1
|
Lin D, Ippolito GC, Zong RT, Bryant J, Koslovsky J, Tucker P. Bright/ARID3A contributes to chromatin accessibility of the immunoglobulin heavy chain enhancer. Mol Cancer 2007; 6:23. [PMID: 17386101 PMCID: PMC1852116 DOI: 10.1186/1476-4598-6-23] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 03/26/2007] [Indexed: 01/27/2023] Open
Abstract
Bright/ARID3A is a nuclear matrix-associated transcription factor that stimulates immunoglobulin heavy chain (IgH) expression and Cyclin E1/E2F-dependent cell cycle progression. Bright positively activates IgH transcriptional initiation by binding to ATC-rich P sites within nuclear matrix attachment regions (MARs) flanking the IgH intronic enhancer (Eμ). Over-expression of Bright in cultured B cells was shown to correlate with DNase hypersensitivity of Eμ. We report here further efforts to analyze Bright-mediated Eμ enhancer activation within the physiological constraints of chromatin. A system was established in which VH promoter-driven in vitro transcription on chromatin- reconstituted templates was responsive to Eμ. Bright assisted in blocking the general repression caused by nucleosome assembly but was incapable of stimulating transcription from prebound nucleosome arrays. In vitro transcriptional derepression by Bright was enhanced on templates in which Eμ is flanked by MARs and was inhibited by competition with high affinity Bright binding (P2) sites. DNase hypersensitivity of chromatin-reconstituted Eμ was increased when prepackaged with B cell nuclear extract supplemented with Bright. These results identify Bright as a contributor to accessibility of the IgH enhancer.
Collapse
Affiliation(s)
- Danjuan Lin
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Gregory C Ippolito
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Rui-Ting Zong
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - James Bryant
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Janet Koslovsky
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Philip Tucker
- Section of Molecular Genetics and Microbiology and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| |
Collapse
|
2
|
Kaul-Ghanekar R, Jalota A, Pavithra L, Tucker P, Chattopadhyay S. SMAR1 and Cux/CDP modulate chromatin and act as negative regulators of the TCRbeta enhancer (Ebeta). Nucleic Acids Res 2004; 32:4862-75. [PMID: 15371550 PMCID: PMC519105 DOI: 10.1093/nar/gkh807] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Chromatin modulation at various cis-acting elements is critical for V(D)J recombination during T and B cell development. MARbeta, a matrix-associated region (MAR) located upstream of the T cell receptor beta (TCRbeta) enhancer (Ebeta), serves a crucial role in silencing Ebeta-mediated TCR activation. By DNaseI hypersensitivity assays, we show here that overexpression of the MAR binding proteins SMAR1 and Cux/CDP modulate the chromatin structure at MARbeta. We further demonstrate that the silencer function of MARbeta is mediated independently by SMAR1 and Cux/CDP as judged by their ability to repress Ebeta-dependent reporter gene expression. Moreover, the repressor activity of SMAR1 is strongly enhanced in the presence of Cux/CDP. These two proteins physically interact with each other and colocalize within the perinuclear region through a SMAR1 domain required for repression. The repression domain of SMAR1 is separate from the MARbeta binding domain and contains a nuclear localization signal and an arginine-serine (RS)-rich domain, characteristic of pre-mRNA splicing regulators. Our data suggest that at the double positive stage of T cell development, cis-acting MARbeta elements recruit the strong negative regulators Cux and SMAR1 to control Ebeta-mediated recombination and transcription.
Collapse
|
3
|
Zhong XP, Carabaña J, Krangel MS. Flanking nuclear matrix attachment regions synergize with the T cell receptor delta enhancer to promote V(D)J recombination. Proc Natl Acad Sci U S A 1999; 96:11970-5. [PMID: 10518560 PMCID: PMC18396 DOI: 10.1073/pnas.96.21.11970] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Previous studies have identified nuclear matrix attachment regions (MARs) that are closely associated with transcriptional enhancers in the IgH, Igkappa, and T cell receptor (TCR) beta loci, but have yielded conflicting information regarding their functional significance. In this report, a combination of in vitro and in situ mapping approaches was used to localize three MARs associated with the human TCR delta gene. Two of these are located within the Jdelta3-Cdelta intron, flanking the core TCR delta enhancer (Edelta) both 5' and 3' in a fashion reminiscent of the Ig heavy chain intronic enhancer-associated MARs. The third is located about 20 kb upstream, tightly linked to Ddelta1 and Ddelta2. We have previously used a transgenic minilocus V(D)J recombination reporter to establish that Edelta functions as a developmental regulator of V(D)J recombination, and that it does so by modulating substrate accessibility to the V(D)J recombinase. We show here that the Edelta-associated MARs function synergistically with the core Edelta to promote V(D)J recombination in this system, as they are required for enhancer-dependent transgene rearrangement in single-copy transgene integrants.
Collapse
Affiliation(s)
- X P Zhong
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
| | | | | |
Collapse
|
4
|
Wang Z, Goldstein A, Zong RT, Lin D, Neufeld EJ, Scheuermann RH, Tucker PW. Cux/CDP homeoprotein is a component of NF-muNR and represses the immunoglobulin heavy chain intronic enhancer by antagonizing the bright transcription activator. Mol Cell Biol 1999; 19:284-95. [PMID: 9858552 PMCID: PMC83886 DOI: 10.1128/mcb.19.1.284] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/1998] [Accepted: 09/22/1998] [Indexed: 01/19/2023] Open
Abstract
Nuclear matrix attachment regions (MARs) flanking the immunoglobulin heavy chain intronic enhancer (Emu) are the targets of the negative regulator, NF-muNR, found in non-B and early pre-B cells. Expression library screening with NF-muNR binding sites yielded a cDNA clone encoding an alternatively spliced form of the Cux/CDP homeodomain protein. Cux/CDP fulfills criteria required for NF-muNR identity. It is expressed in non-B and early pre-B cells but not mature B cells. It binds to NF-muNR binding sites within Emu with appropriate differential affinities. Antiserum specific for Cux/CDP recognizes a polypeptide of the predicted size in affinity-purified NF-muNR preparations and binds NF-muNR complexed with DNA. Cotransfection with Cux/CDP represses the activity of Emu via the MAR sequences in both B and non-B cells. Cux/CDP antagonizes the effects of the Bright transcription activator at both the DNA binding and functional levels. We propose that Cux/CDP regulates cell-type-restricted, differentiation stage-specific Emu enhancer activity by interfering with the function of nuclear matrix-bound transcription activators.
Collapse
Affiliation(s)
- Z Wang
- Department of Pathology and Laboratory of Molecular Pathology, The University of Texas Southwestern Medical Center, Dallas, Texas 75235-9072, USA
| | | | | | | | | | | | | |
Collapse
|
5
|
Goyenechea B, Klix N, Yélamos J, Williams GT, Riddell A, Neuberger MS, Milstein C. Cells strongly expressing Ig(kappa) transgenes show clonal recruitment of hypermutation: a role for both MAR and the enhancers. EMBO J 1997; 16:3987-94. [PMID: 9233808 PMCID: PMC1170022 DOI: 10.1093/emboj/16.13.3987] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The V regions of immunoglobulin kappa transgenes are targets for hypermutation in germinal centre B cells. We show by use of modified transgenes that the recruitment of hypermutation is substantially impaired by deletion of the nuclear matrix attachment region (MAR) which flanks the intron-enhancer (Ei). Decreased mutation is also obtained if Ei, the core region of the kappa3'-enhancer (E3') or the E3'-flank are removed individually. A broad correlation between expression and mutation is indicated not only by the fact that the deletions affecting mutation also give reduced transgene expression, but especially by the finding that, within a single mouse, transgene mutation was considerably reduced in germinal centre B cells that poorly expressed the transgene as compared with strongly expressing cells. We also observed that the diminished mutation in transgenes carrying regulatory element deletions was manifested by an increased proportion of B cells in which the transgene had not been targeted at all for mutation rather than in the extent of mutation accumulation once targeted. Since mutations appear to be incorporated stepwise, the results point to a connection between transcription initiation and the clonal recruitment of hypermutation, with hypermutation being more fastidious than transcription in requiring the presence of a full complement of regulatory elements.
Collapse
Affiliation(s)
- B Goyenechea
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | | | | | | | | | | |
Collapse
|
6
|
Parolini O, Rohrer J, Shapiro LH, Conley ME. B-cell-specific demethylation of BTK, the defective gene in X-linked agammaglobulinemia. Immunogenetics 1995; 42:129-35. [PMID: 7541776 DOI: 10.1007/bf00178587] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BTK, the gene that is defective in X-linked agammaglobulinemia, encodes a cytoplasmic tyrosine kinase that is critical for B-cell proliferation, or survival. To identify regulatory elements that control the expression of BTK we evaluated the methylation pattern of this gene in cell lines and in freshly isolated cells. An Hpa II site that was specifically demethylated in mature B cells but not in pre-B cells, T cells, neutrophils, or nonhematopoietic cells was identified in the tenth intron of BTK. In a 40 kilobase (kb) segment of DNA spanning the entire coding region of BTK plus 3 kb upstream of the first exon there were no other sites that demonstrated lineage-specific demethylation. The B-cell-specific demethylation site in intron 10, which falls within the SH2 domain, 26 kb distal to the first exon, occurs in a region rich in regulatory elements including two E2 boxes, two AP-2 sites, and a cAMP response element. It is likely that this site plays a role in maintaining BTK transcription in mature B cells.
Collapse
Affiliation(s)
- O Parolini
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38101, USA
| | | | | | | |
Collapse
|
7
|
Abstract
We have identified a new immunoglobulin heavy-chain enhancer element, designated pi, between the microE2 and microE3 elements. The pi enhancer element is transcriptionally active primarily during early stages of B-cell development but becomes virtually inactive during B-cell maturation at about the stage of immunoglobulin kappa light-chain gene rearrangement. Mutational analysis suggests that the pi element is crucial for immunoglobulin heavy-chain enhancer activity at the pre-B-cell stage but is almost irrelevant for enhancer activity at the mature B-cell or plasma-cell stage. The activity of the pi enhancer element correlates with the presence of an apparently pre-B-cell-specific protein-DNA complex. The similarity of the pi site to recognition sequences for members of the ets gene family suggests that the protein(s) interacting with the pi site most likely are ets-related transcription factors.
Collapse
|
8
|
Libermann TA, Baltimore D. Pi, a pre-B-cell-specific enhancer element in the immunoglobulin heavy-chain enhancer. Mol Cell Biol 1993; 13:5957-69. [PMID: 8413200 PMCID: PMC364640 DOI: 10.1128/mcb.13.10.5957-5969.1993] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We have identified a new immunoglobulin heavy-chain enhancer element, designated pi, between the microE2 and microE3 elements. The pi enhancer element is transcriptionally active primarily during early stages of B-cell development but becomes virtually inactive during B-cell maturation at about the stage of immunoglobulin kappa light-chain gene rearrangement. Mutational analysis suggests that the pi element is crucial for immunoglobulin heavy-chain enhancer activity at the pre-B-cell stage but is almost irrelevant for enhancer activity at the mature B-cell or plasma-cell stage. The activity of the pi enhancer element correlates with the presence of an apparently pre-B-cell-specific protein-DNA complex. The similarity of the pi site to recognition sequences for members of the ets gene family suggests that the protein(s) interacting with the pi site most likely are ets-related transcription factors.
Collapse
Affiliation(s)
- T A Libermann
- Department of Medicine, Beth Israel Hospital, Boston, Massachusetts 02215
| | | |
Collapse
|
9
|
Sukovich DA, Shabbeer J, Periasamy M. Analysis of the rabbit cardiac/slow twitch muscle sarcoplasmic reticulum calcium ATPase (SERCA2) gene promoter. Nucleic Acids Res 1993; 21:2723-8. [PMID: 8332469 PMCID: PMC309608 DOI: 10.1093/nar/21.11.2723] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The rabbit cardiac/slow twitch muscle sarcoplasmic reticulum (SR) Ca2+ ATPase (SERCA2) gene encodes a Ca2+ transport pump whose expression is regulated during skeletal/cardiac muscle development and by different pathophysiological states of the heart. This study was designed to delineate cis-acting regulatory elements involved in SERCA2 gene expression. A series of unidirectionally deleted fragments of the upstream 1,460 bp SERCA2 promoter were linked to the chloramphenicol acetyltransferase (CAT) reporter gene. Transient DNA transfection experiments performed with these constructs in C2C12 muscle cells and NIH3T3 fibroblasts revealed a 17 bp upstream promoter element (UPE) important for transcription of the SERCA2 gene in skeletal muscle cells. These studies have also identified a strong (muscle specific) negative regulatory region located upstream of nucleotide -658. Gel mobility shift and southwestern analyses using the 17 bp UPE have revealed a specific DNA binding complex referred to as Ca2+ ATPase promoter factor -1 (CaPF1). The binding factor has an approximate M(r) of 43 kDa. Comparison of CaPF1 with known transcription factors suggests that the CaPF1 complex may be a novel DNA-binding transcription factor which plays a role in SERCA2 gene regulation in vivo.
Collapse
Affiliation(s)
- D A Sukovich
- Department of Physiology and Biophysics, University of Vermont, College of Medicine, Burlington 05405
| | | | | |
Collapse
|
10
|
Drosophila transcriptional repressor protein that binds specifically to negative control elements in fat body enhancers. Mol Cell Biol 1992. [PMID: 1508206 DOI: 10.1128/mcb.12.9.4093] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of the Drosophila melanogaster Adh gene in adults requires a fat body-specific enhancer called the Adh adult enhancer (AAE). We have identified a protein in Drosophila nuclear extracts that binds specifically to a site within the AAE (adult enhancer factor 1 [AEF-1]). In addition, we have shown that AEF-1 binds specifically to two other Drosophila fat body enhancers. Base substitutions in the AEF-1 binding site that disrupt AEF-1 binding in vitro result in a significant increase in the level of Adh expression in vivo. Thus, the AEF-1 binding site is a negative regulatory element within the AAE. A cDNA encoding the AEF-1 protein was isolated and shown to act as a repressor of the AAE in cotransfection studies. The AEF-1 protein contains four zinc fingers and an alanine-rich sequence. The latter motif is found in other eukaryotic proteins known to be transcriptional repressors.
Collapse
|
11
|
Falb D, Maniatis T. Drosophila transcriptional repressor protein that binds specifically to negative control elements in fat body enhancers. Mol Cell Biol 1992; 12:4093-103. [PMID: 1508206 PMCID: PMC360306 DOI: 10.1128/mcb.12.9.4093-4103.1992] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Expression of the Drosophila melanogaster Adh gene in adults requires a fat body-specific enhancer called the Adh adult enhancer (AAE). We have identified a protein in Drosophila nuclear extracts that binds specifically to a site within the AAE (adult enhancer factor 1 [AEF-1]). In addition, we have shown that AEF-1 binds specifically to two other Drosophila fat body enhancers. Base substitutions in the AEF-1 binding site that disrupt AEF-1 binding in vitro result in a significant increase in the level of Adh expression in vivo. Thus, the AEF-1 binding site is a negative regulatory element within the AAE. A cDNA encoding the AEF-1 protein was isolated and shown to act as a repressor of the AAE in cotransfection studies. The AEF-1 protein contains four zinc fingers and an alanine-rich sequence. The latter motif is found in other eukaryotic proteins known to be transcriptional repressors.
Collapse
Affiliation(s)
- D Falb
- Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138
| | | |
Collapse
|
12
|
Simkevich CP, Thompson JP, Poppleton H, Raghow R. The transcriptional tissue specificity of the human pro alpha 1 (I) collagen gene is determined by a negative cis-regulatory element in the promoter. Biochem J 1992; 286 ( Pt 1):179-85. [PMID: 1520267 PMCID: PMC1133036 DOI: 10.1042/bj2860179] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The transcriptional activity of plasmid pCOL-KT, in which human pro alpha 1 (I) collagen gene upstream sequences up to -804 and most of the first intron (+474 to +1440) drive expression of the chloramphenicol acetyltransferase (CAT) gene [Thompson, Simkevich, Holness, Kang & Raghow (1991) J. Biol. Chem. 266, 2549-2556], was tested in a number of mesenchymal and non-mesenchymal cells. We observed that pCOL-KT was readily expressed in fibroblasts of human (IMR-90 and HFL-1), murine (NIH 3T3) and avian (SL-29) origin and in a human rhabdomyosarcoma cell line (A204), but failed to be expressed in human erythroleukaemia (K562) and rat pheochromocytoma (PC12) cells, indicating that the regulatory elements required for appropriate tissue-specific expression of the human pro alpha 1 (I) collagen gene were present in pCOL-KT. To delineate the nature of cis-acting sequences which determine the tissue specificity of pro alpha 1 (I) collagen gene expression, functional consequences of deletions in the promoter and first intron of pCOL-KT were tested in various cell types by transient expression assays. Cis elements in the promoter-proximal and intronic sequences displayed either a positive or a negative influence depending on the cell type. Thus deletion of fragments using EcoRV (nt -625 to -442 deleted), XbaI (-804 to -331) or SstII (+670 to +1440) resulted in 2-10-fold decreased expression in A204 and HFL-1 cells. The negative influences of deletions in the promoter-proximal sequences was apparently considerably relieved by deleting sequences in the first intron, and the constructs containing the EcoRV/SstII or XbaI/SstII double deletions were expressed to a much greater extent than either of the single deletion constructs. In contrast, the XbaI* deletion (nt -804 to -609), either alone or in combination with the intronic deletion, resulted in very high expression in all cells regardless of their collagen phenotype; the XbaI*/(-SstII) construct, which contained the intronic SstII fragment (+670 to +1440) in the reverse orientation, was not expressed in either mesenchymal or nonmesenchymal cells. Based on these results, we conclude that orientation-dependent interactions between negatively acting 5'-upstream sequences and the first intron determine the mesenchymal cell specificity of human pro alpha 1 (I) collagen gene transcription.
Collapse
Affiliation(s)
- C P Simkevich
- Department of Pharmacology, University of Tennessee, Memphis
| | | | | | | |
Collapse
|
13
|
Abstract
For an understanding of the molecular basis of the marked decrease in catalase activity of various tumor cells, expression of the catalase gene was studied in rat and human hepatoma cell lines and in rat liver, which was used as a control with high activity. RNA blot hybridization profiles and run-on assays indicated that the decrease in catalase activity was due to depression of catalase gene transcription. Chloramphenicol acetyltransferase (CAT) assays for the fragments with various lengths of the 5'-flanking region (up to -4.5 kb from the ATG codon) of the catalase gene revealed the presence of several cis-acting elements involved in the negative regulation of transcription. The most-upstream element with the strongest activity (-3504 to -3364 bp), when linked to the catalase promoter region (-126 bp) of the CAT construct and subjected to an in vitro transcription assay, did not yield transcripts in experiments with the hepatoma nuclear extract, whereas the unlinked template did yield transcripts. A gel shift competition assay using hepatoma nuclear extract showed the core sequence of the silencer element to be 5'-TGGGGGGAG-3'. A homology search found that the same core sequence was also present in 5'-flanking regions of the albumin gene and of some other liver enzyme genes, the expression of which has been reported to be down regulated in some hepatoma cells. Southwestern (DNA-protein) analysis demonstrated that an approximately 35-kDa nuclear protein bound to the silencer element was present in hepatoma cells but not in rat liver cells.
Collapse
|
14
|
Sato K, Ito K, Kohara H, Yamaguchi Y, Adachi K, Endo H. Negative regulation of catalase gene expression in hepatoma cells. Mol Cell Biol 1992; 12:2525-33. [PMID: 1588955 PMCID: PMC364445 DOI: 10.1128/mcb.12.6.2525-2533.1992] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
For an understanding of the molecular basis of the marked decrease in catalase activity of various tumor cells, expression of the catalase gene was studied in rat and human hepatoma cell lines and in rat liver, which was used as a control with high activity. RNA blot hybridization profiles and run-on assays indicated that the decrease in catalase activity was due to depression of catalase gene transcription. Chloramphenicol acetyltransferase (CAT) assays for the fragments with various lengths of the 5'-flanking region (up to -4.5 kb from the ATG codon) of the catalase gene revealed the presence of several cis-acting elements involved in the negative regulation of transcription. The most-upstream element with the strongest activity (-3504 to -3364 bp), when linked to the catalase promoter region (-126 bp) of the CAT construct and subjected to an in vitro transcription assay, did not yield transcripts in experiments with the hepatoma nuclear extract, whereas the unlinked template did yield transcripts. A gel shift competition assay using hepatoma nuclear extract showed the core sequence of the silencer element to be 5'-TGGGGGGAG-3'. A homology search found that the same core sequence was also present in 5'-flanking regions of the albumin gene and of some other liver enzyme genes, the expression of which has been reported to be down regulated in some hepatoma cells. Southwestern (DNA-protein) analysis demonstrated that an approximately 35-kDa nuclear protein bound to the silencer element was present in hepatoma cells but not in rat liver cells.
Collapse
Affiliation(s)
- K Sato
- Department of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, Yonago, Japan
| | | | | | | | | | | |
Collapse
|
15
|
Ritchie ME, Trask RV, Fontanet HL, Billadello JJ. Multiple positive and negative elements regulate human brain creatine kinase gene expression. Nucleic Acids Res 1991; 19:6231-40. [PMID: 1956783 PMCID: PMC329132 DOI: 10.1093/nar/19.22.6231] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We characterized the developmental expression of the brain creatine kinase (BCK) gene in the C2C12 myogenic cell line with the use of isoenzyme, Western blot, and Northern blot analyses. The results show that both BCK subunit protein and mRNA are upregulated early in myogenesis, and then downregulated in fully differentiated myotubes. To characterize the transcriptional regulatory mechanisms, a chimeric construct containing 1.2 kilobase pairs of 5'-flanking DNA from the human BCK gene placed upstream of the chloramphenicol acetyltransferase gene in the promoterless plasmid pSVOCAT was transiently transfected into C2C12 cells. In myoblasts and differentiating myotubes, the time course of expression of the constructs paralleled that of endogenous BCK mRNA. Additional constructs prepared by deleting 5'-flanking DNA were also transfected into C2C12 cells. All constructs were preferentially expressed in myoblasts relative to myotubes with absolute levels of expression increasing with deletion of 5'-flanking DNA. In nonmyogenic cells expression of the plasmids also increased with deletion of 5'-flanking DNA. An element from -1150 to -388 was isolated and found to be capable of suppressing expression of the BCK promoter and of heterologous promoters independent of orientation and position and hence to function as a silencer. Thus, BCK expression is mediated by sequences contained in the 5'-flanking DNA, including negative elements active in both C2C12 cells and nonmyogenic cells and elements that mediate the developmental expression of the BCK gene in C2C12 myogenic cells.
Collapse
Affiliation(s)
- M E Ritchie
- Cardiovascular Division, Washington University School of Medicine, St Louis, MO 63110
| | | | | | | |
Collapse
|
16
|
Identification of a matrix-associated region 5' of an immunoglobulin heavy chain variable region gene. Mol Cell Biol 1991. [PMID: 1922040 DOI: 10.1128/mcb.11.10.5206] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the accompanying report (C. F. Webb, C. Das, S. Eaton, K. Calame, and P. Tucker, Mol. Cell. Biol. 11:5197-5205, 1991), we characterize B-cell-specific protein-DNA interactions at -500 and -200 bp upstream of the mu immunoglobulin heavy chain promoter whose abundances were increased by interleukin-5 plus antigen. Because of the high A + T/G + C ratio of these sequences and the consistent findings by others that enhancer- and promoterlike regions are often located near matrix-associated regions, we asked whether these sequences might also be involved in binding to the nuclear matrix. Indeed, DNA fragments containing the -500 binding site were bound by nuclear matrix proteins. Furthermore, UV cross-linking studies showed that the DNA binding site for interleukin-5-plus-antigen-inducible proteins could also bind to proteins solubilized from the nuclear matrix. Nuclear matrix-associated sequences have also been demonstrated on either side of the intronic immunoglobulin heavy chain enhancer. Our data suggest a topological model by which interactions among proteins bound to the promoter and distal enhancer sequences might occur.
Collapse
|
17
|
Novel protein-DNA interactions associated with increased immunoglobulin transcription in response to antigen plus interleukin-5. Mol Cell Biol 1991. [PMID: 1922039 DOI: 10.1128/mcb.11.10.5197] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although much has been learned about basal levels of immunoglobulin (Ig) transcription, the regulatory effects of cytokines and antigen (Ag) upon Ig expression in lymphocytes have not been fully characterized. We previously reported that Ag plus interleukin-5 (IL-5) caused increased steady-state Ig mRNA levels in Ag-specific cell lines. In this study, we have identified a region between -250 and -125 bp 5' of the Ig transcription start site that is necessary for the induction of increased mu mRNA levels by Ag plus IL-5. Mobility shift and UV cross-linking studies indicated that IL-5 plus Ag induced increased protein binding to this region. Furthermore, this sequence was found to be closely related to another A + T-rich sequence at -525 bp 5' of the transcription start site. Both sequences exhibited similar B-cell-specific and inducible protein binding. Our data suggest that treatment with IL-5 plus Ag induces several DNA-binding proteins, some of which may participate in increasing Ig transcription above basal levels by binding to sequences 5' of the octamer motif.
Collapse
|
18
|
Webb CF, Das C, Eneff KL, Tucker PW. Identification of a matrix-associated region 5' of an immunoglobulin heavy chain variable region gene. Mol Cell Biol 1991; 11:5206-11. [PMID: 1922040 PMCID: PMC361557 DOI: 10.1128/mcb.11.10.5206-5211.1991] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In the accompanying report (C. F. Webb, C. Das, S. Eaton, K. Calame, and P. Tucker, Mol. Cell. Biol. 11:5197-5205, 1991), we characterize B-cell-specific protein-DNA interactions at -500 and -200 bp upstream of the mu immunoglobulin heavy chain promoter whose abundances were increased by interleukin-5 plus antigen. Because of the high A + T/G + C ratio of these sequences and the consistent findings by others that enhancer- and promoterlike regions are often located near matrix-associated regions, we asked whether these sequences might also be involved in binding to the nuclear matrix. Indeed, DNA fragments containing the -500 binding site were bound by nuclear matrix proteins. Furthermore, UV cross-linking studies showed that the DNA binding site for interleukin-5-plus-antigen-inducible proteins could also bind to proteins solubilized from the nuclear matrix. Nuclear matrix-associated sequences have also been demonstrated on either side of the intronic immunoglobulin heavy chain enhancer. Our data suggest a topological model by which interactions among proteins bound to the promoter and distal enhancer sequences might occur.
Collapse
Affiliation(s)
- C F Webb
- Department of Immunobiology, Oklahoma Medical Research Foundation, Oklahoma City 73104
| | | | | | | |
Collapse
|
19
|
Webb CF, Das C, Eaton S, Calame K, Tucker PW. Novel protein-DNA interactions associated with increased immunoglobulin transcription in response to antigen plus interleukin-5. Mol Cell Biol 1991; 11:5197-205. [PMID: 1922039 PMCID: PMC361554 DOI: 10.1128/mcb.11.10.5197-5205.1991] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Although much has been learned about basal levels of immunoglobulin (Ig) transcription, the regulatory effects of cytokines and antigen (Ag) upon Ig expression in lymphocytes have not been fully characterized. We previously reported that Ag plus interleukin-5 (IL-5) caused increased steady-state Ig mRNA levels in Ag-specific cell lines. In this study, we have identified a region between -250 and -125 bp 5' of the Ig transcription start site that is necessary for the induction of increased mu mRNA levels by Ag plus IL-5. Mobility shift and UV cross-linking studies indicated that IL-5 plus Ag induced increased protein binding to this region. Furthermore, this sequence was found to be closely related to another A + T-rich sequence at -525 bp 5' of the transcription start site. Both sequences exhibited similar B-cell-specific and inducible protein binding. Our data suggest that treatment with IL-5 plus Ag induces several DNA-binding proteins, some of which may participate in increasing Ig transcription above basal levels by binding to sequences 5' of the octamer motif.
Collapse
Affiliation(s)
- C F Webb
- Department of Immunobiology, Oklahoma Medical Research Foundation, Oklahoma City 73104
| | | | | | | | | |
Collapse
|
20
|
Chapman BS, Thayer RM, Vincent KA, Haigwood NL. Effect of intron A from human cytomegalovirus (Towne) immediate-early gene on heterologous expression in mammalian cells. Nucleic Acids Res 1991; 19:3979-86. [PMID: 1650459 PMCID: PMC328492 DOI: 10.1093/nar/19.14.3979] [Citation(s) in RCA: 240] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A 2.4 kb fragment of hCMV (Towne strain), containing the 5' end of the major immediate-early gene, has been cloned, sequenced, and used to construct a series of mammalian cell expression plasmids. The effects of regulatory regions present on this fragment were assessed using human glycoproteins as reporter molecules. We compared secreted levels of Factor VIII, t-PA, and HIV-1 envelope glycoproteins in cells transfected with plasmids in which intron A of the immediate-early gene was present or absent. Secretion of several glycoproteins was significantly higher when cells were transfected with intron A-containing plasmids. Mutation of three basepairs in the strong nuclear factor 1 (NF1) binding site in intron A led to reduced transient expression levels, but not to the level observed in the absence of intron A. Reduced expression from NF1 mutant plasmids was roughly correlated with reduced binding in vitro of NF1 proteins to a synthetic oligonucleotide containing the mutation. The evidence indicates that sequences in intron A positively regulate expression from the hCMV immediate-early enhancer/promoter in transformed monkey kidney cells.
Collapse
Affiliation(s)
- B S Chapman
- Product Management and Regulatory Affairs, Chiron Corporation, Emeryville, CA 94608
| | | | | | | |
Collapse
|
21
|
Abstract
Although the activating factor NF-kappa B can be present in the nucleus of many cell types, transcription and rearrangement of the immunoglobulin kappa chain gene is restricted to cells of the B lineage. Part of this specificity is determined by sequences within the major intron of the kappa gene that specifically silence gene expression in non-B cells (T cells and HeLa cells). These sequences are found in a 232-bp fragment located 5' of the NF-kappa B binding sequence of the enhancer. When this fragment is added back upstream of an active NF-kappa B site, it specifically decreases the expression of a linked gene by more than 10-fold in activated T cells but it has no effect on expression in B cells. The kappa silencer region acts in an orientation- and distance-independent manner and appears to be composed of multiple negative elements. The kappa silencer may act to restrict transcription and rearrangement of the C kappa locus to cells of the B lineage.
Collapse
|
22
|
Pierce JW, Gifford AM, Baltimore D. Silencing of the expression of the immunoglobulin kappa gene in non-B cells. Mol Cell Biol 1991; 11:1431-7. [PMID: 1899907 PMCID: PMC369419 DOI: 10.1128/mcb.11.3.1431-1437.1991] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Although the activating factor NF-kappa B can be present in the nucleus of many cell types, transcription and rearrangement of the immunoglobulin kappa chain gene is restricted to cells of the B lineage. Part of this specificity is determined by sequences within the major intron of the kappa gene that specifically silence gene expression in non-B cells (T cells and HeLa cells). These sequences are found in a 232-bp fragment located 5' of the NF-kappa B binding sequence of the enhancer. When this fragment is added back upstream of an active NF-kappa B site, it specifically decreases the expression of a linked gene by more than 10-fold in activated T cells but it has no effect on expression in B cells. The kappa silencer region acts in an orientation- and distance-independent manner and appears to be composed of multiple negative elements. The kappa silencer may act to restrict transcription and rearrangement of the C kappa locus to cells of the B lineage.
Collapse
Affiliation(s)
- J W Pierce
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142
| | | | | |
Collapse
|
23
|
Positive and negative regulation of immunoglobulin gene expression by a novel B-cell-specific enhancer element. Mol Cell Biol 1991. [PMID: 1986254 DOI: 10.1128/mcb.11.1.75] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A new B-cell-specific enhancer element has been identified 3' of E4 and the octamerlike motifs in the human immunoglobulin heavy-chain gene enhancer. Tandem copies of this 67-bp MnlI-AluI fragment, when fused to the chloramphenicol acetyltransferase gene driven by the conalbumin promoter, stimulated transcription in B cells but not in Jurkat T cells or HeLa cells. Footprinting analysis revealed that the identical sequence CCGAAACTGAAAAGG, designated E6, was protected by nuclear extracts from B cells, T cells, or HeLa cells. Gel mobility shift assays using a synthetic E6 motif detected a B-cell-specific complex in addition to a ubiquitous band found also in T cells and HeLa cells. In agreement with the results of gel retardation assays, tandem copies of the E6 motif stimulated transcription in ARH77 and Raji cells but not in Jurkat or HeLa cells. Furthermore, a mutant E6 motif lost both in vitro binding activity and in vivo enhancer activity. In striking contrast to the mouse Ig heavy-chain enhancer, in which the octamer motif acts as a B-cell-specific enhancer element, the human enhancer contains an octamerlike sequence with one base substitution which bound octamer-binding proteins with only very low affinity and showed no enhancer activity of its own. Interestingly, the MnlI-AluI fragment could suppress the basal-level activity of the conalbumin promoter in both Jurkat and HeLa cells. Moreover, simian virus 40 enhancer activity was blocked by the MnlI-AluI fragment in HeLa cells but not in B cells. Thus, the novel enhancer element identified in this study is probably a target site for both positive and negative factors.
Collapse
|
24
|
Positive and negative regulation of immunoglobulin gene expression by a novel B-cell-specific enhancer element. Mol Cell Biol 1991; 11:75-83. [PMID: 1986254 PMCID: PMC359591 DOI: 10.1128/mcb.11.1.75-83.1991] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A new B-cell-specific enhancer element has been identified 3' of E4 and the octamerlike motifs in the human immunoglobulin heavy-chain gene enhancer. Tandem copies of this 67-bp MnlI-AluI fragment, when fused to the chloramphenicol acetyltransferase gene driven by the conalbumin promoter, stimulated transcription in B cells but not in Jurkat T cells or HeLa cells. Footprinting analysis revealed that the identical sequence CCGAAACTGAAAAGG, designated E6, was protected by nuclear extracts from B cells, T cells, or HeLa cells. Gel mobility shift assays using a synthetic E6 motif detected a B-cell-specific complex in addition to a ubiquitous band found also in T cells and HeLa cells. In agreement with the results of gel retardation assays, tandem copies of the E6 motif stimulated transcription in ARH77 and Raji cells but not in Jurkat or HeLa cells. Furthermore, a mutant E6 motif lost both in vitro binding activity and in vivo enhancer activity. In striking contrast to the mouse Ig heavy-chain enhancer, in which the octamer motif acts as a B-cell-specific enhancer element, the human enhancer contains an octamerlike sequence with one base substitution which bound octamer-binding proteins with only very low affinity and showed no enhancer activity of its own. Interestingly, the MnlI-AluI fragment could suppress the basal-level activity of the conalbumin promoter in both Jurkat and HeLa cells. Moreover, simian virus 40 enhancer activity was blocked by the MnlI-AluI fragment in HeLa cells but not in B cells. Thus, the novel enhancer element identified in this study is probably a target site for both positive and negative factors.
Collapse
|
25
|
Negative regulation in correct tissue-specific expression of mouse mammary tumor virus in transgenic mice. Mol Cell Biol 1990. [PMID: 1700274 DOI: 10.1128/mcb.10.11.5822] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Mouse mammary tumor virus (MMTV) is an endogenous murine retrovirus that is expressed in the epithelial cells of the mammary and salivary glands, lungs, kidneys, and seminal vesicles and in the lymphoid cells of the spleen and thymus. Several studies have shown that the long terminal repeat (LTR) of this virus can direct the expression of reporter genes to the same tissues in transgenic mice. To determine whether multiple regulatory elements within the LTR are involved in this tissue-specific expression, we have established lines of transgenic mice containing transgenes that have deletions in the MMTV LTR. Deletions of all LTR sequences upstream of -364 or of LTR sequences from -165 to -665 both result in the expression of linked reporter genes such as the simian virus 40 early region or the bacterial enzyme chloramphenicol acetyltransferase in novel sites, such as the heart, brain, and skeletal muscle; expression of endogenous MMTV and transgenes containing the full-length LTR is not detected in these organs. Negative regulation appears to involve more than one region, since deletion of sequences between either -201 and -471 or -201 and -344, as well as sequences upstream of -364, results in inappropriate expression in heart, brain, and skeletal muscle. Therefore, a negative regulatory element(s) in the MMTV LTR can suppress transcription from the viral promoter in several different organs. This represents the first example of generalized negative regulatory elements that act in many different tissues in transgenic mice to prevent inappropriate expression of a gene.
Collapse
|
26
|
Ross SR, Hsu CL, Choi Y, Mok E, Dudley JP. Negative regulation in correct tissue-specific expression of mouse mammary tumor virus in transgenic mice. Mol Cell Biol 1990; 10:5822-9. [PMID: 1700274 PMCID: PMC361364 DOI: 10.1128/mcb.10.11.5822-5829.1990] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mouse mammary tumor virus (MMTV) is an endogenous murine retrovirus that is expressed in the epithelial cells of the mammary and salivary glands, lungs, kidneys, and seminal vesicles and in the lymphoid cells of the spleen and thymus. Several studies have shown that the long terminal repeat (LTR) of this virus can direct the expression of reporter genes to the same tissues in transgenic mice. To determine whether multiple regulatory elements within the LTR are involved in this tissue-specific expression, we have established lines of transgenic mice containing transgenes that have deletions in the MMTV LTR. Deletions of all LTR sequences upstream of -364 or of LTR sequences from -165 to -665 both result in the expression of linked reporter genes such as the simian virus 40 early region or the bacterial enzyme chloramphenicol acetyltransferase in novel sites, such as the heart, brain, and skeletal muscle; expression of endogenous MMTV and transgenes containing the full-length LTR is not detected in these organs. Negative regulation appears to involve more than one region, since deletion of sequences between either -201 and -471 or -201 and -344, as well as sequences upstream of -364, results in inappropriate expression in heart, brain, and skeletal muscle. Therefore, a negative regulatory element(s) in the MMTV LTR can suppress transcription from the viral promoter in several different organs. This represents the first example of generalized negative regulatory elements that act in many different tissues in transgenic mice to prevent inappropriate expression of a gene.
Collapse
Affiliation(s)
- S R Ross
- Department of Biochemistry, University of Illinois, Chicago 60612
| | | | | | | | | |
Collapse
|
27
|
The mouse albumin enhancer contains a negative regulatory element that interacts with a novel DNA-binding protein. Mol Cell Biol 1990. [PMID: 2370857 DOI: 10.1128/mcb.10.8.3896] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The far-upstream mouse albumin enhancer (-10.5 to -8.43 kilobases) has both positive and negative regulatory domains which contribute to the rate and tissue specificity of albumin gene transcription. (R. S. Herbst, N. Friedman, J. E. Darnell, Jr., and L. E. Babiss, Proc. Natl. Acad. Sci. USA 86:1553-1557). In this work, the negative regulatory region has been functionally localized to sequences -8.7 to -8.43 kilobases upstream of the albumin gene cap site. In the absence of the albumin-modulating region (in which there are binding sites for the transcription factor C/EBP), the negative region can suppress a neighboring positive-acting element, thereby interfering with albumin enhancer function. The negative region is also capable of negating the positive action of the heterologous transthyretin enhancer in an orientation-independent fashion. Within this negative-acting region we can detect two DNA-binding sites, both of which are recognized by a protein present in all cell types tested. This DNA-binding activity is not competed for by any of a series of known DNA-binding sites, and hence this new protein is a candidate for a role in suppressing the albumin gene in nonhepatic cells.
Collapse
|
28
|
Herbst RS, Boczko EM, Darnell JE, Babiss LE. The mouse albumin enhancer contains a negative regulatory element that interacts with a novel DNA-binding protein. Mol Cell Biol 1990; 10:3896-905. [PMID: 2370857 PMCID: PMC360900 DOI: 10.1128/mcb.10.8.3896-3905.1990] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The far-upstream mouse albumin enhancer (-10.5 to -8.43 kilobases) has both positive and negative regulatory domains which contribute to the rate and tissue specificity of albumin gene transcription. (R. S. Herbst, N. Friedman, J. E. Darnell, Jr., and L. E. Babiss, Proc. Natl. Acad. Sci. USA 86:1553-1557). In this work, the negative regulatory region has been functionally localized to sequences -8.7 to -8.43 kilobases upstream of the albumin gene cap site. In the absence of the albumin-modulating region (in which there are binding sites for the transcription factor C/EBP), the negative region can suppress a neighboring positive-acting element, thereby interfering with albumin enhancer function. The negative region is also capable of negating the positive action of the heterologous transthyretin enhancer in an orientation-independent fashion. Within this negative-acting region we can detect two DNA-binding sites, both of which are recognized by a protein present in all cell types tested. This DNA-binding activity is not competed for by any of a series of known DNA-binding sites, and hence this new protein is a candidate for a role in suppressing the albumin gene in nonhepatic cells.
Collapse
Affiliation(s)
- R S Herbst
- Rockefeller University, New York, New York 10021
| | | | | | | |
Collapse
|
29
|
Identification of a novel factor that interacts with an immunoglobulin heavy-chain promoter and stimulates transcription in conjunction with the lymphoid cell-specific factor OTF2. Mol Cell Biol 1990. [PMID: 2109187 DOI: 10.1128/mcb.10.5.2145] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The tissue-specific expression of the MOPC 141 immunoglobulin heavy-chain gene was studied by using in vitro transcription. B-cell-specific transcription of this gene was dependent on the octamer element 5'-ATGCAAAG-3', located in the upstream region of this promoter and in the promoters of all other immunoglobulin heavy- and light-chain genes. The interaction of purified octamer transcription factors 1 and 2 (OTF1 and OTF2) with the MOPC 141 promoter was studied by using electrophoretic mobility shift assays and DNase I footprinting. Purified OTF1 from HeLa cells and OTF1 and OTF2 from B cells bound to identical sequences within the heavy-chain promoter. The OTF interactions we observed extended over the heptamer element 5'-CTCAGGA-3', and it seems likely that the binding of the purified factors involves cooperation between octamer and heptamer sites in this promoter. In addition to these elements, we identified a second regulatory element, the N element with the sequence 5'-GGAACCTCCCCC-3'. The N element could independently mediate low levels of transcription in both B-cell and HeLa-cell extracts, and, in conjunction with the octamer element, it can promote high levels of transcription in B-cell extracts. The N element bound a transcription factor, NTF, that is ubiquitous in cell-type distribution, and NTF was distinct from any of the previously described proteins that bind to similar sequences. Based on these results, we propose that NTF and OTF2 interactions (both with their cognate DNA elements and possibly at the protein-protein level) may be critical to B-cell-specific expression and that these interactions provide additional pathways for regulating gene expression.
Collapse
|
30
|
Yoza BK, Roeder RG. Identification of a novel factor that interacts with an immunoglobulin heavy-chain promoter and stimulates transcription in conjunction with the lymphoid cell-specific factor OTF2. Mol Cell Biol 1990; 10:2145-53. [PMID: 2109187 PMCID: PMC360562 DOI: 10.1128/mcb.10.5.2145-2153.1990] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The tissue-specific expression of the MOPC 141 immunoglobulin heavy-chain gene was studied by using in vitro transcription. B-cell-specific transcription of this gene was dependent on the octamer element 5'-ATGCAAAG-3', located in the upstream region of this promoter and in the promoters of all other immunoglobulin heavy- and light-chain genes. The interaction of purified octamer transcription factors 1 and 2 (OTF1 and OTF2) with the MOPC 141 promoter was studied by using electrophoretic mobility shift assays and DNase I footprinting. Purified OTF1 from HeLa cells and OTF1 and OTF2 from B cells bound to identical sequences within the heavy-chain promoter. The OTF interactions we observed extended over the heptamer element 5'-CTCAGGA-3', and it seems likely that the binding of the purified factors involves cooperation between octamer and heptamer sites in this promoter. In addition to these elements, we identified a second regulatory element, the N element with the sequence 5'-GGAACCTCCCCC-3'. The N element could independently mediate low levels of transcription in both B-cell and HeLa-cell extracts, and, in conjunction with the octamer element, it can promote high levels of transcription in B-cell extracts. The N element bound a transcription factor, NTF, that is ubiquitous in cell-type distribution, and NTF was distinct from any of the previously described proteins that bind to similar sequences. Based on these results, we propose that NTF and OTF2 interactions (both with their cognate DNA elements and possibly at the protein-protein level) may be critical to B-cell-specific expression and that these interactions provide additional pathways for regulating gene expression.
Collapse
Affiliation(s)
- B K Yoza
- Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10021
| | | |
Collapse
|
31
|
Abstract
The immunoglobulin genes have B-cell-specific promoter and enhancer elements. The regulation of these elements is thought to be mediated to a large degree by the trans-activating factor oct-2, which binds the octamer element (ATTTGCAT). We have further examined the role of this octamer element in directing the lymphoid-specific expression of the immunoglobulin H enhancer. No direct relationship was found between the levels of expression of the Cmu gene and oct-2. Indeed, variable amounts of oct-2 were detected in all of the hemopoietic lineage cells tested in this study.
Collapse
|
32
|
Peek R, van der Logt P, Lubsen NH, Schoenmakers JG. Tissue- and species-specific promoter elements of rat gamma-crystallin genes. Nucleic Acids Res 1990; 18:1189-97. [PMID: 2320414 PMCID: PMC330434 DOI: 10.1093/nar/18.5.1189] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The 5' flanking regions of the six rat gamma-crystallin genes (gamma A-gamma F) are all capable of conferring lens-specific expression to the bacterial chloramphenicol acetyl transferase (CAT) reporter gene in either transdifferentiating chicken neural retina cells or mouse lens epithelial cells. Deletion mapping of the most active gamma-crystallin promoter region, the gamma D region, showed that at least three elements are required for maximal expression in mouse lens epithelial cells: element(s) located between -200 and -106, a conserved CG rich region around position -75, and a CG stretch around -15. The region between -200 and -106 was dispensable in transdifferentiating chicken neural retina cells, which instead required the region between -106 and -78. The maximal activity of the gamma E and gamma F promoters was also dependent upon the integrity of the conserved CG region located around -75. A synthetic oligonucleotide containing this sequence was capable of lens-specific enhancement of the activity of the tk promoter in transdifferentiating chicken neural retina cells but not in mouse lens epithelial cells. Our results further show that this region may contain a silencer element, active in non-lens tissues, as well.
Collapse
Affiliation(s)
- R Peek
- Department of Molecular Biology, University of Nijmegen, The Netherlands
| | | | | | | |
Collapse
|
33
|
Abstract
The immunoglobulin genes have B-cell-specific promoter and enhancer elements. The regulation of these elements is thought to be mediated to a large degree by the trans-activating factor oct-2, which binds the octamer element (ATTTGCAT). We have further examined the role of this octamer element in directing the lymphoid-specific expression of the immunoglobulin H enhancer. No direct relationship was found between the levels of expression of the Cmu gene and oct-2. Indeed, variable amounts of oct-2 were detected in all of the hemopoietic lineage cells tested in this study.
Collapse
Affiliation(s)
- P N Cockerill
- Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, Victoria, Australia
| | | |
Collapse
|
34
|
De Simone V, Cortese R. A negative regulatory element in the promoter of the human alpha 1-antitrypsin gene. Nucleic Acids Res 1989; 17:9407-15. [PMID: 2555792 PMCID: PMC335141 DOI: 10.1093/nar/17.22.9407] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A "minimal tissue-specific element" of the human alpha 1-antitrypsin (alpha 1-AT) gene promoter, located in the -137/-37 region, is able to drive hepatoma-specific transcription from the heterologous SV40 promoter. Here we show that, in HeLa cells, this element is inactivated by a negative regulatory mechanism. This negative control can be overcome by deletion or mutation of two specific DNA domains.
Collapse
Affiliation(s)
- V De Simone
- European Molecular Biology Laboratory (EMBL), Heidelberg, FRG
| | | |
Collapse
|
35
|
Mutagenesis of the rat insulin II 5'-flanking region defines sequences important for expression in HIT cells. Mol Cell Biol 1989. [PMID: 2657405 DOI: 10.1128/mcb.9.4.1784] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To define the cis-acting elements important for rat insulin II gene expression, we analyzed the effects of 5' deletions and linker-scanning mutations on the expression of a rat insulin II reporter gene in an insulinoma cell line (HIT). The reporter gene contained 448 base pairs of 5'-flanking sequence joined to the bacterial chloramphenicol acetyltransferase gene. Expression of the 5' deletion mutations indicated that the minimal sequence requirement for efficient expression was 218 base pairs of 5'-flanking sequence, and at least three regions downstream from - 218 were important for transcription. A more precise localization of these elements and the cis-acting sequences in the promoter was achieved by analysis of the expression of 18 linker-scanning mutations. In these studies at least four other regions important for expression of the rat insulin II gene were identified. These findings suggest that the sequences important for rat insulin II and rat insulin I expression may differ significantly despite the high degree of sequence similarity in their 5'-flanking regions.
Collapse
|
36
|
Yamaguchi M, Obata Y, Matsukage A. Paradoxical effect of Simian virus 40 enhancer on the function of mouse DNA polymerase beta gene promoter. Nucleic Acids Res 1989; 17:3725-34. [PMID: 2543952 PMCID: PMC317853 DOI: 10.1093/nar/17.10.3725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Simian virus (SV) 40 enhancer (nucleotide position 108 to 294) was combined with chloramphenicol acetyltransferase (CAT) plasmid whose expression is under control of mouse DNA polymerase beta gene promoter. Although the SV40 enhancer stimulated the transient CAT-expression directed by the DNA polymerase beta gene promoter two to three fold in human HeLa cells, it repressed the CAT-expression by 50 to 60% in mouse NIH/3T3 cells. The repression was observed relatively independently on the orientation of the insertion and the distance from the promoter. These properties of the enhancer are very similar to those of so-called transcriptional silencer element. In both HeLa and NIH/3T3 cells, the SV40 enhancer stimulated effectively its own early gene promoter-directed CAT-expression. In mouse immature T-cell line RV-1 in which the SV40 promoter-enhancer did not function, no effect of the SV40 enhancer sequence on the DNA polymerase beta promoter-directed CAT-expression was observed. Thus, it is suggested that both cell type-specific trans-acting factor(s) and the specific combination with the promoter sequence turn the properties of the SV40 enhancer into those of a silencer.
Collapse
Affiliation(s)
- M Yamaguchi
- Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Nagoya, Japan
| | | | | |
Collapse
|
37
|
Abstract
We report the discovery of a new B-lymphocyte-specific enhancer-binding protein. A series of gel retardation assays using fragments that scan the -2172 to -1180 region of the major histocompatibility complex class II gene E alpha reveal a site (W) that serves as the recognition sequence for two nuclear proteins, one B-cell restricted and the other ubiquitously occurring. Certain characteristics of the NF-W1 and NF-W2 pair recall the OTF-2/NF-A2 and OTF-1/NF-A1 pair that binds to the immunoglobulin octamer, but we demonstrate that the two protein pairs are distinguishable by several criteria. NF-W1 and NF-W2 interact differentially with their common GTTGCATC binding site, display a different affinity for it, and have molecular weights that differ by about 20,000. Yet, proteolysis experiments and cross-linking analyses indicate that the two W complexes show structural relatedness.
Collapse
|
38
|
Abstract
The major histocompatibility complex class II molecules, like the immunoglobulins, are prominent B-lymphocyte markers. Herein, we describe a B-cell-specific enhancer associated with the murine class II gene, Ek alpha. This enhancer has a complex anatomy that suggests interactions between remotely spaced elements. Of particular interest is the finding that two CCAAT boxes spaced one kilobase apart are important for enhancer activity. Somewhat surprisingly, the E alpha and immunoglobulin enhancers seem to show little resemblance.
Collapse
|
39
|
Crowe DT, Tsai MJ. Mutagenesis of the rat insulin II 5'-flanking region defines sequences important for expression in HIT cells. Mol Cell Biol 1989; 9:1784-9. [PMID: 2657405 PMCID: PMC362598 DOI: 10.1128/mcb.9.4.1784-1789.1989] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
To define the cis-acting elements important for rat insulin II gene expression, we analyzed the effects of 5' deletions and linker-scanning mutations on the expression of a rat insulin II reporter gene in an insulinoma cell line (HIT). The reporter gene contained 448 base pairs of 5'-flanking sequence joined to the bacterial chloramphenicol acetyltransferase gene. Expression of the 5' deletion mutations indicated that the minimal sequence requirement for efficient expression was 218 base pairs of 5'-flanking sequence, and at least three regions downstream from - 218 were important for transcription. A more precise localization of these elements and the cis-acting sequences in the promoter was achieved by analysis of the expression of 18 linker-scanning mutations. In these studies at least four other regions important for expression of the rat insulin II gene were identified. These findings suggest that the sequences important for rat insulin II and rat insulin I expression may differ significantly despite the high degree of sequence similarity in their 5'-flanking regions.
Collapse
Affiliation(s)
- D T Crowe
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030
| | | |
Collapse
|
40
|
Negative regulation of transcription in vitro by a glucocorticoid response element is mediated by a trans-acting factor. Mol Cell Biol 1989. [PMID: 2851730 DOI: 10.1128/mcb.8.9.3872] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In vitro experiments with cell extracts prepared from a mouse mammary epithelial cell line demonstrated that a cis-acting glucocorticoid response element (GRE) of the mouse mammary tumor virus represses transcription from its homologous promoter. Competition transcription experiments, in which a molar excess of a restriction fragment that contains the GRE is added to the cell-free assay, revealed that a nuclear factor mediates in trans the negative regulation of mammary tumor virus transcription in vitro. Gel retention assays indicated that a factor in the extracts specifically recognizes the GRE. One unusual result of the gel retention studies was that heating the GRE probe to 65 degrees C before addition to a binding assay increases the formation of the specific protein-DNA complex 20-fold. Exonuclease III footprinting demonstrated that the sequences recognized by the factor are identical for either untreated or heat-treated probe. The footprinting also demonstrated that this factor recognizes sequences that are distinct from those recognized by the glucocorticoid receptor. A synthetic oligonucleotide based on the sequences identified by the footprinting experiments repressed the activity of a heterologous enhancer-promoter in vivo, as assayed by transient expression assays. We propose that this negative transcription element may control the basal level of expression of some glucocorticoid-modulated genes and may explain the insensitivity of certain tumor cells to steroid hormone action.
Collapse
|
41
|
Negative regulation of the human polyomavirus BK enhancer involves cell-specific interaction with a nuclear repressor. Mol Cell Biol 1989. [PMID: 2850493 DOI: 10.1128/mcb.8.8.3448] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have examined the cell type-specific regulation of the human BK virus (BKV) enhancer. This enhancer functions efficiently in cis to activate expression from the adenovirus major late promoter in the human kidney cell line, 293, and in a monkey kidney cell line, MK2, but not in the HeLa cell line. In gel retardation migration assays, specific BKV enhancer-protein complexes could be observed by using nuclear extracts prepared from each cell line. Moreover, a unique DNA-protein complex was observed by using the HeLa cell nuclear extracts. By DNase footprint analysis, four binding regions for HeLa cell nuclear proteins were defined within the BKV enhancer repeat region. Two of the protected regions encompassed nuclear factor 1 or CCAAT transcription factor binding sites. These nuclear factor 1 sites also were protected by nuclear proteins from the 293 and MK2 cell lines. The other two protected sites encompassed a region of symmetry which included a sequence similar to the simian virus 40 TC enhancer motif and to a conserved sequence present upstream or within the introns of several cellular genes. These two sites were not protected by either the 293 or MK2 nuclear proteins. Competition studies in transfected cells indicated that the reduced activity of the BKV enhancer in the HeLa cell line was due to negative regulation. Further, we have demonstrated that binding of a nuclear factor(s) to the HeLa cell-specific site is involved in the repression of enhancer activity.
Collapse
|
42
|
Abstract
We report the discovery of a new B-lymphocyte-specific enhancer-binding protein. A series of gel retardation assays using fragments that scan the -2172 to -1180 region of the major histocompatibility complex class II gene E alpha reveal a site (W) that serves as the recognition sequence for two nuclear proteins, one B-cell restricted and the other ubiquitously occurring. Certain characteristics of the NF-W1 and NF-W2 pair recall the OTF-2/NF-A2 and OTF-1/NF-A1 pair that binds to the immunoglobulin octamer, but we demonstrate that the two protein pairs are distinguishable by several criteria. NF-W1 and NF-W2 interact differentially with their common GTTGCATC binding site, display a different affinity for it, and have molecular weights that differ by about 20,000. Yet, proteolysis experiments and cross-linking analyses indicate that the two W complexes show structural relatedness.
Collapse
Affiliation(s)
- A Dorn
- Laboratoire de Génétique Moléculaire des Eucaryotes, Centre National de La Recherche Scientifique, Strasbourg, France
| | | | | |
Collapse
|
43
|
Abstract
The major histocompatibility complex class II molecules, like the immunoglobulins, are prominent B-lymphocyte markers. Herein, we describe a B-cell-specific enhancer associated with the murine class II gene, Ek alpha. This enhancer has a complex anatomy that suggests interactions between remotely spaced elements. Of particular interest is the finding that two CCAAT boxes spaced one kilobase apart are important for enhancer activity. Somewhat surprisingly, the E alpha and immunoglobulin enhancers seem to show little resemblance.
Collapse
Affiliation(s)
- W Koch
- Laboratoire de Génétique Moléculaire des Eucaryotes, Centre National de la Recherche Scientifique, Strasbourg, France
| | | | | |
Collapse
|
44
|
B-cell control region at the 5' end of a major histocompatibility complex class II gene: sequences and factors. Mol Cell Biol 1988. [PMID: 3141781 DOI: 10.1128/mcb.8.10.3975] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Transcription of major histocompatibility complex class II genes is elaborately regulated. Mouse class II genes are transcribed primarily in B cells, peripheral macrophages and interdigitating cells, and thymic cortical and medullary cells. In this study, we began to identify the DNA sequences and protein factors that control expression of a class II gene in B cells, addressing in particular how closely they resemble those that regulate immunoglobulin gene expression. We describe a region upstream of the E alpha gene that is crucial for its transcription in the B cells of transgenic mice but is less important in cultured B-cell lines. The sequence of this region reveals several familiar motifs, including a second X-Y pair reminiscent of that residing in the promoter-proximal region of all class II genes, a B motif strikingly homologous to that associated with the immunoglobulin kappa gene enhancer, several Ephrussi motifs, and a Pu box-like sequence very similar to that implicated in simian virus 40 and lymphotrophic papovavirus expression in B cells. Careful study of the proteins that bind specifically to these different motifs prompts us to suggest that major histocompatibility complex class II and immunoglobulin genes rely on quite different factors to achieve B-cell-specific expression.
Collapse
|
45
|
Sakai M, Okuda A, Muramatsu M. Multiple regulatory elements and phorbol 12-O-tetradecanoate 13-acetate responsiveness of the rat placental glutathione transferase gene. Proc Natl Acad Sci U S A 1988; 85:9456-60. [PMID: 3200831 PMCID: PMC282771 DOI: 10.1073/pnas.85.24.9456] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We have analyzed the cis-acting regulatory DNA elements of the placental rat glutathione S-alkyltransferase (GST-P) gene. Various regions of the 5' flanking sequence were fused with a bacterial chloramphenicol acetyltransferase gene. The transcriptional activity of each construct was determined by the transient expression assay after introduction into a hepatoma cell line. Multiple regulatory elements were identified. Two enhancing elements were located 2.5 and 2.2 kilobases upstream from the transcription start site and designated GST-P enhancers I and II (GPEI and GPEII, respectively). A consensus sequence of the phorbol 12-O-tetradecanoate 13-acetate responsive elements was present in the GPEI and at position -61. GPEII contained two of the simian virus 40 and one of the polyoma enhancer core-like sequences. A silencing element was also found 400 base pairs upstream from the cap site. In accordance with the above observation, endogenous GST-P gene was found to be stimulated when the rat fibroblast line 3Y1 was treated with phorbol 12-O-tetradecanoate 13-acetate. Phorbol 12-O-tetradecanoate 13-acetate enhanced the expression of the transfected GST-P gene to a much higher degree in HeLa cells than in the hepatoma cells, which constitutively expressed the endogenous GST-P. The results are discussed in terms of the specific derepression of GST-P gene during hepatocarcinogenesis in the rat.
Collapse
Affiliation(s)
- M Sakai
- Department of Biochemistry, Faculty of Medicine, University of Tokyo, Japan
| | | | | |
Collapse
|
46
|
Wasylyk B, Imler JL, Chatton B, Schatz C, Wasylyk C. Negative and positive factors determine the activity of the polyoma virus enhancer alpha domain in undifferentiated and differentiated cell types. Proc Natl Acad Sci U S A 1988; 85:7952-6. [PMID: 2847148 PMCID: PMC282331 DOI: 10.1073/pnas.85.21.7952] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The host range of polyoma virus is dependent upon the activity of its enhancer, which is inactive in undifferentiated embryonal carcinoma cells, such as F9 cells, and is active after their differentiation. We show here that the activity of the alpha domain of the polyoma virus enhancer displays a similar cell-specificity and inducibility as does the whole enhancer. We present evidence to show that its activity is determined by the balance between the activities of two factors, PEA2, a labile repressor, and PEA1, an inducible positive factor that we have characterized previously. Changes in repressor activity help account for the increase in alpha-domain activity after differentiation of F9 cells. These results suggest that PEA2 is crucial in the regulation of viral gene expression and perhaps more generally in the control of gene expression during differentiation.
Collapse
Affiliation(s)
- B Wasylyk
- Laboratoire de Génétique Moléculaire des Eucaryotes, l'Institut National de la Santé et de la Recherche Medicale, Faculté de Médecine, Strasbourg, France
| | | | | | | | | |
Collapse
|
47
|
Dorn A, Fehling HJ, Koch W, Le Meur M, Gerlinger P, Benoist C, Mathis D. B-cell control region at the 5' end of a major histocompatibility complex class II gene: sequences and factors. Mol Cell Biol 1988; 8:3975-87. [PMID: 3141781 PMCID: PMC365466 DOI: 10.1128/mcb.8.10.3975-3987.1988] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Transcription of major histocompatibility complex class II genes is elaborately regulated. Mouse class II genes are transcribed primarily in B cells, peripheral macrophages and interdigitating cells, and thymic cortical and medullary cells. In this study, we began to identify the DNA sequences and protein factors that control expression of a class II gene in B cells, addressing in particular how closely they resemble those that regulate immunoglobulin gene expression. We describe a region upstream of the E alpha gene that is crucial for its transcription in the B cells of transgenic mice but is less important in cultured B-cell lines. The sequence of this region reveals several familiar motifs, including a second X-Y pair reminiscent of that residing in the promoter-proximal region of all class II genes, a B motif strikingly homologous to that associated with the immunoglobulin kappa gene enhancer, several Ephrussi motifs, and a Pu box-like sequence very similar to that implicated in simian virus 40 and lymphotrophic papovavirus expression in B cells. Careful study of the proteins that bind specifically to these different motifs prompts us to suggest that major histocompatibility complex class II and immunoglobulin genes rely on quite different factors to achieve B-cell-specific expression.
Collapse
Affiliation(s)
- A Dorn
- Laboratoire de Génétique Moléculaire des Eucaryotes, Unité 184, Faculté de Médecine, Institut de Chimie Biologique, Strasbourg, France
| | | | | | | | | | | | | |
Collapse
|
48
|
Langer SJ, Ostrowski MC. Negative regulation of transcription in vitro by a glucocorticoid response element is mediated by a trans-acting factor. Mol Cell Biol 1988; 8:3872-81. [PMID: 2851730 PMCID: PMC365446 DOI: 10.1128/mcb.8.9.3872-3881.1988] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In vitro experiments with cell extracts prepared from a mouse mammary epithelial cell line demonstrated that a cis-acting glucocorticoid response element (GRE) of the mouse mammary tumor virus represses transcription from its homologous promoter. Competition transcription experiments, in which a molar excess of a restriction fragment that contains the GRE is added to the cell-free assay, revealed that a nuclear factor mediates in trans the negative regulation of mammary tumor virus transcription in vitro. Gel retention assays indicated that a factor in the extracts specifically recognizes the GRE. One unusual result of the gel retention studies was that heating the GRE probe to 65 degrees C before addition to a binding assay increases the formation of the specific protein-DNA complex 20-fold. Exonuclease III footprinting demonstrated that the sequences recognized by the factor are identical for either untreated or heat-treated probe. The footprinting also demonstrated that this factor recognizes sequences that are distinct from those recognized by the glucocorticoid receptor. A synthetic oligonucleotide based on the sequences identified by the footprinting experiments repressed the activity of a heterologous enhancer-promoter in vivo, as assayed by transient expression assays. We propose that this negative transcription element may control the basal level of expression of some glucocorticoid-modulated genes and may explain the insensitivity of certain tumor cells to steroid hormone action.
Collapse
Affiliation(s)
- S J Langer
- Department of Microbiology and Immunology, Duke University Medical Center, Durham, North Carolina 27710
| | | |
Collapse
|
49
|
Grinnell BW, Berg DT, Walls JD. Negative regulation of the human polyomavirus BK enhancer involves cell-specific interaction with a nuclear repressor. Mol Cell Biol 1988; 8:3448-57. [PMID: 2850493 PMCID: PMC363582 DOI: 10.1128/mcb.8.8.3448-3457.1988] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We have examined the cell type-specific regulation of the human BK virus (BKV) enhancer. This enhancer functions efficiently in cis to activate expression from the adenovirus major late promoter in the human kidney cell line, 293, and in a monkey kidney cell line, MK2, but not in the HeLa cell line. In gel retardation migration assays, specific BKV enhancer-protein complexes could be observed by using nuclear extracts prepared from each cell line. Moreover, a unique DNA-protein complex was observed by using the HeLa cell nuclear extracts. By DNase footprint analysis, four binding regions for HeLa cell nuclear proteins were defined within the BKV enhancer repeat region. Two of the protected regions encompassed nuclear factor 1 or CCAAT transcription factor binding sites. These nuclear factor 1 sites also were protected by nuclear proteins from the 293 and MK2 cell lines. The other two protected sites encompassed a region of symmetry which included a sequence similar to the simian virus 40 TC enhancer motif and to a conserved sequence present upstream or within the introns of several cellular genes. These two sites were not protected by either the 293 or MK2 nuclear proteins. Competition studies in transfected cells indicated that the reduced activity of the BKV enhancer in the HeLa cell line was due to negative regulation. Further, we have demonstrated that binding of a nuclear factor(s) to the HeLa cell-specific site is involved in the repression of enhancer activity.
Collapse
Affiliation(s)
- B W Grinnell
- Department of Molecular Biology, Lilly Research Laboratories, Indianapolis, Indiana 46285
| | | | | |
Collapse
|
50
|
Genes activated in the presence of an immunoglobulin enhancer or promoter are negatively regulated by a T-lymphoma cell line. Mol Cell Biol 1988. [PMID: 3133550 DOI: 10.1128/mcb.8.5.1932] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The tissue-specific expression of immunoglobulin genes can be partially explained by a requirement for activating factors found only in B lymphocytes and their derivatives. However, loss of immunoglobulin expression upon fusion of an immunoglobulin-producing myeloma cell with a T lymphoma cell (BW5147) or fibroblast (L cell) suggests that negatively acting factors also play a role in the tissue specificity of immunoglobulin genes. Expression of a cloned immunoglobulin heavy-chain gene introduced into myeloma cells was suppressed after fusion of the myeloma transformants with BW5147. The presence of either the immunoglobulin heavy-chain enhancer or promoter conferred suppression, under similar conditions, upon a heterologous gene that is normally expressed in both B and T lymphocytes. These immunoglobulin heavy-chain gene control regions, or gene modifications induced by them, are subject to negative control by T-lymphocyte-derived factors.
Collapse
|