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PubMed1992

Cooperative transcription activation between Ad1, a CRE-like element, and other elements in the CYP11B gene promoter.

We previously reported the presence of six different cis-acting elements (Ad1 to Ad6) in the promoter region of the bovine CYP11B gene. Although the Ad1 site (TGACGTGA) was similar to a palindromic CRE (TGACGTCA), two other upstream sequences, Ad3 and Ad4, were identified as the cAMP response sequences of the gene. We analyzed the functional relationship between the Ad1 site and the upstream elements. Mutation analyses of the Ad1 site indicated that the 5' half of the site (TGACG) was important for the transcription of the gene in vitro. In Y-1 cells, a plasmid with a mutated Ad1 showed no response to cAMP. The effect of the mutation at the Ad1 site on the cAMP response was almost the same as that of the deletion of Ad3 and Ad4, although the role of each element seemed to be different. These results indicated that both the Ad1 site and the upstream elements, Ad3 and Ad4, were necessary for the full response to cAMP of the CYP11B gene. When the Ad1 site in the promoter region was replaced with a palindromic CRE, elevated transcription activity was detected both in vitro and in vivo. Two kinds of CREBs (43 and 47 kDa) purified from a HeLa cell nuclear extract bound to the Ad1 site. The binding of the palindromic CRE to the nuclear factor(s) was stronger than that of Ad1.

Animals↗

PubMed1997

P element domestication: a stationary truncated P element may encode a 66-kDa repressor-like protein in the Drosophila montium species subgroup.

Functional P transposable elements can be separated into two distinct classes: mobile elements, which present the canonical structure, with transposase and repressor functions, and immobile P sequences truncated in 5' and 3' by loss of the terminal inverted repeats and exon 3, which retain only the repressor function. This second class was first described in some species of the Drosophila obscura group. Here, we describe a new truncated immobile P sequence cloned from one species of the Drosophila montium subgroup (D. tsacasi) that produces a polyadenylated RNA with a coding capacity for a 66-kDa "repressor-like" protein. The results from a number of different comparisons between P-homologous sequences concerning both coding and noncoding regions strongly suggest that the obscura and montium immobile P sequences as well as the T-type P subfamily derive from the same ancestral mobile P element family. Study of the flanking regions of these immobile P sequences shows that the two immobilizations were produced by two independent events. Our results provide evidence that the molecular domestication of a transposable element family may recur in a species lineage.

Amino Acid Sequence↗

PubMed1990

Localization of sequences required in cis for yeast Ty1 element transposition near the long terminal repeats: analysis of mini-Ty1 elements.

In order to identify and characterize sequences within Ty1 elements which are required in cis for transposition, a series of mini-Ty1 plasmids were constructed and tested for transposition. Mini-Ty1s are deletion mutants of the Ty1-H3 element; Ty1 gene products required for transposition are supplied in trans from a helper Ty1 which has intact open reading frames but lacks a 3' long terminal repeat (LTR) and therefore cannot transpose itself. Up to 5 kilobase pairs of internal sequences of the 6-kilobase-pair-long Ty1 element can be deleted without a significant effect on transposition. The smallest mini-Ty1 element capable of transposition contains the 3' LTR and the transcribed portion of the 5' LTR, 285 base pairs (bp) of internal sequence 3' to the 5' LTR, and 23 bp of internal sequence 5' to the 3' LTR. We conclude that Ty1-encoded proteins can act in trans and that cis-acting sequences in Ty1-H3 are all within or near the LTRs. Further deletion of the 285-bp internal sequence adjacent to the 5' LTR significantly reduced transposition frequency, and the mini-Ty1 RNA produced failed to be packaged into the viruslike particles efficiently. Surprisingly, several nonhomologous cellular mRNAs were also associated with viruslike particles.

Base Sequence↗

PubMed1996

The Drosophila P-element KP repressor protein dimerizes and interacts with multiple sites on P-element DNA.

Drosophila P elements are mobile DNA elements that encode an 87-kDa transposase enzyme and transpositional repressor proteins. One of these repressor proteins is the 207-amino-acid KP protein which is encoded by a naturally occurring P element with an internal deletion. To study the molecular mechanisms by which KP represses transposition, the protein was expressed, purified, and characterized. We show that the KP protein binds to multiple sites on the ends of P-element DNA, unlike the full-length transposase protein. These sites include the high-affinity transposase binding site, an 11-bp transpositional enhancer, and, at the highest concentrations tested, the terminal 31-hp inverted repeats. The DNA binding domain was localized to the N-terminal 98 amino acids and contains a CCHC sequence, a potential metal binding motif. We also demonstrate that the KP repressor protein can dimerize and contains two protein-protein interaction regions and that this dimerization is essential for high-affinity DNA binding.

Amino Acid Sequence↗

PubMed2007

Conserved cis-acting elements upstream of genes composing the chitinolytic system of streptomycetes are DasR-responsive elements.

For soil-dwelling bacteria that usually live in a carbon-rich and nitrogen-poor environment, the ability to utilize chitin - the second most abundant polysaccharide on earth - is a decisive evolving advantage as it is a source for both elements. Streptomycetes are high-GC Gram-positive soil bacteria that are equipped with a broad arsenal of chitinase-degrading genes. These genes are induced when the streptomycetes sense the presence of chitooligosaccharides. Their expression is repressed as soon as more readily assimilated carbon sources become available. This includes for example glucose or N-acetylglucosamine, the monomer subunit of chitin. Historically, the first cis-acting elements involved in carbon regulation in streptomycetes were found more than a decade ago upstream of chitinase genes, but the transcriptional regulator had so far remained undiscovered. In this work, we show that these cis-acting elements consist of inverted repeats with multiple occurrences and are bound by the HutC/GntR type regulator DasR. We have therefore designated these sites as DasR-responsive elements (dre). DasR, which is also the repressor of the genes for the N-acetylglucosamine-specific phosphotransferase transport system, should therefore play a critical role in sensing the balance between the monomeric and polymeric forms of N-acetylglucosamine.

Bacterial Proteins↗

PubMed2001

The Tol2 transposable element of the medaka fish: an active DNA-based element naturally occurring in a vertebrate genome.

Several DNA-based transposable elements are known to be present in vertebrate genomes, but few of them have been demonstrated to be active. The Tol2 element of the medaka fish is one such element and, therefore, is potentially useful for developing a gene tagging system and other molecular biological tools applicable to vertebrates. Towards this goal, analyses of the element at the molecular, cellular and population levels are in progress. Results so far obtained are described here.

Animals↗

PubMed2005

Age-related changes of elements in renal arteries of Thai and Japanese and the relationships among elements.

To examine whether there were differences between races in regard to age-related changes of elements and the relationships among elements in the arteries, the authors investigated both the renal arteries of Thai and Japanese. The Thai subjects consisted of 27 men and 11 women, ranging in age from 27 to 88 yr, whereas the Japanese subjects consisted of 19 men and 26 women, ranging in age from 61 to 99 yr. After the ordinary dissections at Chiang Mai University and Nara Medical University were completed, the bilateral renal arteries were resected and the element contents were determined by inductively coupled plasma-atomic emission spectrometry. In the Thai, a slight accumulation of calcium and phosphorus occurred in the fifties, but thereafter hardly increased. In contrast, in the Japanese, an accumulation of calcium and phosphorus began to occur in the seventies and increased markedly in the eighties. The result revealed that a higher accumulation of calcium and phosphorus occurred in the renal arteries of the Japanese in old age compared with those of the Thai. Regarding the relationships among elements, extremely or very significant direct correlations were found among the contents of calcium, phosphorus, magnesium, and sodium in both the renal arteries of the Thai and Japanese, except for magnesium and sodium contents in the renal arteries of the Thai.

Adult↗

PubMed2003

Age-related changes of elements in human thoracic ducts and azygos veins and relationships among elements.

To elucidate compositional changes of the thoracic duct with aging, the authors investigated age-related changes of elements in the thoracic ducts in comparison with the azygos veins. The subjects consisted of 22 men and 1 woman, ranging in age from 65 to 95 yr. After ordinary dissection, the thoracic ducts and azygos veins were resected from the subjects and element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that calcium appeared to increase in the thoracic duct with aging, but the other elements, such as phosphorus, sulfur, magnesium, iron, zinc, and sodium, did not change significantly with aging. In the azygos vein, both calcium and sulfur increased significantly with aging. Regarding the relationship among elements, extremely significant direct correlations were found among calcium, phosphorus, sulfur, and magnesium in the thoracic ducts, except for phosphorus and magnesium contents with a very significant direct correlation. In the azygos veins, significant direct correlations were found between calcium and sulfur contents and between sulfur and magnesium contents. However, no significant correlations were found among calcium, phosphorus, and magnesium in the azygos veins. These results revealed that with regard to the relationship among calcium, phosphorus, and magnesium, the thoracic duct was similar to the arteries, but not to the azygos vein.

Aged↗

PubMed2004

Age-related changes of elements and relationships among elements in human tendons and ligaments.

To elucidate compositional changes of the tendons and ligaments with aging, the authors investigated age-related changes of element contents in the insertion tendons of the biceps brachii muscle, central tendons of the diaphragma, Achilles' tendons, posterior longitudinal ligaments (PLLs) of the cervical spine, ligamenta capitum femorum, and anterior cruciate ligaments. After ordinary dissections by medical students, the three tendons and three ligaments were resected and element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the elements, such as Ca, P, S, Mg, Na, Zn, and Fe, did not change significantly in the three tendons and two ligaments with aging, except for the PLLs where Ca and Mg increased significantly with aging and Fe decreased significantly with aging. With regard to the relationships among elements, the common finding that there were significant correlations between Ca and P contents and between Ca and Mg contents was obtained in the three ligaments. Likewise, the common finding that there was a significant correlation between Ca and Mg contents was obtained in the three tendons. Regarding the relationship between Ca and P contents, the three tendons were different from the three ligaments.

Age Factors↗

PubMed1997

[The Chinese total diet study in 1992--macro elements and trace elements].

Ten macro elements and trace elements were directly determined in the 1992 total diet study conducted in four districts of China from north to south. The intake of these elements was evaluated. The levels of intake for seasonal variation and for different age groups were reported. The results showed that the intakes of Ca, P, K, Mg, Zn, Se and Cu were low in children. The intake of Ca, P and Zn was insufficient for adults. The intakes of other seven elements reached or approached their RDA levels, but there were big differences among the 4 districts. The relationships between intakes of Ca/P and Na/K as well as Fe and Cu and iron difficiency anemia were discussed.

Adolescent↗

PubMedDate not supplied

[Trace elements and trace element therapy update].

Starting from the importance of the trace elements in basic biochemical mechanisms from the human organism, the present role of trace elements therapy, as part of allopathic therapy, is discussed. The ideal properties of trace elements, the therapeutic concepts regarding trace elements, the main pharmaceutical forms that contain them, and their most important uses are presented.

Dose-Response Relationship, Drug↗

PubMed1988

[The Drosophila mobile element jockey is a LINE element and contains coding sequences homologous to retroviral proteins].

A detailed investigation of Drosophila melanogaster mobile dispersed repetitive element jockey is performed. Its structural features resemble those of LINE elements. Sequencing of the complete jockey 5020 bp in length revealed two long open reading frames ORF1 and ORF2 overlapping with a frameshift-1. Judging by amino acid homologies, ORF1 encodes a nucleic acid binding protein, characteristic of replication competent retroviruses; the 3' part of ORF2 encodes an RNA-dependent DNA polymerase which has an amino acid sequence, similar to recently published sequences of LINE elements of Drosophila, Trypanosoma and mammals. This fact demonstrates their evolutionary relationship. Sequencing of several deleted copies of jockey revealed the absence of the major part of ORF2, though the rest of the element, including the ends, is highly conservative.

Amino Acid Sequence↗

PubMed1998

[Disturbances in the status of trace elements in cattle from the point of view of herd supervision. 2: New trace elements].

In this bipartite article the current knowledge about trace elements in cattle is reviewed. The second part contains the new trace elements. This group includes the essential elements arsenic, lead, nickel, vanadium, tin, silicon and the accidental elements. Of the last aluminum, boron, cadmium, mercury and thallium have an importance for cattle due to their toxic potential and the risk of contamination of the food originating from the animal.

Aluminum↗

PubMed2005

cAMP response element binding protein (CREB) activates transcription via two distinct genetic elements of the human glucose-6-phosphatase gene.

BACKGROUND: The enzyme glucose-6-phosphatase catalyzes the dephosphorylation of glucose-6-phosphatase to glucose, the final step in the gluconeogenic and glycogenolytic pathways. Expression of the glucose-6-phosphatase gene is induced by glucocorticoids and elevated levels of intracellular cAMP. The effect of cAMP in regulating glucose-6-phosphatase gene transcription was corroborated by the identification of two genetic motifs CRE1 and CRE2 in the human and murine glucose-6-phosphatase gene promoter that resemble cAMP response elements (CRE). RESULTS: The cAMP response element is a point of convergence for many extracellular and intracellular signals, including cAMP, calcium, and neurotrophins. The major CRE binding protein CREB, a member of the basic region leucine zipper (bZIP) family of transcription factors, requires phosphorylation to become a biologically active transcriptional activator. Since unphosphorylated CREB is transcriptionally silent simple overexpression studies cannot be performed to test the biological role of CRE-like sequences of the glucose-6-phosphatase gene. The use of a constitutively active CREB2/CREB fusion protein allowed us to uncouple the investigation of target genes of CREB from the variety of signaling pathways that lead to an activation of CREB. Here, we show that this constitutively active CREB2/CREB fusion protein strikingly enhanced reporter gene transcription mediated by either CRE1 or CRE2 derived from the glucose-6-phosphatase gene. Likewise, reporter gene transcription was enhanced following expression of the catalytic subunit of cAMP-dependent protein kinase (PKA) in the nucleus of transfected cells. In contrast, activating transcription factor 2 (ATF2), known to compete with CREB for binding to the canonical CRE sequence 5'-TGACGTCA-3', did not transactivate reporter genes containing CRE1, CRE2, or both CREs derived from the glucose-6-phosphatase gene. CONCLUSIONS: Using a constitutively active CREB2/CREB fusion protein and a mutant of the PKA catalytic subunit that is targeted to the nucleus, we have shown that the glucose-6-phosphatase gene has two distinct genetic elements that function as bona fide CRE. This study further shows that the expression vectors encoding C2/CREB and catalytic subunit of PKA are valuable tools for the study of CREB-mediated gene transcription and the biological functions of CREB.

Cyclic AMP Response Element-Binding Protein↗

PubMed1996

Partial repression of human gamma-globin genes by LCR element HS3 when linked to beta-globin genes and LCR element HS2 in MEL cells.

Clues for overcoming fetal (gamma-) globin gene repression in adult human erythroid cells may come from understanding why repression of isolated gamma-globin genes has not previously been achieved in the adult erythroid environment of mouse erythroleukemia cells (MEL). Repression of human gamma-globin genes has been demonstrated in MEL cells when transferred as part of the entire beta-globin gene cluster packaged in chromatin. Major differences in these approaches are prior packaging into chromatin and the presence of additional sequences, notably from the locus control region (LCR). In this report we focus on the contribution to gamma-globin gene repression that multiple elements of the LCR may have. We first show preferential activation of beta-globin genes over gamma-globin genes in MEL cells when linked to each other and to LCR sequences containing the core elements of DNase I hypersensitive sites 4, 3, and 2. Removal of the HS4 element had no effect, however, removal of the 225 bp HS3 core element resulted in a five-fold increase in gamma-globin gene expression. The enhancer 3' to the A gamma-globin gene also had no apparent effect on gamma-globin gene expression. These results provide first evidence of gamma-globin gene repression involving the core region of HS3 in the presence of the core region of HS2 and a beta-globin gene. A mechanism for repression involving sequestration of the gamma-promoter away from the strong enhancer activity of HS2 is proposed.

Animals↗

PubMed1993

Sp1 binds to the adhesion-molecule-on-glia regulatory element that functions as a positive transcription regulatory element in astrocytes.

We analyzed cis-acting elements regulating the expression of the gene encoding adhesion molecule on glia (AMOG) in primary cultured astrocytes from newborn rat cerebrum and cerebellum. The relative promoter activities among the series of 5' sequential deletion mutants are similar to those observed in B103 (rat neuroblastoma cell line) cells. The previously identified AMRE (AMOG regulatory element) of the GAGGCGGGG sequence functions as a positive regulatory element, not only in B103 cells, but also in astrocytes. Binding factors to the element were identified as Sp1 based on the following observations using nuclear extracts from the astrocytes and B103 cells: (1) The interaction of the factors with AMRE analyzed by DNase I footprinting and methylation interference analyses was similar to that of Sp1; (2) The binding of the factors to AMRE competed with an oligonucleotide containing the authentic Sp1 consensus sequence; (3) Sp1-specific antibody interfered with the formation of the AMRE gel retardation complexes. The functional implications of the factors in AMOG gene regulation are discussed.

Adenosine Triphosphatases↗

PubMed2006

Dual nebulizer sample introduction system for simultaneous determination of volatile elemental hydrides and other elements.

A dual sample introduction system was explored for volatile hydride generation in inductively coupled plasma-optical emission spectrometry (ICP-OES) performed in the radially viewed mode. The system consists of two pneumatic nebulizers connected to the conventional spray chamber of the instrument via a simple adaptor. This configuration permits hydride generation but still allows other elements to be determined by pneumatic nebulization. This work was focused on the optimization of the plasma operating conditions for the determination of As, Hg, Sb and Se and other elements. The excitation conditions of the ICP-OES instrument operated with the dual sample introduction system were also explored. Results showed that the analytical performance of the dual system for the determination of As, Hg, Sb and Se was superior to those of conventional nebulization systems. The dual system also enabled the determination of elements that do not form volatile hydrides, but with less sensitivity than conventional nebulization systems. An evaluation of the plasma robustness showed that the gases generated in the hydride reactions did not significantly affect the plasma discharge. Similar to conventional hydride generation techniques, the analysis was susceptible to nonspectroscopic interferences produced by transition metals. Finally, the applicability of the dual nebulization system to practical ICP-OES studies was demonstrated by determining the trace elements in an oyster tissue standard reference material.

Journal Article↗

PubMed1994

Analysis of an insulin gene transcription control element. Positive and negative regulation appears to be mediated by different element sequences.

Pancreatic beta-cell-type-specific transcription of the insulin gene is controlled by cis-acting sequence elements lying within its enhancer region. An essential element required for expression is the insulin control element (ICE). The activity of this element is regulated by both positive- and negative-acting transcription factors. In this study, we have identified the nucleotide sequences within the ICE that are required for repression in noninsulin producing cells. Our results indicate that the cis-acting sequences involved in negative control are distinct from those required in activating expression in beta cells.

Animals↗