SEARCH · PubMed Health

Results for “Boxing”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources

PubMed1999

A family of mammalian F-box proteins.

Ubiquitin-mediated destruction of regulatory proteins is a frequent means of controlling progression through signaling pathways [1]. F-box proteins [2] are components of modular E3 ubiquitin protein ligases called SCFs, which function in phosphorylation-dependent ubiquitination ([3] [4] [5], reviewed in [6] [7]). F-box proteins contain a carboxy-terminal domain that interacts with substrates and a 42-48 amino-acid F-box motif which binds to the protein Skp1 [2] [3] [4]. Skp1 binding links the F-box protein with a core ubiquitin ligase composed of the proteins Cdc53/Cul1, Rbx1 (also called Hrt1 and Roc1) and the E2 ubiquitin-conjugating enzyme Cdc34 [8] [9] [10] [11]. The genomes of the budding yeast Saccharomyces cerevisiae and the nematode worm Caenorhabditis elegans contain, respectively, 16 and more than 60 F-box proteins [2] [7]; in S. cerevisiae, the F-box proteins Cdc4, Grr1 and Met30 target cyclin-dependent kinase inhibitors, G1 cyclins and transcriptional regulators for ubiquitination ([3] [4] [5] [8] [10], reviewed in [6] [7]). Only four mammalian F-box proteins (Cyclin F, Skp1, beta-TRCP and NFB42) have been identified so far [2] [12]. Here, we report the identification of a family of 33 novel mammalian F-box proteins. The large number of these proteins in mammals suggests that the SCF system controls a correspondingly large number of regulatory pathways in vertebrates. Four of these proteins contain a novel conserved motif, the F-box-associated (FBA) domain, which may represent a new protein-protein interaction motif. The identification of these genes will help uncover pathways controlled by ubiquitin-mediated proteolysis in mammals.

Amino Acid Sequence↗

PubMed2001

Catharanthus roseus G-box binding factors 1 and 2 act as repressors of strictosidine synthase gene expression in cell cultures.

The enzyme encoded by the strictosidine synthase (Str) gene catalyses a key step in the biosynthesis of therapeutically valuable terpenoid indole alkaloids. In Catharanthus roseus the Str gene was shown to be regulated by a wide variety of signals including auxin, methyl jasmonate and fungal elicitors in cell suspension cultures and by tissue-specific control in plant organs. The Str promoter contains a functional G-box (CACGTG) cis-regulatory sequence. In order to understand better the mechanisms involved in the regulation of Str gene expression, we isolated the C. roseus cDNAs encoding G-box binding factors Crgbf1 and Crgbf2. The binding specificity of their protein products CrGBF1 and CrGBF2 was analysed by competitive electrophoresis mobility and saturation binding assays. CrGBF1 had a high binding specificity for class I G-boxes including the Str G-box. CrGBF1 showed a lower affinity for class II G-boxes and for the G-box-like element (AACGTG) found in the tryptophan decarboxylase (Tdc) gene which encodes another enzyme involved in TIA biosynthesis. CrGBF2 showed a high affinity for all types of G-boxes tested and to a lesser extent for the Tdc G-box-like element. Transient bombardment experiments demonstrated that both CrGBF1 and CrGBF2 can act in vivo as transcriptional repressors of the Str promoter via direct interaction with the G-box. These data indicate that GBFs may play functional role in the regulation of expression of the terpenoid indole alkaloid biosynthetic gene Str.

Amino Acid Sequence↗

PubMed2000

Effect of bilirubin UDP glucuronosyltransferase 1 gene TATA box genotypes on serum bilirubin concentrations in chronic liver injuries.

TATA box abnormality in the promoter region of the bilirubin UDP glucuronosyltransferase 1 gene has been reported to cause Gilbert's syndrome in white subjects. It has also been reported that the majority of Japanese patients with Gilbert's syndrome are heterozygous for Gly71Arg in the coding region of this gene. On the other hand, some patients with chronic hepatitis often show signs of unexpected hyperbilirubinemia. The aims of this study were to determine which of the genetic variations, TATA box genotype or codon 71 genotype, is most closely related to serum bilirubin concentrations, and whether the TATA box genotype has an effect on serum bilirubin concentrations in patients with hepatitis C-associated chronic liver diseases. In a sample of 300 individuals selected from among the general Japanese population, mean concentrations of total serum bilirubin differed significantly among TATA box genotypes, but not among codon 71 genotypes. Concentration of total serum bilirubin was significantly correlated with TATA box genotypes. In 211 patients with hepatitis C-associated chronic liver diseases, mean concentrations of total serum bilirubin also differed significantly among TATA box genotypes. In patients with chronic hepatitis C, concentration of total serum bilirubin was significantly correlated with TATA box genotypes. In summary, TATA box genotypes, but not codon 71 genotypes, are closely related to serum bilirubin concentrations. TATA box genotypes should therefore be considered when evaluating hepatic function by serum bilirubin concentrations in cases of hepatitis C-associated chronic liver diseases.

Adult↗

PubMed2002

The F-box subunit of the SCF E3 complex is encoded by a diverse superfamily of genes in Arabidopsis.

The covalent attachment of ubiquitin is an important determinant for selective protein degradation by the 26S proteasome in plants and animals. The specificity of ubiquitination is often controlled by ubiquitin-protein ligases (or E3s), which facilitate the transfer of ubiquitin to appropriate targets. One ligase type, the SCF E3s are composed of four proteins, cullin1/Cdc53, Rbx1/Roc1/Hrt1, Skp1, and an F-box protein. The F-box protein, which identifies the targets, binds to the Skp1 component of the complex through a degenerate N-terminal approximately 60-aa motif called the F-box. Using published F-boxes as queries, we have identified 694 potential F-box genes in Arabidopsis, making this gene superfamily one of the largest currently known in plants. Most of the encoded proteins contain interaction domains C-terminal to the F-box that presumably participate in substrate recognition. The F-box proteins can be classified via a phylogenetic approach into five major families, which can be further organized into multiple subfamilies. Sequence diversity within the subfamilies suggests that many F-box proteins have distinct functions and/or substrates. Representatives of all of the major families interact in yeast two-hybrid experiments with members of the Arabidopsis Skp family supporting their classification as F-box proteins. For some, a limited preference for Skps was observed, suggesting that a hierarchical organization of SCF complexes exists defined by distinct Skp/F-box protein pairs. Collectively, the data shows that Arabidopsis has exploited the SCF complex and the ubiquitin/26S proteasome pathway as a major route for cellular regulation and that a diverse array of SCF targets is likely present in plants.

Amino Acid Sequence↗

PubMed1988

Characterization of the cDNA encoding a protein binding to the major histocompatibility complex class II Y box.

The expression of HLA class II genes is regulated by a series of cis-acting elements and trans-acting factors. Several cis-acting elements have been identified and have been termed the Z box, X box, Y box, octamer, and "TATA" box. The Y box contains an inverted CCAAT box. By probing a phage lambda gt11 library with double-stranded oligonucleotides, we have directly isolated a cDNA encoding a Y box-binding protein designated YB-1. YB-1 binding has an absolute requirement for the CCAAT box and relative specificity for the Y box. It has a Mr of 35,414, contains 18% basic residues, and contains putative nuclear localization signals. An inverse correlation of YB-1 and HLA-DR beta chain mRNA levels suggests that YB-1 is a negative regulatory factor.

Amino Acid Sequence↗

PubMed2002

Circadian Transcription. Thinking outside the E-Box.

The E-Box is a widely used DNA control element. Despite its brevity and broad distribution the E-Box is a remarkably versatile sequence that affects many different genetic programs, including proliferation, differentiation, tissue-specific responses, and cell death. The circadian clock is one of the latest pathways shown to employ this element. In this context, E-Boxes are likely to play a key role in establishing the robust waves of gene expression characteristic of circadian transcription. The regulatory flexibility of the E-Box hinges on the sequence ambiguity allowed at its core, the strong influence of the surrounding sequences, and the recruitment of spatially and temporally regulated E-Box-binding factors. Therefore, understanding how a particular E-Box can accomplish a specific task entails the identification and systematic analysis of these cis- and trans-acting E-Box modifiers. In the present study we compared the E-Box-containing minimal promoters of vasopressin and cyclin B1, two genes that can respond to the transcriptional oscillators driving the circadian clock and cell cycle, respectively. Results of this comparison will help elucidate the manner in which discreet DNA modules associate to either augment or restrain the activation of potential circadian E-Boxes in response to competing regulatory signals.

3T3 Cells↗

PubMed2004

Evaluation of myc E-box phylogenetic footprints in glycolytic genes by chromatin immunoprecipitation assays.

Prediction of gene regulatory sequences using phylogenetic footprinting has advanced considerably but lacks experimental validation. Here, we report whether transcription factor binding sites predicted by dot plotting or web-based Trafac analysis could be validated by chromatin immunoprecipitation assays. MYC overexpression enhances glycolysis without hypoxia and hence may contribute to altered tumor metabolism. Because the full spectrum of glycolytic genes directly regulated by Myc is not known, we chose Myc as a model transcription factor to determine whether it binds target glycolytic genes that have conserved canonical Myc binding sites or E boxes (5'-CACGTG-3'). Conserved canonical E boxes in ENO1, HK2, and LDHA occur in 31- to 111-bp islands with high interspecies sequence identity (>65%). Trafac analysis revealed another region in ENO1 that corresponds to a murine region with a noncanonical E box. Myc bound all these conserved regions well in the human P493-6 B lymphocytes. We also determined whether Myc could bind nonconserved canonical E boxes found in the remaining human glycolytic genes. Myc bound PFKM, but it did not significantly bind GPI, PGK1, and PKM2. Binding to BPGM, PGAM2, and PKLR was not detected. Both GAPD and TPI1 do not have conserved E boxes but are induced and bound by Myc through regions with noncanonical E boxes. Our results indicate that Myc binds well to conserved canonical E boxes, but not nonconserved E boxes. However, the binding of Myc to unpredicted genomic regions with noncanonical E boxes reveals a limitation of phylogenetic footprinting. In aggregate, these observations indicate that Myc is an important regulator of glycolytic genes, suggesting that MYC plays a key role in a switch to glycolytic metabolism during cell proliferation or tumorigenesis.

Base Sequence↗

PubMed2003

Roles of the conserved CCAAT and GC boxes of the human and mouse type II transforming growth factor-beta receptor genes.

Embryonal carcinoma (EC) cells are used widely to study the molecular mechanisms that regulate the transcription of genes during mammalian embryogenesis. The type II transforming growth factor-beta receptor (TbetaR-II) gene is expressed at very low levels by mouse EC cells prior to differentiation. Differentiation of EC cells results in increases of both the steady-state levels of TbetaR-II mRNA and the activity of the TbetaR-II promoter. Several cis-regulatory elements have been shown previously to regulate the TbetaR-II gene. This study focuses on the role of a CCAAT box and three GC boxes in the regulation of the human and mouse TbetaR-II promoters in EC-differentiated cells. We demonstrate that the CCAAT box and two flanking GC boxes, Sp A and Sp B, function as positive regulatory elements in the human TbetaR-II promoter, and that the transcription factor complex NF-Y positively regulates the human TbetaR-II promoter through the CCAAT box motif. We also show that the CCAAT box and the downstream GC box Sp B, which are conserved between the human and mouse promoters, behave as positive regulatory elements in the mouse TbetaR-II promoter. In addition, we demonstrate that the transcription factor Sp1 can bind to the Sp B GC box in vitro. Finally, we show that a GC box located 25 bp upstream of the major transcription start site of the TbetaR-II gene plays a minimal role in the function of the TbetaR-II promoter in EC-differentiated cells. Together, our studies highlight important differences and similarities in the cis-regulatory elements that regulate the human and mouse TbetaR-II promoters.

Animals↗

PubMed2002

Hormonal and behavioral responses of starlings during a confrontation with males or females at nest boxes during the reproductive season.

We investigated in an aviary experiment the behavioral and hormonal responses of European starlings (Sturnus vulgaris) that were moved from a same sex group to an aviary containing either a nest box alone, a nest box and another male, or a nest box and a female. Luteinizing hormone (LH) and testosterone (T) levels increased significantly and independently of the situation, suggesting that nest boxes were the most important stimulus affecting the levels of these hormones. Some birds occupied more than two boxes (winners), and others a single or no box (losers). Levels of T increased less in males that did not acquire a nest box. However, the increase in LH was similar in all males after the test. Singing was positively correlated with T levels. Winners started singing earlier and sang more during a contest than losers. In the presence of females LH increased more in winners than in losers, while the increase in T was similar in both groups. In females, there was no increase in T but LH increased in the presence of males. Levels were higher in females paired with winners than in females paired with losers. Finally, winners advertised their nest boxes more frequently than losers. These results indicate that within a relatively short time frame levels of LH and T increase following the transfer from a flock to a territorial situation and can react independently from each other depending on reproductive circumstances. For males, the possession of a nest box and, for females, the qualities of the male seemed to be the most important factors stimulating reproduction.

Animals↗

PubMed2000

Low temperature regulated DEAD-box RNA helicase from the Antarctic archaeon, Methanococcoides burtonii.

DEAD-box RNA helicases, by unwinding duplex RNA in bacteria and eukaryotes, are involved in essential cellular processes, including translation initiation and ribosome biogenesis, and have recently been implicated in enabling bacteria to survive cold-shock and grow at low temperature. Despite these critical physiological roles, they have not been characterized in archaea. Due to their presumed importance in removing cold-stabilised secondary structures in mRNA, we have characterised a putative DEAD-box RNA helicase gene (deaD) from the Antarctic methanogen, Methanococcoides burtonii. The encoded protein, DeaD is predicted to contain a core element involved in ATP hydrolysis and RNA-binding, and an unusual C-terminal domain that contains seven perfect, trideca-peptide, direct repeats that may be involved in RNA binding. Alignment and phylogenetic analyses were performed on the core regions of the M. burtonii and other DEAD-box RNA helicases. These revealed a loose but consistent clustering of archaeal and bacterial sequences and enabled the generation of a prokaryotic-specific consensus sequence. The consensus highlights the importance of residues other than the eight motifs that are often associated with DEAD-box RNA helicases, as well as de-emphasising the importance of the "A" residue within the "DEAD" motif. Cells growing at 4 degrees C contained abundant levels of deaD mRNA, however no mRNA was detected in cells growing at 23 degrees C (the optimal temperature for growth). The transcription initiation site was mapped downstream from an archaeal box-A element (TATA box), which preceded a long (113 nucleotides) 5'-untranslated region (5'-UTR). Within the 5'-UTR was an 11 bp sequence that closely matches (nine out of 11) cold-box elements that are present in the 5'-UTRs of cold-shock induced genes from bacteria. To determine if the archaeal 5'-UTR performs an analagous function to the bacterial 5'-UTRs, the archaeal deaD 5'-UTR was transcribed in E. coli under the control of the cspA promoter and transcriptional terminator. It has previously been reported that overexpression of the cspA 5'-UTR leads to an extended cold-shock response due to the 5'-UTR titrating cellular levels of a cold-shock repressor protein(s). In our hands, the cold-shock protein profiles resulting from overexpression of Escherichia coli cspA and M. burtonii deaD 5'-UTRs were similar, however they did not differ from those for the overexpression of a control plasmid lacking a 5'-UTR. In association with other recent data from E. coli, our results indicate that the role of the 5'-UTR in gene regulation is presently unclear. Irrespective of the mechanisms, it is striking that highly similar 5'-UTRs with cold-box elements are present in cold induced genes from E. coli, Anabaena and M. burtonii. This is the first study examining low temperature regulation in archaea and provides initial evidence that gene expression from a cold adapted archaeon involves a bacterial-like transcriptional regulatory mechanism. In addition, it provides the foundation for further studies into the function and regulation of DEAD-box RNA helicases in archaea, and in particular, their roles in low temperature adaptation.

5' Untranslated Regions↗

PubMed1987

Cloning and expression of rat homeo-box-containing sequences.

Six rat homeo-box-containing DNA sequences have been isolated by screening a genomic library with a probe derived from an Antennapedia (Antp) cDNA clone of Drosophila melanogaster. Sequence determination of two of the clones containing the homeo-box regions reveals a 180-nucleotide(nt) domain sharing more than 80% homology at the nucleotide level and more than 90% homology at the amino acid level with the homeo-box from the Antp gene and from homeo-boxes of other metazoan species. Genomic blotting experiments suggest that the two homeo-box-containing DNA regions are present in one or two copies per haploid rat genome. Northern blot analysis of RNA has shown that the rat homeo-box sequences are expressed in a tissue-specific manner; transcripts were detected in the spinal cord and kidney, but not in brain, testis, liver, and spleen. The rat nucleotide sequences lying outside the 180-nt homeo-box domain share virtually no sequence homology with the Antp flanking regions. However, one clone does show an equally high degree of amino acid homology within the homeo-box and its immediate flanking region with a putative homologous gene in mouse. The result suggests that some of the mammalian homeo-box-containing genes are conserved in evolution and may serve important cellular or developmental functions.

Animals↗

PubMed1988

An engrailed class homeo box gene in sea urchins.

The homeo box, a conserved DNA element first recognized in Drosophila development-controlling genes, is present in the genomes of many higher metazoan species and provides a valuable probe for the isolation of regulatory genes from diverse phylogenetic groups. We have employed these probes to isolate and study the homeo-box genes in sea urchins. As in other species, the sea urchin homeo boxes fall into at least two classes defined by nucleotide sequence similarity to the homeo boxes of the Drosophila Antennapedia (Antp) and engrailed (en) genes. In this study, we characterize the only detectable sea urchin en class homeo box. Its nucleotide sequence similarity and lack of an intron indicate that it is more closely related to the two mouse en class homeo boxes than to the two Drosophila en class homeo boxes. These relationships are most parsimoniously explained if the single sea urchin en class homeo-box gene represents the primitive condition and the two mouse and the two Drosophila en class homeo-box genes represent independent duplications which occurred in the evolutionary lines leading to the vertebrates and arthropods, respectively. The most abundant en class gene transcripts detected by gel transfer analysis of RNA extracted from sea urchin tissues were found in Aristotle's lantern. Rare transcripts were present in ovary, testis and coelomocytes.

Amino Acid Sequence↗

PubMed1989

The chicken homeo box genes CHox1 and CHox3: cloning, sequencing and expression during embryogenesis.

Several Drosophila genes involved in the control of segmentation and segment identity share a 183-bp conserved sequence termed homeo box. Homeo box sequences have been detected and cloned from the genomes of insects like Drosophila to vertebrates such as mouse and man. Two chicken homeo box genes CHox1 and CHox3, are described. Cloning of the CHox1 and CHox3 homeo boxes was performed using Drosophila and murine homeo box sequences as probes under low-stringency conditions. Analysis of both chicken homeo box sequences revealed them to be homeo boxes that have diverged from the Antennapedia class with homologies to homeo boxes of other organisms in the range of 75-42% at the nucleotide level and 69-41% at the protein level. Analysis of CHox3 expression during early embryo development showed that the gene codes for five transcripts 1.3, 1.9, 2.6, 5.6 and 7.9 kb in size. Three of the transcripts (1.3, 1.9 and 5.6 kb) are also recognized by a flanking non-homeo box containing probe. The levels of the different transcripts changed during the first five days of development. The most abundant transcripts (1.3 and 1.9 kb) are already present at the time the egg is laid. Their transcription peaks at day 1 of incubation and then decreases. The CHox1 transcripts are present at very low levels between days 2.5 and 4 of development. These two chicken genes represent bona fide Hox genes in a branch of vertebrates that evolved parallel to mammals.

Amino Acid Sequence↗

PubMed2006

Solution structure of the RBCC/TRIM B-box1 domain of human MID1: B-box with a RING.

B-box domains are a defining feature of the tripartite RBCC (RING, B-box, coiled-coil) or TRIM proteins, many of which are E3 ubiquitin ligases. However, little is known about the biological function of B-boxes. In some RBCC/TRIM proteins there is only a single B-box (type 2) domain, while others have both type 1 and type 2 B-box domains in tandem adjacent to their RING domain. These two types of B-boxes share little sequence similarity, except the presence of cysteine and histidine residues: eight in most B-box1 domains and seven in B-box2 domains. We report here the high-resolution solution structure of the first B-box1 domain (from the human RBCC protein, MID1) based on 670 nuclear Overhauser effect (NOE)-derived distance restraints, 12 hydrogen bonds, and 44 dihedral angles. The domain consists of a three-turn alpha-helix, two short beta-strands, and three beta-turns, encompassing Val117 to Pro164, which binds two zinc atoms. One zinc atom is coordinated by cysteine residues 119, 122, 142, 145, while cysteine 134, 137 and histidine 150, 159 coordinate the other. This topology is markedly different from the only other B-box structure reported; that of a type 2 B-box from Xenopus XNF7, which binds a single zinc atom. Of note, the B-box1 structure closely resembles the folds of the RING, ZZ and U-box domains of E3 and E4 ubiquitin enzymes, raising the possibility that the B-box1 domain either has E3 activity itself or enhances the activity of RING type E3 ligases (i.e. confers E4 enzyme activity). The structure of the MID1 B-box1 also reveals two potential protein interaction surfaces. One of these is likely to provide the binding interface for Alpha 4 that is required for the localized turnover of the catalytic subunit of PP2A, the major Ser/Thr phosphatase.

Amino Acid Sequence↗

PubMed2001

Identification of novel, cardiac-restricted transcription factors binding to a CACC-box within the human cardiac troponin I promoter.

OBJECTIVES: The expression of the human cardiac troponin I (hTnIc) gene is developmentally regulated and tissue-specific. In analysing the putative binding elements within the proximal promoter, a CACC-box sequence overlapping a consensus Sp1 element has been identified. The aim of this study was to characterise the factors binding to this element and to determine their importance in the transcriptional activity of the promoter. METHODS: A combination of supershift and competition electrophoretic mobility shift assays (EMSA) were used to identify the binding of factors to the overlapping CACC-box/Sp1 consensus element. The functional importance of this element was tested by transient transfection into primary neonatal rat cardiac myocytes in culture. RESULTS: At least four factors were able to interact with this region including the zinc finger proteins Sp1, Sp3 and two potentially novel factors. Whereas both Sp1 and Sp3 bound to the consensus Sp1 element, and to a lesser extent the CACC-box, two of the complexes required the intact CACC-box for binding. Site-directed mutagenesis of this region showed that the CACC-box is essential for hTnIc promoter-reporter activity. Further characterisation using EMSA indicated that the factors binding the hTnIc CACC-box are unlikely to be zinc finger proteins as they are insensitive to the addition of divalent cation chelating agents. They were also unable to bind to other known CACC-box elements. These factors are present in both human and rat cardiac muscle but absent from a number of cell lines including several derived from skeletal muscle. CONCLUSION: The human cardiac troponin I gene promoter requires an upstream CACC-box element for full activity. This element binds at least two complexes which represent novel, tissue-restricted DNA-binding activity present in the heart which we have named HCB1 and HCB2 for heart CACC-box binding factors.

Animals↗

PubMed1998

Sequences flanking the E-box contribute to cooperative binding by c-Myc/Max heterodimers to adjacent binding sites.

Previously, we have shown that c-Myc/Max heterodimers, bind cooperatively to the two adjacent, canonical E-boxes (CACGTG) located in the rat ornithine decarboxylase (ODC) gene. In order to study this in more detail, we changed the length of the linker that separates the two E-boxes, as well as their flanking sequences. We found that high affinity, cooperative binding requires a minimal linker length of 1-4 bp and that the binding affinity is influenced by E-box flanking sequences. Binding to the c-Myc responsive element of prothymosin alpha, containing both a canonical and a noncanonical E-box (CAAGTG) was also studied. As shown by DNAseI footprinting analysis, only the canonical E-box is bound by c-Myc/Max and c-Max/Max dimers. Replacing the noncanonical site with a canonical E-box only partially restored high affinity, cooperative binding. By making hybrid fragments between ODC and prothymosin alpha, we found that nucleotides in the linker between the E-boxes influence the affinity of c-Myc/Max heterodimers. Taken together, our results show that E-box sequences and sequences in the linker separating both E-boxes influence cooperative, high affinity binding by c-Myc/Max dimers.

Animals↗

PubMed2001

Okadaic acid induces transcription of junB through a CCAAT box and NF-Y.

The shellfish toxin, okadaic acid (OA), is a potent tumor promoter that induces expression of the proto-oncogene junB in mouse keratinocyte 308 cells. Here we show, through deletion analysis of the junB promoter, that sequences near the TATA box conferred transcriptional induction by OA. Transient transfections of luciferase constructs bearing the junB promoter with single mutations in various cis elements demonstrated that a promoter containing a mutated CCAAT box could not be induced by OA. When this CCAAT box was inserted into a heterologous promoter construct, OA induction was dependent on an intact CCAAT box. Flanking cis elements located near the CCAAT box, although not required for OA inducibility, did play a role in the basal level of transcription. NF-Y was shown by EMSA to bind to the CCAAT box. OA induction from the junB CCAAT box was blocked by dominant negative NF-YA as well as the CCAAT box-dependent anticancer drug, ET-473. Expression of a lexA/NF-YA chimeric protein demonstrated that OA induction was dependent on the binding of NF-Y family members. These studies demonstrate that OA can mediate transcriptional activation of junB through the classical CCAAT box and that transcription factor NF-Y plays a functional role in the induction.

Animals↗

PubMed1999

A TM3-like MADS-box gene from Eucalyptus expressed in both vegetative and reproductive tissues.

MADS-box genes in plants are a diverse class of transcription factors that are involved in regulating developmental processes, particularly meristem and organ identity during floral development. They are characterized by a highly conserved MADS-box domain of 59 amino acids that binds to specific DNA sequences. We report the characterization of a cDNA clone, ETL (Eucalyptus TM3 Like), from Eucalyptus globulus subspecies bicostata encoding a putative transcription factor of the MADS-box class that is strongly expressed in both vegetative and floral tissues, suggesting that it regulates processes other than floral development. The clone was isolated from a floral bud cDNA library with a probe generated from Eucalyptus genomic DNA by PCR using degenerate primers to the MADS-box of the floral regulatory gene APETALA 1. The ETL cDNA clone encodes a putative protein of 206 amino acids that contains an N-terminal MADS-box and a helical domain of approx. 60 amino acids predicted to form a coiled-coil (K-box). These structural features are characteristic of plant MADS-box proteins. The MADS-box domain contains all the signature residues of a class of MADS-box genes typified by the tomato gene TM3 and overall, ETL shows 56% amino acid identity to TM3. Like TM3, the ETL gene is expressed in both vegetative and reproductive organs, predominantly in root and shoot meristems and organ primordia, as well as in developing male and female floral organs.

Amino Acid Sequence↗