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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using a synthetic peptide that encompasses the zinc finger domain of the eukaryotic transcription factor Sp1, we produced a number of monoclonal antibodies that specifically reacted with the target antigen. Analysis by competitive inhibition assay of five of the monoclonal antibodies revealed that they all recognized a dominant epitope in the synthetic peptide and reacted strongly to recombinantly synthesized beta-galactosidase-Sp1 fusion polypeptide. To determine cellular distribution of Sp1-like molecules, cytoplasmic and nuclear proteins from human lung fibroblasts (HFL-1) and a human rhabdomyosarcoma cell line (A204) were immunoblotted and reacted with our antibodies. In addition to the well characterized 95 Kd and 105 Kd proteins, considered to be the authentic Sp1 polypeptide, a number of other cellular proteins reacted with these antibodies. Immunofluorescence staining of the cells with mAb to the zinc finger of Sp1 also revealed cell-specific differences in intracellular distribution of Sp1-like molecules. Both cytoplasmic and nuclear staining was readily observed in the rhabdomyosarcoma cells. In contrast, while some HFL-1 cells exhibited staining of only cytoplasm, both cytoplasmic and nuclear immunofluorescence was seen in others.
Mol Cell Biochem 1991 Feb 27
PMID:Generation of monoclonal antibodies to the zinc finger domain of the eukaryotic transcription factor Sp1. 201 Nov 20

The epsilon-globin gene is the first of the human beta-like globin genes to be expressed during development. We have analyzed protein-DNA interactions in the epsilon-globin promoter region by DNase I footprinting and electrophoretic mobility shift experiments using nuclear extracts from K562 human erythroid cells and from nonerythroid HeLa cells. A restricted set of ubiquitous proteins, including Sp1, bound to regions of the promoter including the CACCC and CCAAT sites. Three interactions, at positions -213, -165, and +3 relative to the transcription start site, were erythroid specific and corresponded to binding of GATA-1, a transcription factor highly restricted to the erythroid lineage. Interestingly, the GATA-1 site at -165 has been conserved in the promoters of 10 mammalian embryonic globin genes. Point mutations demonstrate that GATA-1 binding to this site is necessary for interaction with an erythroid-specific enhancer but that in the absence of an enhancer, GATA-1 does not increase transcription.
Mol Cell Biol 1991 May
PMID:Transcriptional role of a conserved GATA-1 site in the human epsilon-globin gene promoter. 201 65

Epidermal growth factor (EGF) and transforming growth factor alpha are important determinants of mucosal integrity in the gastrointestinal tract, and they act both directly and indirectly to prevent ulceration in the stomach. Consistent with this physiological role, EGF stimulates transcription of gastrin, a peptide hormone which regulates gastric acid secretion and mucosal growth. EGF stimulation of gastrin transcription is mediated by a GC-rich gastrin EGF response element (gERE) (GGGGCGGGGTGGGGGG) which lies between -54 and -68 in the human gastrin promoter. The gERE sequence also confers weaker responsiveness to phorbol ester stimulation. The gERE sequence differs from previously described EGF response elements. The gERE DNA sequence specifically interacts with a GH4 DNA-binding protein distinct from previously described transcription factors (Egr-1 and AP2) which bind GC-rich sequences and mediate transcriptional activation by growth factors. Furthermore, the gERE element does not bind the Sp1 transcription factor even though the gERE sequence contains a high-affinity Sp1-binding site (GGCGGG).
Mol Cell Biol 1991 May
PMID:A GC-rich element confers epidermal growth factor responsiveness to transcription from the gastrin promoter. 201 73

Previous studies have demonstrated that the mouse c-Harvey ras proto-oncogene (c-Ha-ras) promoter sequences are GC rich and contain several potential transcription factor SP1 binding sites. We investigated the endonuclease hypersensitivity of this region in nuclei in vitro and whole mouse tissues in vivo and identified a very strong, ubiquitous hypersensitive site covering the proximal promoter sequences. Footprint protection studies using nuclear extracts from various cell types including fibroblasts, erythroid cells, and both normal and transformed epithelial cells revealed a consistent protein-binding pattern. Five protein binding sites were observed, four of which correlated with potential SP1 binding sites. Competition experiments using an oligonucleotide corresponding to a consensus SP1 binding site confirmed that these sequences were indeed bound by the SP1 (or SP1-like) trans-acting factor. In addition, no differences were observed between the footprint patterns obtained using extracts from cells of different lineages or between normal and transformed epithelial cells carrying activated ras genes. The controlling elements responsible for differential c-Ha-ras transcription between cell types or at different stages of carcinogenesis therefore probably lie in other regions of the gene.
Mol Carcinog 1991
PMID:Structural analysis of the mouse c-Ha-ras gene promoter. 204 51

The collagen alpha 1(I) promoter, which is efficiently transcribed in NIH 3T3 fibroblasts, contains four binding sites for trans-acting factors, as demonstrated by DNase I protection assays (D. A. Brenner, R. A. Rippe, and L. Veloz, Nucleic Acids Res. 17:6055-6064, 1989). This study characterizes the DNA-binding proteins that interact with the two proximal footprinted regions, both of which contain a reverse CCAAT box and a G + C-rich 12-bp direct repeat. Analysis by DNase I protection assays, mobility shift assays, competition with specific oligonucleotides, binding with recombinant proteins, and reactions with specific antisera showed that the transcriptional factors nuclear factor I (NF-I) and Sp1 bind to these two footprinted regions. Because of overlapping binding sites, NF-I binding and Sp1 binding appear to be mutually exclusive. Overexpression of NF-I in cotransfection experiments with the alpha 1(I) promoter in NIH 3T3 fibroblasts increased alpha 1(I) expression, while Sp1 overexpression reduced this effect, as well as basal promoter activity. The herpes simplex virus thymidine kinase promoter, which contains independent NF-I- and Sp1-binding sites, was stimulated by both factors. Therefore, expression of the collagen alpha 1(I) gene may depend on the relative activities of NF-I and Sp1.
Mol Cell Biol 1991 Aug
PMID:Transcription factors nuclear factor I and Sp1 interact with the murine collagen alpha 1 (I) promoter. 207 9

Maize streak virus (MSV) is transcribed bidirectionally from an intergenic region and rightward transcription produces an RNA that encodes the coat protein. The intergenic region contains promoter elements required for rightward transcription including an upstream activating sequence (UAS) which endows the promoter with full activity in a maize transient expression system. The UAS contains two GC-rich repeats (GC boxes) and a long inverted repeat or hairpin with a loop harboring a TAATATTAC sequence common to all geminiviruses. Deletions through the UAS demonstrated the presence of an element, called the rightward promoter element (rpe1), which is responsible for transcriptional activation. Rpe1 includes the two GC-rich boxes, which are similar in sequence to Sp1 binding sites in mammalian cells, but not the conserved hairpin loop. Rpe1 binds maize nuclear factors in vitro and the characteristics of the binding interaction have been determined by 1) binding competition with oligonucleotides, 2) methidiumpropyl-EDTA footprinting and 3) methylation interference assays. Binding of maize nuclear factors to the UAS generates two major bands, slow and fast migrating bands, in gel retardation assays. Footprinting and factor titration data suggest that the fast bands arise by the binding of factors to one GC box while the slow bands are generated by factors binding to both boxes. The data further indicate that the factors bind to the two GC-rich boxes with little cooperativity and bind on opposite faces of the DNA helix.
Plant Mol Biol 1990 Dec
PMID:The intergenic region of maize streak virus contains a GC-rich element that activates rightward transcription and binds maize nuclear factors. 210 78

The mouse gene Krox-24 is transiently activated during cell cycle reentry. It encodes a protein with three zinc fingers similar to those of the transcription factor Sp1. Here we present a biochemical characterization of the gene products. Krox-24 mRNA is translated into two proteins of 82 and 88 kilodaltons, designated p82Krox-24 and p88Krox-24, respectively. p82Krox-24 is initiated at the first AUG codon of the open reading frame, whereas synthesis of p88Krox-24 starts at a non-AUG codon located upstream. Both proteins were synthesized in HeLa cells infected with recombinant vaccinia viruses expressing Krox-24 cDNAs. Under these conditions, they were found phosphorylated on serine residues and glycosylated. The availability of the proteins made possible the determination of the DNA recognition sequence. In vitro, Krox-24 bound specifically to the sequence 5'-GCG(C/G)GGGCG-3'. This sequence is similar but not identical to the Sp1 target sequence. Insertion of an oligomer for the binding site in cis, close to the herpes simplex virus thymidine kinase promoter, rendered this promoter responsive to Krox-24. Krox-24 is therefore a sequence-specific transcriptional activator. Krox-24-binding sites were found upstream of several serum-inducible genes, raising the possibility that Krox-24 is involved in the regulation of these genes.
Mol Cell Biol 1990 Jul
PMID:The serum-inducible mouse gene Krox-24 encodes a sequence-specific transcriptional activator. 211 74

The invariant chain (Ii) is a glycoprotein coexpressed with the major histocompatibility complex (MHC) class II antigens. Although Ii is encoded by a single gene unlinked to the MHC gene complex, Ii and MHC class II appear to have similar patterns of tissue specific expression and generally are coordinately regulated by cytokines. Here we present evidence that transcription of the murine Ii gene is controlled by multiple cis-acting elements. The 5' regulatory region of the Ii gene appears to be combined of conserved class II regulatory elements with promoter elements commonly found in other eucaryotic genes. A region containing characteristic class II promoter elements (H box, X box, and a modified Y box) serves as an upstream enhancer in the Ii gene and might contribute to the coexpression of MHC class II and Ii genes. A series of positive control elements, the kappa B element, Sp1-binding site, and CCAAT box, are present in the Ii promoter and apparently serve distinct regulatory functions. The kappa B site in the Ii gene is a cell type-specific element, contributing to expression in a B-cell line but not in a fibroblast cell line, and the Sp1 site is required by the H-X-Y' enhancer element to stimulate promoter activity. In addition, an Ii enhancer in the first intron that specifically stimulates its own promoter has been identified. Our results suggest that a sequence match between enhancers and certain promoter elements is critical.
Mol Cell Biol 1990 Aug
PMID:Transcriptional control of the invariant chain gene involves promoter and enhancer elements common to and distinct from major histocompatibility complex class II genes. 211 16

A 2.4-kb rat neu genomic DNA fragment that hybridized to the 5'-most coding sequence of the rat neu cDNA was cloned. S1 nuclease mapping identified multiple transcriptional initiation sites. DNA sequence analysis revealed that this fragment contained 64 bp of the first intron, 81 bp of the first exon, and the upstream noncoding sequence of the neu gene. The sequence immediately upstream of the translation start site was G + C rich (greater than 75%) and contained a consensus CCAAT sequence despite the absence of a TATA box. An Sp1-binding site was found, in addition to various sequence motifs common to the promoters of the human neu gene (erbB2), the epidermal growth factor receptor gene, and the simian virus 40 enhancer. A 2.2-kb EcoRI-Narl fragment containing sequences upstream from the 3'-most transcriptional start site was fused to the bacterial chloramphenicol acetyltransferase reporter gene and shown to promote transcription efficiently. A series of promoter deletion constructs was made, and results from transfection and subsequent chloramphenicol acetyltransferase assays suggested the presence of multiple cis-acting elements that contributed either positively or negatively to the transcription activity. Cotransfection competition experiments using subcloned cis-acting elements confirmed the existence of trans-acting factors interacting with these DNA fragments. In addition, a gel retardation assay was performed to demonstrate the physical binding of nuclear factors to certain fragments. The results complemented those of the deletion studies and led us to conclude that transcriptional regulation of the neu proto-oncogene involves at least one negative and three positive trans-acting factors interacting with different cis-acting elements along the neu gene promoter.
Mol Cell Biol 1990 Dec
PMID:Multiple cis- and trans-acting elements involved in regulation of the neu gene. 212 92

The promoter of the human gene for the alpha-subunit of Gi2, a GTP-binding signal transduction protein, was analyzed by cloning the 5' flanking region of the gene upstream of the bacterial chloramphenicol acetyltransferase (CAT) gene and measuring the level of CAT expression after transfection in CV-1 green monkey kidney cells. Analysis of multiple 5' deletion mutants reveals that a minimum of 85 bases upstream of the major transcriptional initiation site are required for full basal promoter activity. Deleting 11 bases to position -74 causes a 4-fold decrease in promoter activity. Another major decrement in activity is seen when a GC box between -46 and -33 is deleted, consistent with this region being a functionally active Sp1 factor-binding site. Primer extension of a CAT-specific primer hybridized to RNA from cells transfected with a Gi2 alpha promoter-CAT construct confirms approximately the same transcriptional start site as the endogenous Gi2 alpha gene. The 3' deletion mutants that either approach or delete the transcriptional start site have markedly diminished activity.
Mol Endocrinol 1990 Jul
PMID:Characterization of the promoter of the human Gi2 alpha-subunit gene. 212 99


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