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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To elucidate how methylation of specific sites in plant DNA might control transcription, we examined the effect of DNA methylation at CpG sequences on the binding of plant nuclear factors to an oligonucleotide duplex containing the consensus sequence for mammalian CREB (cAMP response element binding protein). CREB is part of the ATF (activating transcription factor) family of mammalian proteins specifically binding to 5'-TGACGTCA-3' and related sequences. Proteins recognizing the CREB-specific ligand were identified in nuclear extracts of pea seeds, wheat germ, cauliflower, and soybean leaves using electrophoretic mobility shift assays. Cytosine methylation inhibited binding of this protein in all these extracts, and so this sequence-specific DNA-binding activity is referred to as methylation-inhibited binding protein 1 (MIB-1). Sites somewhat similar to that of the CREB ligand are found in the upstream regions of a wheat histone H3 gene and tomato and pea ribulose 1,5-bisphosphate carboxylase genes. These sites were bound preferentially by distinct proteins that may be related to the previously described plant proteins HBP-1, HSBF, ASF-1, or GBF. Methylation of cytosine residues at these sites and at a site for MIB-1 located upstream of a soybean proline-rich protein gene also reduced specific binding with all the nuclear extracts tested. Similarly, substitution of the central CpG dinucleotide with TpG decreased binding.
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PMID:CpG methylation inhibits binding of several sequence-specific DNA-binding proteins from pea, wheat, soybean and cauliflower. 183 Oct 56

We identified two novel DNA-binding proteins, ssDBP-1 and ssDBP-2, in wheat germ nuclear extract that interact with the proximal sequences of the promoter regions of the wheat histone H3 and H4 genes. Mobility shift and methylation interference assays have demonstrated that these factors specifically bind to the single-strand DNA which partially overlaps the hexamer and octamer cis-elements of the H3 promoter. Both proteins are distinguishable from HBP-1a and HBP-1b which specifically bind to the H3 hexamer sequence. These ssDNA-binding proteins are supposed to regulate the transcription of the wheat histone genes.
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PMID:Sequence-specific single-strand DNA-binding proteins that interact with the regulatory regions of wheat histone H3 and H4 genes. 203 33

A majority of histone genes are expressed in the S phase during the cell cycle. Using the gene expression system of transformed sunflower cells into which wheat histone H3 gene was introduced by the Ti-plasmid gene transfer technique, we determined three cis-acting control sequences (hexameric, octameric, and nonameric motifs) which seemed to confer the S-phase-specific transcription of wheat histone genes. Furthermore, as candidates for regulatory transcription factors, three nuclear DNA-binding proteins HBP-1a, HBP-1b, and HBP-2 that interact with the hexameric and nonameric motifs were identified. The structural analysis of the cDNA of HBP-1a revealed that a nuclear protein has the leucine-zipper structure and a DNA-binding motif. The hexameric motif in the H3 gene was also seen in cauliflower mosaic virus 35S (CaMV 35S) promoter and shown to function as a regulatory element of this promoter. The wheat HBP-1b can interact with the hexameric motif of the CaMV 35S promoter. Much attention has been paid to the significance of the hexameric sequences within the H3 and CaMV 35S promoters and the DNA-binding proteins HBP-1a and HBP-1b.
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PMID:Cell cycle-regulated gene expression in transgenic plant cells. 227 56

HBP-1 is a sequence-specific DNA-binding protein that interacts with the hexameric sequence ACGTCA, the putative cis-acting element of the wheat histone H3 gene. Gel mobility shift and DNase I footprint analyses showed that this protein interacts with homologous sequences in the regulatory regions for the transcription of the cauliflower mosaic virus (CaMV) 35S RNA and nopaline synthase (NOS) genes, evidence that HBP-1 may bind to hexameric sequences in the regulatory regions of various genes. An HBP-1-like protein, indistinguishable from wheat HBP-1 in its the DNA-binding specificity, is present in sunflower nuclear extract, an indication that HBP-1-like DNA-binding proteins also exist in dicots.
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PMID:Wheat nuclear protein HBP-1 binds to the hexameric sequence in the promoter of various plant genes. 260 42

A novel DNA-binding protein that specifically interacts with the hexameric sequence ACGTCA in the regulatory region of the wheat histone H3 gene has been identified in wheat nuclear extract and designated HBP-1a. The nuclear protein HBP-1 previously identified as a DNA-binding protein that interacts with hexameric sequences in the H3, cauliflower mosaic virus (CaMV) 35 S RNA, and nopaline synthase (NOS) promoter regions therefore has been renamed HBP-1b. The flanking sequences that surround the hexameric sequence may account for the difference in the binding properties of HBP-1a and HBP-1b.
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PMID:Multiplicity of the DNA-binding protein HBP-1 specific to the conserved hexameric sequence ACGTCA in various plant gene promoters. 268 Jun 1

The structure and function of transcription factors of higher plants was studied by isolating cDNA clones encoding a wheat sequence-specific DNA binding protein. A hexameric nucleotide motif, ACGTCA, is located upstream from the TATA box of several plant histone genes. It has been suggested that this motif is essential for efficient transcription of the wheat histone H3 gene. A wheat nuclear protein, HBP-1 (histone DNA binding protein-1), which specifically binds to the hexameric motif, has previously been identified as a putative transcription factor. A cDNA clone encoding HBP-1 has been isolated on the basis of specific binding of HBP-1 to the hexameric motif. The deduced amino acid sequence indicates that HBP-1 contains the leucine zipper motif, which represents a characteristic property of several eukaryotic transcription factors.
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PMID:A protein that binds to a cis-acting element of wheat histone genes has a leucine zipper motif. 277 48

The type I element (CCACGTCANCGATCCGCG) is a cis-acting element that is essential for the transcriptional regulation of the wheat histone H3 (TH012) gene. The sequence CCACGTCA in the type I element resembles various plant regulatory elements that share an ACGT core sequence, which can be recognized by different basic/leucine zipper (bZIP) proteins. Here we describe the isolation and characterization of wheat cDNA clones encoding three novel bZIP proteins, designated HBP (histone promoter-binding protein)-1a(1), HBP-1a(c14), and HBP-1b(c1). These proteins specifically bind to the ACGT core sequence and, together with previously identified HBP-1a(17) and HBP-1b(c38), constitute a protein family, named the HBP-1 family. Based on their structural characteristics and DNA binding specificities, members of the HBP-1 family can be grouped into HBP-1a and HBP-1b subfamilies. The HBP-1a isoforms are characterized by their N-terminal proline-rich domain and a C-terminal bZIP domain, which binds to the CCACGT motif. In contrast, the HBP-1b isoforms have a bZIP domain at the N terminus, which binds to the ACGTCA motif, and a glutamine-rich domain at the C terminus. All members of both subfamilies interact with the CCACGTCA sequence, but their DNA binding specificities and affinities differ. Since HBP-1a isoforms form heterodimers in all pairwise combinations, heterodimer formation among these bZIP proteins may generate an expanded repertoire of regulatory potential for gene expression in plants.
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PMID:The HBP-1 family of wheat basic/leucine zipper proteins interacts with overlapping cis-acting hexamer motifs of plant histone genes. 814 92

A nonamer motif (CATCCAACG) that is one of the cis-acting elements identified in the proximal promoter region of some wheat histone genes is included in the region that interacts with the wheat DNA-binding protein, HBP (histone gene-binding protein)-2. To obtain structural and functional information about this DNA-binding protein, we attempted to isolate a cDNA clone encoding HBP-2 on the basis of its ability to bind to a nonamer-containing 38-bp DNA fragment. Southwestern screening of a wheat cDNA library with concatenated 38-residue oligonucleotides as the probe produced one candidate clone. Nucleotide sequence analyses of this cDNA clone and the corresponding genomic clone showed that the protein deduced from the nucleotide sequence consisted of 261 amino acids and contained a set of zinc-finger motifs similar to those found in many eukaryotic transcription factors. The protein, named WZF1 (wheat zinc-finger protein 1), which was expressed from the cDNA in Escherichia coli cells, bound specifically and metal-ion-dependently to the nonamer-containing oligonucleotide. The WZF1 mRNA was highly expressed in the root apexes of wheat seedlings, but less so in the proximal portion of young leaves; whereas, histone H3 mRNA was highly expressed in both tissues. The expression patterns of the WZF1 and histone H3 genes in the early stages of germination differed, expression of the WZF1 gene being almost constant but not that of the H3 gene. The relationship of WZF1 and HBP-2 and the possible role of WZF1 in the histone gene expression were discussed.
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PMID:The putative zinc-finger protein WZF1 interacts with a cis-acting element of wheat histone genes. 822 28

The wheat bZIP protein HBP-1a(17) is a putative transcription factor regulating histone gene expression. To delineate the functional domain(s) of this factor, we made a series of effector constructs expressing fusion proteins, in which various portions of HBP-1a(17) are fused to the DNA-binding domain of the yeast transcriptional activator GAL4, in plant cells. When the beta-glucuronidase (GUS) reporter gene, driven by the wheat histone H3 core promoter harboring the GAL4-binding sequence, was co-transfected with such effector genes into tobacco protoplasts, several portions of HBP-1a(17) influenced reporter gene expression. The N-terminal one-third of HBP-1a(17), termed the P region (residues 1-118) due to its Pro content, did not activate the reporter gene, in contrast to the corresponding Pro-rich region of Arabidopsis GBF1 (residues 1-110), which functions as an activation domain. When the P region was divided into two, however, both its N-terminal (1-56; termed NP) and C-terminal (58-118; termed PC) halves were able to enhance expression of the reporter gene. When the NP region was further divided into NP(5-30) and NP(30-56), both regions still retained activating ability. These results suggest that the P region of HBP-1a(17) is composed of several modules each having activating function, and modification and/or conformational changes of the P region might influence its function.
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PMID:Dissection of the wheat transcription factor HBP-1a(17) reveals a modular structure for the activation domain. 906 88

The type I element (CCACGTCANCGATCCGCG), consisting of the Hex motif (CCACGTCA) and the reverse-oriented Oct motif (GATCCGCG), is necessary and sufficient to confer the S phase-specific transcription of the wheat histone H3 (TH012) gene. The transcriptional regulation via the type I element is thought to occur through interactions between transcription factors which bind specifically to the Hex and Oct motifs. Here we report S phase-specific DNA-binding proteins interacting with the type I element in partially synchronized wheat cultured cells. Hex motif-binding proteins found here resembled HBP-1a, as reported previously in terms of DNA-binding specificity. DNA-binding activities of the HBP-1a-like proteins were modulated by phosphorylation/dephosphorylation. In the electrophoretic mobility shift assay of the wheat nuclear extract, we also found three Oct motif-specific binding proteins, named OBRF (octamer-binding regulatory factor)-1, -2 and -3. One of the HBP-1a-like proteins and OBRF-1 appeared predominantly at the S phase. Thus, it was supposed that these two factors play a crucial role in the S phase-specific regulation of wheat histone gene expression.
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PMID:S phase-specific DNA-binding proteins interacting with the Hex and Oct motifs in type I element of the wheat histone H3 promoter. 1067 46


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