal functioning of the ADH3 RARE was abrogated by thyroid hormone receptor in the presence of thyroid hormone. A negative thyroid hormone response element in the human ADH3 promoter was found to colocalize with the RARE. Since ADH production in rat liver is known to be repressed by thyroid hormone, these findings suggest that human ADH production may also be subject to thyroid hormone repression and that the mechanism involves an interference with retinoic acid induction.

Alcohol Dehydrogenase↗
PubMed1992

Temporal expression of the human alcohol dehydrogenase gene family during liver development correlates with differential promoter activation by hepatocyte nuclear factor 1, CCAAT/enhancer-binding protein alpha, liver activator protein, and D-element-binding protein.

The human class I alcohol dehydrogenase (ADH) gene family consists of ADH1, ADH2, and ADH3, which are sequentially activated in early fetal, late fetal, and postnatal liver, respectively. Analysis of ADH promoters revealed differential activation by several factors previously shown to control liver transcription. In cotransfection assays, the ADH1 promoter, but not the ADH2 or ADH3 promoter, was shown to respond to hepatocyte nuclear factor 1 (HNF-1), which has previously been shown to regulate transcription in early liver development. The ADH2 promoter, but not the ADH1 or ADH3 promoter, was shown to respond to CCAAT/enhancer-binding protein alpha (C/EBP alpha), a transcription factor particularly active during late fetal liver and early postnatal liver development. The ADH1, ADH2, and ADH3 promoters all responded to the liver transcription factors liver activator protein (LAP) and D-element-binding protein (DBP), which are most active in postnatal liver. For all three promoters, the activation by LAP or DBP was higher than that seen by HNF-1 or C/EBP alpha, and a significant synergism between C/EBP alpha and LAP was noticed for the ADH2 and ADH3 promoters when both factors were simultaneously cotransfected. A hierarchy of ADH promoter responsiveness to C/EBP alpha and LAP homo- and heterodimers is suggested. In all three ADH genes, LAP bound to the same four sites previously reported for C/EBP alpha (i.e., -160, -120, -40, and -20 bp), but DBP bound strongly only to the site located at -40 bp relative to the transcriptional start. Mutational analysis of ADH2 indicated that the -40 bp element accounts for most of the promoter regulation by the bZIP factors analyzed. These studies suggest that HNF-1 and C/EBP alpha help establish ADH gene family transcription in fetal liver and that LAP and DBP help maintain high-level ADH gene family transcription in postnatal liver.

Alcohol Dehydrogenase↗
PubMed1991

The role of CCAAT/enhancer-binding protein in the differential transcriptional regulation of a family of human liver alcohol dehydrogenase genes.

The transcription factor CCAAT/enhancer-binding protein (C/EBP) was found to selectively trans-activate one member of the human class I alcohol dehydrogenase (ADH) gene family. A comparison of the promoters for the three human class I ADH genes ADH1, ADH2, and ADH3 indicated a very similar pattern of binding sites (sites A-F) for rat liver nuclear proteins located between -10 and -210 base pairs (bp). In all three promoters site A consisted of two binding sites for the transcription factor C/EBP closely flanking both sides of the TATA box, but C/EBP bound with much greater affinity to site A of ADH2. C/EBP also bound at two locations which coincide with site D (-120 bp) and site E (-160 bp) of all three promoters. Cotransfection studies of human hepatoma cells using ADH-cat fusions and a C/EBP expression plasmid indicated that the human ADH2 promoter responded well to C/EBP trans-activation whereas the human ADH1 and ADH3 promoters, which bind C/EBP weakly, responded poorly. Individual mutations in several ADH2 nuclear factor-binding sites allowed the identification of four functional C/EBP-binding sites, i.e. two in site A as well as one each in sites D and E. Also, the ADH2 TATA box was found to be dispensable for C/EBP induction. Compared to ADH2 and ADH3, site A in ADH1 contains four extra base pairs between the two C/EBP motifs, and deletion of these nucleotides increased the C/EBP responsiveness of ADH1 presumably by changing the spacing of the two C/EBP motifs. Thus, sequence divergence of human class I ADH gene family members has led to forms which vary in their responsiveness to C/EBP. We suggest that C/EBP contributes to liver-specific expression of the human class I ADH gene family by selectively inducing the ADH2 gene via a TATA-independent mechanism during liver development.

Alcohol Dehydrogenase↗
PubMed1991

A hypothetical mechanism for fetal alcohol syndrome involving ethanol inhibition of retinoic acid synthesis at the alcohol dehydrogenase step.

Ethanol acts as a teratogen causing brain, craniofacial, and limb abnormalities in those suffering from fetal alcohol syndrome. Normal embryonic development of the vertebrate nervous system and limbs has recently been shown to be governed by retinoic acid, the active form of vitamin A. Retinol dehydrogenase is an enzyme needed to convert vitamin A (retinol) to retinoic acid, a molecule that specifies embryonic pattern formation by controlling gene expression. Ethanol acts as a competitive inhibitor of the retinol dehydrogenase activity attributed to mammalian alcohol dehydrogenase (ADH), an enzyme that uses both retinol and ethanol as substrates. An hypothesis is presented in which many of the abnormalities observed in fetal alcohol syndrome may be caused by high levels of ethanol acting as a competitive inhibitor of ADH-catalyzed retinol oxidation in the embryo or fetus. This would presumably result in a reduction of retinoic acid synthesis in embryonic tissues such as the nervous system and limbs that require critical levels of this molecule to specify spatial patterns.

Alcohol Dehydrogenase↗
PubMed1991

Retinoic acid response element in the human alcohol dehydrogenase gene ADH3: implications for regulation of retinoic acid synthesis.

Retinoic acid regulation of one member of the human class I alcohol dehydrogenase (ADH) gene family was demonstrated, suggesting that the retinol dehydrogenase function of ADH may play a regulatory role in the biosynthetic pathway for retinoic acid. Promoter activity of human ADH3, but not ADH1 or ADH2, was shown to be activated by retinoic acid in transient transfection assays of Hep3B human hepatoma cells. Deletion mapping experiments identified a region in the ADH3 promoter located between -328 and -272 bp which confers retinoic acid activation. This region was also demonstrated to confer retinoic acid responsiveness on the ADH1 and ADH2 genes in heterologous promoter fusions. Within a 34-bp stretch, the ADH3 retinoic acid response element (RARE) contains two TGACC motifs and one TGAAC motif, both of which exist in RAREs controlling other genes. A block mutation of the TGACC sequence located at -289 to -285 bp eliminated the retinoic acid response. As assayed by gel shift DNA binding studies, the RARE region (-328 to -272 bp) of ADH3 bound the human retinoic acid receptor beta (RAR beta) and was competed for by DNA containing a RARE present in the gene encoding RAR beta. Since ADH catalyzes the conversion of retinol to retinal, which can be further converted to retinoic acid by aldehyde dehydrogenase, these results suggest that retinoic acid activation of ADH3 constitutes a positive feedback loop regulating retinoic acid synthesis.

Base Sequence↗
PubMed1990

Nucleotide sequence and expression of a cDNA encoding chick brain actin depolymerizing factor.

Chick brain actin depolymerizing factor (ADF) is a 19-kDa protein that severs actin filaments and binds actin monomers. We have obtained a cDNA encoding ADF by screening a chick embryo lambda gt11 cDNA library with both a rabbit anti-ADF antiserum and two oligonucleotide probes. Several non-full-length clones of 636 bases and one full-length clone of 1886 bases were isolated and sequenced. The full-length cDNA encodes a protein of 165 amino acids with a calculated molecular weight of 18,520. The deduced amino acid sequence shows 73% identity with the porcine brain actin binding protein cofilin. The coding region of the ADF cDNA has been placed in an expression vector, and the resulting protein shows immunoreactivity with an anti-ADF antiserum but not with an anti-cofilin antibody. The expressed ADF has been purified and has an actin depolymerizing activity identical with that of brain ADF. Like cofilin, ADF contains a sequence similar to the nuclear transport signal sequence of the SV40 large T antigen and a calcium/calmodulin-dependent protein kinase II phosphorylation consensus sequence. Northern blots of both embryonic chick brain and muscle RNA revealed two ADF mRNAs of length 2.1 and 0.9 kilobases. Southern blots suggest that the ADF gene is present in a single copy within the chicken genome. ADF contains regions of homology with other actin binding proteins including tropomyosin, gelsolin, and depactin.

Actin Depolymerizing Factors↗
PubMed1990

A hormone response element upstream from the human alcohol dehydrogenase gene ADH2 consists of three tandem glucocorticoid receptor binding sites.

The 5'-flanking region of the human gene encoding beta-alcohol dehydrogenase (ADH2) was shown by DNase I footprinting to contain three tandem binding sites for purified glucocorticoid receptor. The three binding sites lie very close together between nucleotide (nt) positions -245 and -171 with respect to the transcription start point. DNase I footprinting using a rat liver nuclear extract indicated a lack of protection of the glucocorticoid receptor binding sites, but protection of a sequence between nt -209 and -191 which partially overlaps the glucocorticoid receptor binding sites I and II. This site has homology with the known binding site for hepatocyte nuclear factor 1 (HNF1). ADH2 promoter DNA fragments containing various lengths of 5'-flanking sequences were fused upstream from the gene encoding chloramphenicol acetyltransferase (cat) and transfected into the HepG2 human hepatoma cell line. The resulting cat expression was subject to induction by dexamethasone in constructions containing ADH2 DNA between nt -272 and -171. This indicates that the glucocorticoid receptor binding sites identified by footprint analysis function as a glucocorticoid response element (GRE) in a liver cell line. Heterologous ADH-cat fusions, in which the ADH2-GRE was fused to the adenovirus major late promoter, exhibited glucocorticoid induction of cat expression in CV-1B cells when cotransfected with a glucocorticoid receptor expression vector. Glucocorticoid regulation in CV-1B was observed when either all three glucocorticoid receptor binding sites (sites 0, I, II) or the two distal sites (sites 0, I) were present. Overall, these results indicate that the ADH2 gene possesses a functional GRE which can potentially regulate expression transcriptionally.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Dehydrogenase↗
PubMed1990

Promoters for the human alcohol dehydrogenase genes ADH1, ADH2, and ADH3: interaction of CCAAT/enhancer-binding protein with elements flanking the ADH2 TATA box.

The human ADH1, ADH2, and ADH3 genes are closely related members of a gene family which are differentially expressed during liver development. To begin examining the mechanism of this tissue-specific and stage-specific expression, the 5'-flanking nucleotide (nt) sequences of the three genes were determined and the transcription start point (tsp) were identified. Sequences of all three genes indicated a high degree of homology (greater than 80% nt sequence identity) from the AUG translation start codon to about nt -780 relative to the tsp. Transient transfection assays of a set of plasmids containing various lengths of ADH 5'-flanking DNA fused to cat were performed in the HepG2 and Hep3B human hepatoma cell lines. The results indicated that the ADH2 promoter-proximal region was transcriptionally active in the absence of upstream sequences. To identify potential cis-acting elements in the ADH2 promoter-proximal region, a DNase I footprinting assay using a rat liver nuclear extract was used. Protection occurred in several locations including one, between nt -51 and -10, which shares homology with known binding sites for a previously identified rat-liver transcription factor called CCAAT/enhancer binding protein (C/EBP). Purified C/EBP was shown by footprint analysis to bind at two distinct sites in the ADH2 promoter located at nt -51 to -31 and -21 to -10. The TATA-box promoter element at nt -30 to -22 was not protected by C/EBP, but was partially protected by a factor in the rat liver nuclear extract. Thus, it is possible that the flanking C/EBP molecules may create a novel binding pocket for TFIID, the TATA-binding general transcription factor for RNA polymerase II. Alternatively, the C/EBP molecules may block access to the TATA box, and stimulate transcription of ADH2 by interacting with some component(s) other than TFIID.

Alcohol Dehydrogenase↗
PubMed1990

trans activation of human alcohol dehydrogenase gene expression in hepatoma cells by C/EBP molecules bound in a novel arrangement just 5' and 3' to the TATA box.

A promoter sequence between nucleotide -51 and nucleotide -10 in the human alcohol dehydrogenase gene ADH2 has been shown to bind the transcription factor CCAAT/enhancer-binding protein (C/EBP). A series of 5'-end deletions of the ADH2 promoter was cotransfected with a C/EBP expression plasmid in a human hepatoma cell line, and trans activation by C/EBP was seen when at least 171 base pairs of 5'-flanking DNA was present. Mutations in the ADH2 promoter indicate that the mechanism of C/EBP trans activation involves two binding sites, one located just upstream of the TATA box and one located in an unusual location between the TATA box and the transcription start point.

Alcohol Dehydrogenase↗
PubMed1986

Multiple mRNAs for human alcohol dehydrogenase (ADH): developmental and tissue specific differences.

Human class I alcohol dehydrogenase (ADH) genes show developmental and tissue specific differences in expression at the polypeptide level. In these studies ADH expression was investigated at the RNA level. Northern blot analysis of total and poly (A) RNA from adult liver using pADH12 probe demonstrated multiple RNA size classes of 2.6, 2.2, 1.9 and 1.6kb. In contrast, fetal liver, and fetal intestine contained only 2.6 and 1.6kb mRNA while fetal lung showed only 2.6kb mRNA. All of these tissues showed a relative reduction in the amount of ADH mRNA present when compared to adult liver. Immunoprecipitation of in vitro translation products of adult liver RNA by polyclonal ADH antibody revealed a single polypeptide of 40,000 daltons. This result points out the homogeneity of size of class I ADH polypeptides despite mRNA size diversity. Variation in length of the 3' untranslated region probably contributes to the multiple size classes of ADH mRNA observed.

Alcohol Dehydrogenase↗
PubMed1986

Intron-dependent evolution of the nucleotide-binding domains within alcohol dehydrogenase and related enzymes.

It has been suggested that the intron/exon structure of a gene corresponds to its evolutionary history. Accordingly, early in evolution DNA segments encoding short functional polypeptides may have been rearranged (exon-shuffling) to create full-length genes and RNA splicing may have been developed to remove intervening sequences (introns) in order to preserve translational reading frames. A conflicting viewpoint would be that introns were randomly inserted into previously uninterrupted genes after their initial evolutionary development. If so, the sites of introns would be unlikely to consistently reflect the domain structure of the protein. To address this question, the intron/exon structure of the gene encoding human alcohol dehydrogenase (ADH) was determined and compared to the gene structures for other ADHs and related proteins, all of which possess nucleotide-binding domains. Our results indicate that the introns in the nucleotide-binding domains of all the genes examined do indeed fall at positions which separate the short functional polypeptides (i.e. beta strands) which are believed to comprise this domain. We argue that our data is most easily explained by the hypothesis that introns were present in an ancestral nucleotide-binding domain which was later rearranged by exon-shuffling to form the various dehydrogenases and kinases which utilize such a domain.

Alcohol Dehydrogenase↗
PubMed1986

Molecular analysis of the human class I alcohol dehydrogenase gene family and nucleotide sequence of the gene encoding the beta subunit.

Human alcohol dehydrogenase (ADH) exists as a heterogeneous group of isozymes capable of oxidizing a wide variety of aliphatic and aromatic alcohols. The five distinct human ADH subunits, each encoded by a separate gene, are differentially expressed during development and are subject to tissue-specific regulation. To analyze the organization and regulation of human ADH genes we first isolated a cDNA clone (pADH12) encoding the 3' portion of the beta ADH gene. In the current study pADH12 was used to screen a human genomic library, and several overlapping and nonoverlapping clones were selected. Hybridization and partial nucleotide sequence analyses of the clones indicated that three full-length human ADH genes encoding the alpha, beta, and gamma subunits were isolated. Human genomic DNA hybridization results indicate that the alpha, beta, and gamma ADH genes form a closely related gene family and suggest that the other known human ADH genes (i.e. those encoding the pi and chi subunits) share a more distant evolutionary relationship. Nucleotide sequence analysis of the beta ADH gene reveals that the coding region is interrupted by eight introns and spans approximately 15 kilobases. A presumptive transcription initiation site for the beta ADH gene was located by S1 nuclease mapping at a position 70 base pairs upstream of the start codon. The 5' flanking region possesses a TATA box promoter element as well as two tandem DNA sequences which display homology to previously examined glucocorticoid-responsive elements.

Alcohol Dehydrogenase↗
PubMed1986

Androgen induction of alcohol dehydrogenase in mouse kidney. Studies with a cDNA probe confirmed by nucleotide sequence analysis.

A cDNA clone for the beta-chain of human alcohol dehydrogenase (ADH) was used to isolate several cross-hybridizing clones from a mouse liver cDNA library. Clones pADHm9 and a portion of pADHm12 were sequenced. pADHm9 coded for a sequence of 151 C-terminal amino acids and some untranslated sequences from the 3' end of its corresponding mRNA. This clone was identified as an Adh-1 cDNA clone. Consistent with the known expression of Adh-1, this gene was expressed constitutively in liver, whereas the Adh-3 gene product was found only in stomach, lung and reproductive tissues. Furthermore, the translated region of the cDNA shared 91% amino acid sequence homology with rat liver ADH. [32P]pADHm9 was used as a hybridization probe to study the mechanism of androgen induction of kidney ADH activity. Induction of A/J female mice by androgen resulted in a dramatic increase in the steady-state level of Adh-1 mRNA content which correlated with the level of enzyme induction. The size of the mRNA obtained from control or induced kidney and liver tissues was indistinguishable by Northern analysis. [32P]pADHm9 was also used to probe restriction fragments of genomic DNA obtained from several inbred mouse strains. The hybridization patterns, considered with the genetic evidence, suggested that pADHm9 recognized sequences which may be present as only a single copy in the genome. No restriction fragment length polymorphisms were observed among the several inbred mouse strains examined.

Alcohol Dehydrogenase↗