101
|
Cai L, Zhu JD. The tumor-selective over-expression of the human Hsp70 gene is attributed to the aberrant controls at both initiation and elongation levels of transcription. Cell Res 2003; 13:93-109. [PMID: 12737518 DOI: 10.1038/sj.cr.7290154] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The tumor selective over-expression of the human Hsp70 gene has been well documented in human tumors, linked to the poor prognosis, being refractory to chemo- and radio-therapies as well as the advanced stage of tumorous lesions in particular. However, both the nature and details of aberrations in the control of the Hsp70 expression in tumor remain enigmatic. By comparing various upstream segments of the Hsp70 gene for each's ability to drive the luciferase reporter genes in the context of the tumor cell lines varying in their p53 status and an immortal normal liver cell line, we demonstrated in a great detail the defects in the control mechanisms at the both initiation and elongation levels of transcription being instrumental to the tumor selective profile of its expression. Our data should not only offer new insights into our understanding of the tumor specific over-expression of the human Hsp70 gene, but also paved the way for the rational utilization of the tumor selective mechanism with the Hsp70 at the central stage for targeting the therapeutic gene expression to human tumors.
Collapse
Affiliation(s)
- Ling Cai
- The State-key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, LN 25/2200, Xie-tu Road, Shanghai 200032, China
| | | |
Collapse
|
102
|
Xie Y, Zhong R, Chen C, Calderwood SK. Heat shock factor 1 contains two functional domains that mediate transcriptional repression of the c-fos and c-fms genes. J Biol Chem 2003; 278:4687-98. [PMID: 12468538 DOI: 10.1074/jbc.m210189200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heat shock factor 1 (HSF1), in addition to its pivotal role as a regulator of the heat shock response, functions as a versatile gene repressor. We have investigated the structural domains involved in gene repression using mutational analysis of the hsf1 gene. Our studies indicate that HSF1 contains two adjacent sequences located within the N-terminal half of the protein that mediate the repression of c-fos and c-fms. One region (NF) appears to be involved in quenching transcriptional activation factors on target promoters and binds to the basic zipper transcription factor NF-IL6 required for activation of c-fms and IL-1beta. The NF domain encompasses the leucine zipper 1 and 2 sequences as well as the linker domain between the DNA binding and leucine zipper regions. The function of this domain in gene repression is highly specific for HSF1, and the homologous region from conserved family member HSF2 does not restore repressive function in HSF2/HSF1 chimeras. In addition, HSF2 is not capable of binding to NF-IL6. The NF domain, although necessary for repression, is not sufficient, and a second region (REP) occupying a portion of the regulatory domain is required for repression. Neither domain functions independently, and both are required for repression. Furthermore, we constructed dominant inhibitors of c-fos repression by HSF1, which also blocked the repression of c-fms and IL-1beta, suggesting a shared mechanism for repression of these genes by HSF1. Our studies suggest a complex mechanism for gene repression by HSF1 involving the binding to and quenching of activating factors on target promoters. Mapping the structural domains involved in this process should permit further characterization of molecular mechanisms that mediate repression.
Collapse
Affiliation(s)
- Yue Xie
- Dana Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | | | | |
Collapse
|
103
|
Brodigan TM, Liu JI, Park M, Kipreos ET, Krause M. Cyclin E expression during development in Caenorhabditis elegans. Dev Biol 2003; 254:102-15. [PMID: 12606285 DOI: 10.1016/s0012-1606(02)00032-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Our interest in the coordination of cell cycle control and differentiation has led us to investigate the Caenorhabditis elegans cye-1 gene encoding the G(1) cell cycle regulator cyclin E. We have studied the expression and function of cye-1 by using monoclonal antibodies directed against CYE-1 protein, cye-1::GFP reporter genes, and a cye-1 chromosomal deletion mutation. We show that a ubiquitous embryonic pattern of expression becomes restricted and dynamic during postembryonic development. Promoter analysis reveals a relatively small region of cis-acting sequences that are necessary for the complex pattern of expression of this gene. Our studies demonstrate that two other G(1) cell cycle genes, encoding cyclin D and CDK4/6, have similarly compact promoter requirements. This suggests that a relatively simple mechanism of regulation may underlie the dynamic developmental patterns of expression exhibited by these three G(1) cell cycle genes. Our analysis of a new cye-1 deletion allele confirms and extends previous studies of two point mutations in the gene.
Collapse
Affiliation(s)
- Thomas M Brodigan
- Laboratory of Molecular Biology, NIDDK, NIH, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
104
|
Sandini S, Melchionna R, Bromuro C, La Valle R. Gene expression of 70 kDa heat shock protein of Candida albicans: transcriptional activation and response to heat shock. Med Mycol 2002; 40:471-8. [PMID: 12462526 DOI: 10.1080/mmy.40.5.471.478] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
CaHSP70 (70 kDa heat shock protein) is a highly immunogenic protein of Candida albicans. We have studied heat shock-induced expression of the CaHSP70 gene under germ tube-inductive and non-inductive conditions. The CaHSP70 upstream regulatory region was cloned and sequenced. It contains at least three heat shock elements (HSEs), specific DNA sequences that are bound by the heat shock transcription factor (HSF), and one stress response element (STRE), which is an upstream activator sequence (UAS) that causes transcription activation under stress. The binding of HSF to HSE in the CaHSP70 promoter region is constitutive, although the mobility of protein/DNA complexes is altered after heat shock. The CaHSP70 promoter was cloned into a lacZ reporter plasmid, and was able to respond to heat shock in C. albicans as well as in Saccharomyces cerevisiae.
Collapse
Affiliation(s)
- S Sandini
- Laboratory of Bacteriology and Medical Mycology, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
| | | | | | | |
Collapse
|
105
|
Shyu WC, Harn HJ, Saeki K, Kubosaki A, Matsumoto Y, Onodera T, Chen CJ, Hsu YD, Chiang YH. Molecular modulation of expression of prion protein by heat shock. Mol Neurobiol 2002; 26:1-12. [PMID: 12392052 DOI: 10.1385/mn:26:1:001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Prion diseases (also known as transmissible spongiform encephalopathies) are associated with the conversion of the normal cellular form of the prion protein (PrPC) to an abnormal scrapie-isoform (PrP(Sc). The conversion of PrP(C) to PrP(Sc) is post-translational and is owing to protein conformational change. This has led to the hypothesis that molecular chaperones may be involved in the folding of prion proteins, and hence the disease process. By treating human NT-2 cells with heat-shock stress, we found that both the mRNA levels for prion protein (PrP) and heat shock protein 70 (HSP70) increased simultaneously after heat treatment. Western-blot analysis of PrP also showed a two-fold increase in PrP protein level 3 after heat treatment. Furthermore, two heat-shock elements (HSEs) were located at the positions of -680 bp (HSE1; GGAACTATTCTTGACATTGCT), and -1653 bp (HSE2; TGAGAACTCAGGAAG) of the rat PrP (RaPrP) gene promoter. Luciferase reporter constructs of the RaPrP promoter with HSE expressed higher luciferase activity (10- to 15-fold) than those constructs without HSE. Electrophoretic gel mobility shift assay (EMSA) and super-shift assay confirmed the interaction of HSE1 and HSE2 with the heat-shock transcription factor-1 (HSTF-1). These results suggest that cellular stress up-regulates both the transcription and translation of PrP through interaction with the HSEs on the PrP gene promoter, resulting in an increase in protein synthesis.
Collapse
Affiliation(s)
- Woei-Cherng Shyu
- Department of Neurology, Mackay Memorial Hospital, Taipei, Taiwan, ROC.
| | | | | | | | | | | | | | | | | |
Collapse
|
106
|
Rojas A, Almoguera C, Carranco R, Scharf KD, Jordano J. Selective activation of the developmentally regulated Ha hsp17.6 G1 promoter by heat stress transcription factors. PLANT PHYSIOLOGY 2002; 129:1207-15. [PMID: 12114574 PMCID: PMC166514 DOI: 10.1104/pp.010927] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2001] [Revised: 01/22/2002] [Accepted: 02/27/2002] [Indexed: 05/20/2023]
Abstract
Using two well-characterized heat stress transcription factors (Hsfs) from tomato (Lycopersicon peruvianum; LpHsfA1 and LpHsfA2), we analyzed the transcriptional activation of the Ha hsp17.6 G1 promoter in sunflower (Helianthus annuus) embryos. In this system, we observed transient promoter activation only with LpHsfA2. In contrast, both factors were able to activate mutant versions of the promoter with improved consensus Hsf-binding sites. Exclusive activation by LpHsfA2 was also observed in yeast (Saccharomyces cerevisiae) without other Hsfs and with a minimal Cyc1 promoter fused to the Ha hsp17.6 G1 heat stress cis-element. Furthermore, the same promoter mutations reproduced the loss of activation selectivity, as observed in sunflower embryos. The results of in vitro binding experiments rule out differential DNA binding of the two factors as the explanation for the observed differential activation capacity. We conclude that the specific sequence of this heat stress cis-element is crucial for Hsf promoter selectivity, and that this selectivity could involve preferential transcriptional activation following DNA binding. In sunflower embryos, we also observed synergistic transcriptional activation by co-expression of LpHsfA1 and LpHsfA2. Mutational analyses of the Ha hsp17.6 G1 promoter, combined with in vitro binding assays, suggest that mixed oligomers of the two factors may be involved in promoter activation. We discuss the relevance of our observations for mechanisms of developmental regulation of plant heat stress protein genes.
Collapse
Affiliation(s)
- Anabel Rojas
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas Apartado 1052, 41080 Sevilla, Spain
| | | | | | | | | |
Collapse
|
107
|
Tachibana T, Astumi S, Shioda R, Ueno M, Uritani M, Ushimaru T. A novel non-conventional heat shock element regulates expression of MDJ1 encoding a DnaJ homolog in Saccharomyces cerevisiae. J Biol Chem 2002; 277:22140-6. [PMID: 11940587 DOI: 10.1074/jbc.m201267200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The heat shock factor (HSF) is a pivotal transcriptional factor that regulates the expression of genes encoding heat shock proteins (HSPs) via heat shock elements (HSEs). nGAAnnTTCnnGAAn functions as the minimum consensus HSE (cHSE) in vivo. Here we show that the expression of Saccharomyces cerevisiae MDJ1 encoding a mitochondrial DnaJ homolog is regulated by HSF via a novel non-consensus HSE (ncHSE(MDJ1)), which consists of three separated pentameric nGAAn motifs, nTTCn-(11 bp)-nGAAn-(5 bp)-nGAAn. This is the first evidence to show that the immediate contact of nGAAn motifs is dispensable for regulation by HSF in vivo. ncHSE(MDJ1) confers different heat shock responses versus cHSE and, unlike cHSE, definitively requires a carboxyl-terminal activation domain of HSF in the expression. ncHSE(MDJ1)-like elements are found in promoter regions of some other DnaJ-related genes. The highly conserved HSF/HSE system suggests that similar ncHSEs may be used for the expression of HSP genes in other eukaryotes including humans.
Collapse
Affiliation(s)
- Tomohusa Tachibana
- Department of Biology and Geoscience, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan
| | | | | | | | | | | |
Collapse
|
108
|
Manuel M, Rallu M, Loones MT, Zimarino V, Mezger V, Morange M. Determination of the consensus binding sequence for the purified embryonic heat shock factor 2. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:2527-37. [PMID: 12027891 DOI: 10.1046/j.1432-1033.2002.02917.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Heat shock transcription factors (HSFs) are characterized by their ability, upon activation, to bind to heat shock response elements (HSE) present in the promoter of their target genes. HSE are composed of inverted repeats of the pentamer nGAAm. In this study, we compare the embryonic HSF2 protein, purified from F9 embryonal carcinoma cells tumor, and the in vitro synthesized HSF2. We show that the context of HSF2 synthesis influences its thermosensitivity and DNA-binding properties. Therefore, we determined the consensus binding sequence for the purified embryonic HSF2 by the technique of systematic evolution of ligands by exponential enrichment (SELEX). We show that embryonic HSF2 prefers sites containing three or four nGAAm inverted pentamers and that its optimal binding sequence contains the 8-mer palindromic core 5'-TTCTAGAA-3'. The consensus binding sequence for the embryonic HSF2 will be very helpful to identify new targets for this factor, during developmental and differentiation processes.
Collapse
Affiliation(s)
- Martine Manuel
- Laboratoire de Biologie Moléculaire du Stress, Unité de Génétique Moléculaire UMR8541, Ecole Normale Supérieure, Paris, France
| | | | | | | | | | | |
Collapse
|
109
|
Jolly C, Konecny L, Grady DL, Kutskova YA, Cotto JJ, Morimoto RI, Vourc'h C. In vivo binding of active heat shock transcription factor 1 to human chromosome 9 heterochromatin during stress. J Cell Biol 2002; 156:775-81. [PMID: 11877455 PMCID: PMC2173303 DOI: 10.1083/jcb.200109018] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Activation of the mammalian heat shock transcription factor (HSF)1 by stress is a multistep process resulting in the transcription of heat shock genes. Coincident with these events is the rapid and reversible redistribution of HSF1 to discrete nuclear structures termed HSF1 granules, whose function is still unknown. Key features are that the number of granules correlates with cell ploidy, suggesting the existence of a chromosomal target. Here we show that in humans, HSF1 granules localize to the 9q11-q12 heterochromatic region. Within this locus, HSF1 binds through direct DNA-protein interaction with a nucleosome-containing subclass of satellite III repeats. HSF1 granule formation only requires the DNA binding competence and the trimerization of the factor. This is the first example of a transcriptional activator that accumulates transiently and reversibly on a chromosome-specific heterochromatic locus.
Collapse
Affiliation(s)
- Caroline Jolly
- DyOGen, INSERM U309, Institut A. Bonniot, Domaine de la Merci, 38706 La Tronche cedex, France.
| | | | | | | | | | | | | |
Collapse
|
110
|
Singh IS, He JR, Calderwood S, Hasday JD. A high affinity HSF-1 binding site in the 5'-untranslated region of the murine tumor necrosis factor-alpha gene is a transcriptional repressor. J Biol Chem 2002; 277:4981-8. [PMID: 11734555 DOI: 10.1074/jbc.m108154200] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tumor necrosis factor-alpha (TNFalpha) is a pivotal early mediator of host defenses that is essential for survival in infections. We previously reported that exposing macrophages to febrile range temperatures (FRT) (38.5-40 degrees C) markedly attenuates TNFalpha expression by causing abrupt and premature cessation of transcription. We showed that this inhibitory effect of FRT is mediated by an alternatively activated repressor form of heat shock factor 1 (HSF-1) and that a fragment of the TNFalpha gene comprising a minimal 85-nucleotide (nt) proximal promoter and the 138-nt 5'-untranslated region (UTR) was sufficient for mediating this effect. In the present study we have used an electrophoretic mobility shift assay (EMSA) to identify a high affinity binding site for HSF-1 in the 5'-UTR of the TNFalpha gene and have used a chromosome immunoprecipitation assay to show that HSF-1 binds to this region of the endogenous TNFalpha gene. Mutational inactivation of this site blocks the inhibitory effect of overexpressed HSF-1 on activity of the minimal TNFalpha promoter (-85/+138) in Raw 264.7 murine macrophages, identifying this site as an HSF-1-dependent repressor. However, the same mutation fails to block repression of a full-length (-1080/+138) TNFalpha promoter construct by HSF-1 overexpression, and HSF-1 binds to upstream sequences in the regions -1080/-845, -533/-196, and -326/-39 nt in EMSA, suggesting that additional HSF-1-dependent repressor elements are present upstream of the minimal -85-nt promoter. Furthermore, although mutation of the HSF-1 binding site in the minimal TNFalpha promoter construct abrogates HSF-1-mediated repression, the same mutation fails to abrogate repression of this construct by high levels of HSF-1 overexpression or exposure to 39.5 degrees C. This suggests that HSF-1 might repress TNFalpha transcription through redundant mechanisms, some of which might not require high affinity binding of HSF-1.
Collapse
Affiliation(s)
- Ishwar S Singh
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
| | | | | | | |
Collapse
|
111
|
Chen T, Parker CS. Dynamic association of transcriptional activation domains and regulatory regions in Saccharomyces cerevisiae heat shock factor. Proc Natl Acad Sci U S A 2002; 99:1200-5. [PMID: 11818569 PMCID: PMC122167 DOI: 10.1073/pnas.032681299] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Saccharomyces cerevisiae, the heat shock transcription factor (HSF) is thought to be a homotypic trimer that is bound to the promoters of heat shock protein (HSP) genes at both normal and heat shock temperatures. Exposure to heat shock greatly and rapidly induces HSF transcriptional activity without further increasing DNA-binding affinity. It is believed that HSF is under negative regulation at normal growth temperatures, but the detailed mechanism by which HSF is activated is still not clear. We report the analysis of mutations in a conserved arginine (residue 274) at the C-terminal end of the DNA-binding domain (DBD). Two mutations significantly increase both basal activity of HSF at normal temperatures and induced activity on heat shock. We demonstrate by coimmunoprecipitation experiments that the mutations reduce the association between the DNA-binding domain/oligomerization domain and the transcription activation domains. Our studies suggest that the DNA-binding domain of HSF can interact with activation domains directly, and this interaction is important for the repression of HSF activity under normal growth conditions. Destabilizing this interaction by heat or by mutations results in HSF transcriptional activation. We propose that Arg-274 is critical for intramolecular repression of HSF activity in normally growing cells.
Collapse
Affiliation(s)
- Tianxin Chen
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | | |
Collapse
|
112
|
Nuc K, Nuc P, Słomski R. Yellow lupine cyclophilin transcripts are highly accumulated in the nodule meristem zone. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2001; 14:1384-1394. [PMID: 11768533 DOI: 10.1094/mpmi.2001.14.12.1384] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cyclophilin (CyP) is one of the enzymes that act as peptidylprolyl cis-trans isomerases (EC 5.2.1.8). The cDNA and an intronless gene coding for cytosolic CyP have been isolated from yellow lupine. The deduced amino acid sequence of the characterized open reading frame shows approximately 80% homology with cytosolic CyP from other organisms. Southern blots of genomic DNA indicate that there is a small family of genes for CyP-related genes in the yellow lupine genome. RNA blot analyses demonstrate that CyP genes are expressed in all plant organs. The amount of CyP transcripts is dramatically increased in root nodules. In situ hybridization experiments indicate that CyP transcripts are localized mainly in meristematic tissues, with the highest level observed in the nodule meristem zone. The promoter of the sequenced gene contains 5' AAAGAT 3' and AT-rich motifs that are characteristic for some nodulin promoters.
Collapse
Affiliation(s)
- K Nuc
- August Cieszkowski University of Agriculture, Department of Biochemistry and Biotechnology, Poznań, Poland.
| | | | | |
Collapse
|
113
|
Kopecek P, Altmannová K, Weigl E. Stress proteins: nomenclature, division and functions. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2001; 145:39-47. [PMID: 12426770 DOI: 10.5507/bp.2001.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The heat shock response, characterized by increased expression of heat shock proteins (Hsps) is induced by exposure of cells and tissues to extreme conditions that cause acute or chronic stress. Hsps function as molecular chaperones in regulating cellular homeostasis and promoting survival. If the stress is too severe, a signal that leads to programmed cell death, apoptosis, is activated, thereby providing a finely tuned balance between survival and death. In addition to extracellular stimuli, several nonstressfull conditions induce Hsps during normal cellular growth and development. The enhanced heat shock gene expression in response to various stimuli is regulated by heat shock transcription factors.
Collapse
Affiliation(s)
- P Kopecek
- Department of Biology, Medical Faculty, Palacký University, 775 15 Olomouc, Czech Republic
| | | | | |
Collapse
|
114
|
Littlefield O, Nelson HC. Crystal packing interaction that blocks crystallization of a site-specific DNA binding protein-DNA complex. Proteins 2001; 45:219-28. [PMID: 11599025 DOI: 10.1002/prot.1142] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present here three high-resolution crystal structures of complexes between the DNA-binding domain of the heat-shock transcription factor (HSF) and DNA oligomers. Although the DNA oligomers contain HSF's specific binding sequence, called a heat-shock element, the crystal structures do not contain the specific protein-DNA complex. In one crystal structure, the 10 base pair DNA oligomer is statically disordered. In the other two related structures, the 12 base pair DNA oligomers are in unique positions, but the protein-DNA contacts in these two crystals are not sequence specific. In all three structures, the DNA appears to act as a rigid, polyanion scaffold to support columns of proteins in a crystalline lattice. A robust crystal packing interface between protein monomers obscures the true DNA-binding surface, known from previous genetic and biochemical studies. By redesigning the protein to interfere with the crystal lattice contacts, we were able to obtain physiologically relevant crystals in a specific protein-DNA complex. Thus, a crystal-packing interface was able to prevent the weak, but physiological relevant interactions between a protein and DNA.
Collapse
Affiliation(s)
- O Littlefield
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | | |
Collapse
|
115
|
Taricani L, Feilotter HE, Weaver C, Young PG. Expression of hsp16 in response to nucleotide depletion is regulated via the spc1 MAPK pathway in Schizosaccharomyces pombe. Nucleic Acids Res 2001; 29:3030-40. [PMID: 11452028 PMCID: PMC55794 DOI: 10.1093/nar/29.14.3030] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2001] [Revised: 05/21/2001] [Accepted: 05/21/2001] [Indexed: 11/13/2022] Open
Abstract
A universal response to elevated temperature and other forms of physiological stress is the induction of heat shock proteins (HSPs). Hsp16 in Schizosaccharomyces pombe encodes a polypeptide of predicted molecular weight 16 kDa that belongs to the HSP20/alpha-crystallin family whose members range in size from 12 to 43 kDa. Heat shock treatment increases expression of the hsp16 gene by 64-fold in wild-type cells and 141-fold in cdc22-M45 (ribonucleotide reductase) mutant cells. Hsp16 expression is mediated by the spc1 MAPK signaling pathway through the transcription factor atf1 and in addition through the HSF pathway. Nucleotide depletion or DNA damage as occurs in cdc22-M45 mutant cells, or during hydroxyurea or camptothecin treatment, is sufficient to activate hsp16 expression through atf1. Our findings suggest a novel role for small HSPs in the stress response following nucleotide depletion and DNA damage. This extends the types of damage that are sensed by the spc1 MAPK pathway via atf1.
Collapse
Affiliation(s)
- L Taricani
- Department of Biology, Bioscience Complex, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | | | | | | |
Collapse
|
116
|
Lardans V, Ram D, Lantner F, Ziv E, Schechter I. Differences in DNA-sequence recognition between the DNA-binding domain fragment and the full-length molecule of the heat-shock transcription factor of schistosome. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1519:230-4. [PMID: 11418190 DOI: 10.1016/s0167-4781(01)00220-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Binding and inhibition studies reveal that the DNA-binding domain (DBD) fragment and the full-length molecule of the heat-shock transcription factor of schistosome (SmHSF) differ in DNA sequence recognition. SmHSF does not recognize the ideal HSE consensus sequence (nGAAnnTTCnnGAAn) but recognizes a variant HSE that contains nGTAn instead of nGAAn in the third pentamer. The DBD reacts efficiently with the ideal HSE sequence and with lower affinity with the variant HSE sequence. These findings suggest that elements inside and outside the DBD contribute to the DNA-binding specificity of HSF.
Collapse
Affiliation(s)
- V Lardans
- Department of Immunology, The Weizmann Institute of Science, 76100, Rehovot, Israel
| | | | | | | | | |
Collapse
|
117
|
Hata M, Ohtsuka K. Cloning and expression of murine Hsp40 gene: differences in initiation sites between heat-induced and constitutive transcripts. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2001; 11:213-23. [PMID: 11092732 DOI: 10.3109/10425170009033235] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have isolated cDNA and genomic clones of murine Hsp40 (mmDjB1). The murine Hsp40 gene was expressed at a high level in testis and was induced by heat shock. The transcriptional initiation sites were different between heat-induced transcripts and constitutive ones. The heat-induced transcripts initiated 22 to 28 bp downstream of the TATA box, whereas constitutive transcripts initiated from multiple sites, many of which initiated upstream of the TATA box. To our knowledge, this is the first report on the heat shock-dependent usage of transcriptional start sites of a heat shock gene.
Collapse
Affiliation(s)
- M Hata
- Cell Stress Biology Research Group, Aichi Cancer Center Research Institute, Nagoya, Japan
| | | |
Collapse
|
118
|
Cicero MP, Hubl ST, Harrison CJ, Littlefield O, Hardy JA, Nelson HC. The wing in yeast heat shock transcription factor (HSF) DNA-binding domain is required for full activity. Nucleic Acids Res 2001; 29:1715-23. [PMID: 11292844 PMCID: PMC31317 DOI: 10.1093/nar/29.8.1715] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The yeast heat shock transcription factor (HSF) belongs to the winged helix family of proteins. HSF binds DNA as a trimer, and additional trimers can bind DNA co-operatively. Unlike other winged helix-turn-helix proteins, HSF's wing does not appear to contact DNA, as based on a previously solved crystal structure. Instead, the structure implies that the wing is involved in protein-protein interactions, possibly within a trimer or between adjacent trimers. To understand the function of the wing in the HSF DNA-binding domain, a Saccharomyces cerevisiae strain was created that expresses a wingless HSF protein. This strain grows normally at 30 degrees C, but shows a decrease in reporter gene expression during constitutive and heat-shocked conditions. Removal of the wing does not affect the stability or trimeric nature of a protein fragment containing the DNA-binding and trimerization domains. Removal of the wing does result in a decrease in DNA-binding affinity. This defect was mainly observed in the ability to form the first trimer-bound complex, as the formation of larger complexes is unaffected by the deletion. Our results suggest that the wing is not involved in the highly co-operative nature of HSF binding, but may be important in stabilizing the first trimer bound to DNA.
Collapse
Affiliation(s)
- M P Cicero
- Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6089, USA
| | | | | | | | | | | |
Collapse
|
119
|
Hasday JD, Singh IS. Fever and the heat shock response: distinct, partially overlapping processes. Cell Stress Chaperones 2001. [PMID: 11189454 DOI: 10.1379/1466-1268(2000)005<0471:fathsr>2.0.co;2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The heat shock response is an ancient and highly conserved process that is essential for surviving environmental stresses, including extremes of temperature. Fever is a more recently evolved response, during which organisms temporarily subject themselves to thermal stress in the face of infections. We review studies showing that fever is beneficial in the infected host. We show that core temperatures achieved during fever can activate the heat shock response and discuss some of the biochemical consequences of such an effect. We present data suggesting 4 possible mechanisms by which fever might confer protection: (1) directly killing or inhibiting growth of pathogens; (2) inducing cytoprotective heat shock proteins (Hsps) in host cells; (3) inducing expression of pathogen Hsps, an activator of host defenses; and (4) modifying and orchestrating host defenses. Two of these mechanisms directly involve the heat shock response. We describe how heat shock factor-1, the predominant heat-induced transcriptional enhancer not only activates transcription of Hsps but also regulates expression of pivotal cytokines and early response genes. The relationship between fever and the heat shock response is an illuminating example of how a more recently evolved response might exploit preexisting biochemical pathways for a new function.
Collapse
Affiliation(s)
- J D Hasday
- Department of Medicine, University of Maryland School of Medicine and the Medicine and Research Services of the Baltimore VA Medical Center, 21201, USA.
| | | |
Collapse
|
120
|
Ibrahim EC, Morange M, Dausset J, Carosella ED, Paul P. Heat shock and arsenite induce expression of the nonclassical class I histocompatibility HLA-G gene in tumor cell lines. Cell Stress Chaperones 2001. [PMID: 11005379 DOI: 10.1379/1466-1268(2000)005<0207:hsaaie>2.0.co;2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The nonclassical histocompatibility class I gene HLA-G has a tissue-restricted expression. To explore mechanisms involved in HLA-G transcriptional regulation, we have investigated the effect of stress, including heat shock and arsenite treatment, on HLA-G expression in tumor cell lines. We show that stress induces an increase of the level of the different HLA-G alternative transcripts without affecting other MHC class I HLA-A, -B, -E, and -F transcripts. A heat shock element (HSE) that binds to heat shock factor 1 (HSF1) on stress conditions was further identified within the HLA-G promoter. Considering the ability of HLA-G to modulate the function of immunocompetent cells, we hypothesize a new feature of HLA-G as a signal regulating the immune response to stress.
Collapse
Affiliation(s)
- E C Ibrahim
- CEA, Service de Recherches en Hémato-Immunologie, DSV/DRM, Hôpital Saint-Louis, Centre Hayem, Paris, France
| | | | | | | | | |
Collapse
|
121
|
Abstract
The heat shock response is an ancient and highly conserved process that is essential for surviving environmental stresses, including extremes of temperature. Fever is a more recently evolved response, during which organisms temporarily subject themselves to thermal stress in the face of infections. We review studies showing that fever is beneficial in the infected host. We show that core temperatures achieved during fever can activate the heat shock response and discuss some of the biochemical consequences of such an effect. We present data suggesting 4 possible mechanisms by which fever might confer protection: (1) directly killing or inhibiting growth of pathogens; (2) inducing cytoprotective heat shock proteins (Hsps) in host cells; (3) inducing expression of pathogen Hsps, an activator of host defenses; and (4) modifying and orchestrating host defenses. Two of these mechanisms directly involve the heat shock response. We describe how heat shock factor-1, the predominant heat-induced transcriptional enhancer not only activates transcription of Hsps but also regulates expression of pivotal cytokines and early response genes. The relationship between fever and the heat shock response is an illuminating example of how a more recently evolved response might exploit preexisting biochemical pathways for a new function.
Collapse
Affiliation(s)
- J D Hasday
- Department of Medicine, University of Maryland School of Medicine and the Medicine and Research Services of the Baltimore VA Medical Center, 21201, USA.
| | | |
Collapse
|
122
|
Ethridge RT, Ehlers RA, Hellmich MR, Rajaraman S, Evers BM. Acute pancreatitis results in induction of heat shock proteins 70 and 27 and heat shock factor-1. Pancreas 2000; 21:248-56. [PMID: 11039468 DOI: 10.1097/00006676-200010000-00005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Heat shock proteins (HSPs) 70 and 27 are stress-responsive proteins that are important for cell survival after injury; the expression of these HSPs is regulated primarily by the transcription factor heat shock factor-1 (HSF-1). The purpose of this study was to determine the effect of acute pancreatitis on pancreatic HSPs (70, 27, 60, and 90) expression and to assess potential mechanisms for HSP induction using a murine model of cerulein-induced pancreatitis. We found an increase of both HSP70 and HSP27 levels with expression noted throughout the pancreas after induction of pancreatitis. HSP60 and HSP90 levels were constitutively expressed in the pancreas and did not significantly change with acute pancreatitis. HSF-1 DNA binding activity increased in accordance with increased HSP expression. We conclude that acute pancreatitis results in a marked increase in the expression of HSP70 and HSP27. Furthermore, the induction of HSP70 and HSP27 expression was associated with a concomitant increase in HSF-1 binding activity. The increased expression of both HSP70 and HSP27 noted with pancreatic inflammation may confer a protective effect for the remaining acini after acute pancreatitis.
Collapse
Affiliation(s)
- R T Ethridge
- Department of Surgery, The University of Texas Medical Branch, Galveston 77555-0533, USA
| | | | | | | | | |
Collapse
|
123
|
Lin YH, Miyamoto C, Meighen EA. Purification and characterization of a luxO promoter binding protein LuxT from Vibrio harveyi. Protein Expr Purif 2000; 20:87-94. [PMID: 11035955 DOI: 10.1006/prep.2000.1285] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Bioluminescence in the marine bacterium Vibrio harveyi is cell density dependent and is regulated by small molecules (autoinducers) excreted by the bacteria. The autoinducer signals are relayed to a central regulator, LuxO, which acts in its phosphorylated form as a repressor of the lux operon at the early stages of cell growth. We report in these studies the purification to homogeneity of a luxO DNA binding protein (LuxT) from V. harveyi after five major chromatography steps, including a highly effective DNA affinity chromatography step and reverse-phase HPLC. Regeneration of binding activity was accomplished after HPLC and SDS-PAGE by renaturation of LuxT from guanidine hydrochloride. It was also demonstrated that the functional LuxT was a dimer of 17 kDa that bound tightly (K(d) = 2 nM) to the luxO promoter. The sequences of three tryptic peptides obtained on digestion of the purified protein did not match any sequences in the Protein Data Bank, indicating that LuxT is a new V. harveyi lux regulatory protein.
Collapse
Affiliation(s)
- Y H Lin
- Department of Biochemistry, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec, H3G 1Y6, Canada
| | | | | |
Collapse
|
124
|
Venturi CB, Erkine AM, Gross DS. Cell cycle-dependent binding of yeast heat shock factor to nucleosomes. Mol Cell Biol 2000; 20:6435-48. [PMID: 10938121 PMCID: PMC86119 DOI: 10.1128/mcb.20.17.6435-6448.2000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the nucleus, transcription factors must contend with the presence of chromatin in order to gain access to their cognate regulatory sequences. As most nuclear DNA is assembled into nucleosomes, activators must either invade a stable, preassembled nucleosome or preempt the formation of nucleosomes on newly replicated DNA, which is transiently free of histones. We have investigated the mechanism by which heat shock factor (HSF) binds to target nucleosomal heat shock elements (HSEs), using as our model a dinucleosomal heat shock promoter (hsp82-DeltaHSE1). We find that activated HSF cannot bind a stable, sequence-positioned nucleosome in G(1)-arrested cells. It can do so readily, however, following release from G(1) arrest or after the imposition of either an early S- or late G(2)-phase arrest. Surprisingly, despite the S-phase requirement, HSF nucleosomal binding activity is restored in the absence of hsp82 replication. These results contrast with the prevailing paradigm for activator-nucleosome interactions and implicate a nonreplicative, S-phase-specific event as a prerequisite for HSF binding to nucleosomal sites in vivo.
Collapse
Affiliation(s)
- C B Venturi
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130, USA
| | | | | |
Collapse
|
125
|
Ibrahim EC, Morange M, Dausset J, Carosella ED, Paul P. Heat shock and arsenite induce expression of the nonclassical class I histocompatibility HLA-G gene in tumor cell lines. Cell Stress Chaperones 2000; 5:207-18. [PMID: 11005379 PMCID: PMC312887 DOI: 10.1379/1466-1268(2000)005<0207:hsaaie>2.0.co;2] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The nonclassical histocompatibility class I gene HLA-G has a tissue-restricted expression. To explore mechanisms involved in HLA-G transcriptional regulation, we have investigated the effect of stress, including heat shock and arsenite treatment, on HLA-G expression in tumor cell lines. We show that stress induces an increase of the level of the different HLA-G alternative transcripts without affecting other MHC class I HLA-A, -B, -E, and -F transcripts. A heat shock element (HSE) that binds to heat shock factor 1 (HSF1) on stress conditions was further identified within the HLA-G promoter. Considering the ability of HLA-G to modulate the function of immunocompetent cells, we hypothesize a new feature of HLA-G as a signal regulating the immune response to stress.
Collapse
Affiliation(s)
- El Chérif Ibrahim
- CEA, Service de Recherches en Hémato-Immunologie, DSV/DRM, Hôpital Saint-Louis, Centre Hayem, 1 avenue Claude Vellefaux, 75010 Paris, France
| | - Michel Morange
- Unité de Génétique Moléculaire, Département de Biologie, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| | - Jean Dausset
- Fondation Jean Dausset, CEPH, 27 rue Juliette-Dodu, 75010 Paris, France
| | - Edgardo D Carosella
- CEA, Service de Recherches en Hémato-Immunologie, DSV/DRM, Hôpital Saint-Louis, Centre Hayem, 1 avenue Claude Vellefaux, 75010 Paris, France
| | - Pascale Paul
- CEA, Service de Recherches en Hémato-Immunologie, DSV/DRM, Hôpital Saint-Louis, Centre Hayem, 1 avenue Claude Vellefaux, 75010 Paris, France
- Correspondence to: Pascale Paul, Tel: 33 (0)1 53 72 21 42; Fax: 33 (0)1 48 03 19 60; .
| |
Collapse
|
126
|
Chen Y, Atkinson BG. Role for the Rana catesbeiana homologue of C/EBP alpha in the reprogramming of gene expression in the liver of metamorphosing tadpoles. DEVELOPMENTAL GENETICS 2000; 20:152-62. [PMID: 9144926 DOI: 10.1002/(sici)1520-6408(1997)20:2<152::aid-dvg8>3.0.co;2-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
During the spontaneous or thyroid hormone (TH)-induced metamorphosis of Rana catesbeiana, developmental changes occur in its liver that are necessary for the transition of this organism from an ammonotelic larva to a ureotelic adult. These changes include the coordinated expression of genes encoding the urea cycle enzymes carbamyl phosphate synthetase (CPS-I) and arnithine transcarbamylase (OTC). Although the expression of these genes is dependent on TH, the mechanisms(s) by which TH initiates this tissue-specific response is thought to be indirect and to involve early TH-induced upregulation of a gene(s), which, in turn, upregulates the coordinated expression of these urea-cycle enzyme genes. Herein, we demonstrate that mRNAs encoding the Rana homologue of the mammalian transcription factor C/EBP alpha (designated RcC/EBP-1) accumulate early in response to TH and that the product of these mRNAs can bind to and transactivate the promoters of both the Rana CPS-1 and OTC genes. These results support the contention that the reprogramming of gene expression in the liver of metamorphosing tadpoles involves a TH-induced cascade of gene activity in which RcC/EBP-1 and, perhaps, other transcription factors coordinate the expression of genes, such as those encoding CPS-I and OTC, whose products are characteristic of the adult liver phenotype.
Collapse
Affiliation(s)
- Y Chen
- Department of Zoology, University of Western Ontario, London, Canada
| | | |
Collapse
|
127
|
Somasundaram T, Bhat SP. Canonical heat shock element in the alpha B-crystallin gene shows tissue-specific and developmentally controlled interactions with heat shock factor. J Biol Chem 2000; 275:17154-9. [PMID: 10747896 DOI: 10.1074/jbc.m000304200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oligomerization of the heat shock factor (HSF) and its interaction with the heat shock element (HSE) are the hallmark of active transcriptional response to tangible physical or chemical stress. It is unknown if these interactions are subject to control and modulation by developmental cues and thus have tissue or stage specificity. By using promoter sequences containing a canonical HSE from the alphaB-crystallin gene, we demonstrate a tissue-specific transition from monomeric (in fetal and early neonatal stages that lack oligomeric HSF.HSE complexes) to oligomeric HSF-HSE interactions by postnatal day 10-21 in the ocular lens. Developmental control of these interactions is further demonstrated by induction of oligomeric HSF.HSE complexes in neonatal extracts by in vitro manipulations, interestingly, only in the lens and not in the brain, heart, or liver extracts. The exclusive presence of oligomeric HSF.HSE complexes in the postnatal/adult lens corresponds to known highly increased number of alphaB-crystallin transcripts in this tissue.
Collapse
Affiliation(s)
- T Somasundaram
- Jules Stein Eye Institute and Brain Research Institute, UCLA, Los Angeles, California 90095-7000, USA
| | | |
Collapse
|
128
|
Singh IS, Viscardi RM, Kalvakolanu I, Calderwood S, Hasday JD. Inhibition of tumor necrosis factor-alpha transcription in macrophages exposed to febrile range temperature. A possible role for heat shock factor-1 as a negative transcriptional regulator. J Biol Chem 2000; 275:9841-8. [PMID: 10734139 DOI: 10.1074/jbc.275.13.9841] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously reported that expression of tumor necrosis factor-alpha (TNFalpha) was attenuated in macrophages exposed to febrile range temperatures. In this study, we analyzed the influence of temperature on TNFalpha transcription in the Raw 264.7 macrophage cell line during incubation at 37 and 39.5 degrees C. The initial activation of TNFalpha transcription in response to endotoxin (LPS) was comparable in the 37 and 39.5 degrees C cell cultures, peaking within 10 min of LPS stimulation. However, the duration of transcriptional activation was markedly reduced in the 39.5 degrees C cells (30-60 min) compared with the 37 degrees C cells (2-4 h). Deletion mapping of the TNFalpha gene revealed that the proximal 85-nucleotide promoter sequence and the 5'-untranslated region were sufficient for temperature sensitivity. This sequence contains six heat shock response element (HRE) half-sites but no complete HREs. Electrophoretic mobility shift and immunoblot assays demonstrated that nuclear transclocation of heat shock factor (HSF) and its activation to a DNA-binding form occurred in the 39.5 degrees C cells in the absence of heat shock protein-70 gene activation. The proximal TNFalpha promoter/5'-untranslated region sequence competed for HSF binding to a classic HRE. Overexpression of HSF-1 reduced activity of the TNFalpha promoter. These data suggest that partial activation of HSF-1 during exposure to febrile, sub-heat shock temperatures may block TNFalpha transcription by binding to its proximal promoter or 5'-untranslated region.
Collapse
Affiliation(s)
- I S Singh
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, the University of Maryland at Baltimore Cytokine Core Laboratory, Maryland 21201, USA
| | | | | | | | | |
Collapse
|
129
|
Abstract
Living cells are continually challenged by conditions which cause acute and chronic stress. To adapt to environmental changes and survive different types of injuries, eukaryotic cells have evolved networks of different responses which detect and control diverse forms of stress. One of these responses, known as the heat shock response, has attracted a great deal of attention as a universal fundamental mechanism necessary for cell survival under a variety of unfavorable conditions. In mammalian cells, the induction of the heat shock response requires the activation and translocation to the nucleus of one or more heat shock transcription factors which control the expression of a specific set of genes encoding cytoprotective heat shock proteins. The discovery that the heat shock response is turned on under several pathological conditions and contributes to establish a cytoprotective state in a variety of human diseases, including ischemia, inflammation, and infection, has opened new perspectives in medicine and pharmacology, as molecules activating this defense mechanism appear as possible candidates for novel cytoprotective drugs. This article focuses on the regulation and function of the heat shock response in mammalian cells and discusses the molecular mechanisms involved in its activation by stress and bioactive cyclopentenone prostanoids, as well as its interaction with nuclear factor kappaB, a stress-regulated transcription factor with a pivotal role in inflammation and immunity.
Collapse
Affiliation(s)
- M G Santoro
- Department of Biology, University of Rome Tor Vergata, Italy.
| |
Collapse
|
130
|
Hatayama T, Hayakawa M. Differential temperature dependency of chemical stressors in HSF1-mediated stress response in mammalian cells. Biochem Biophys Res Commun 1999; 265:763-9. [PMID: 10600494 DOI: 10.1006/bbrc.1999.1751] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Expression of stress proteins is generally induced by a variety of stressors. To gain a better understanding of the sensing and induction mechanisms of stress responses, we studied the effects of culture temperature on responses to various stressors, since the induction of hsp70 in mammalian cells by heat shock is somehow modulated by culture temperature. Hsp70 was not induced by treatment with sodium arsenite, azetidine-2-carboxylic acid, or zinc sulfate at the level of heat shock factor (HSF) 1 activation in cells incubated at low temperature, although these treatments induced hsp70 in cells incubated at 37 degrees C. The repression of sodium arsenite or zinc sulfate-induced HSF1 activation by low temperature was not simply due to the inhibition of protein synthesis. On the other hand, heat shock and iodoacetamide induced HSF 1 activation in cells incubated at either temperature. Thus, there seem to be two kinds of stressors that induce HSF1 activation independently of or dependent on culture temperature. Furthermore, the reduction of glutathione level seemed to be essential for HSF1 activation by chemical stressors.
Collapse
Affiliation(s)
- T Hatayama
- Department of Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto, 607-8414, Japan.
| | | |
Collapse
|
131
|
Johnson K, Kirkpatrick H, Comer A, Hoffmann FM, Laughon A. Interaction of Smad complexes with tripartite DNA-binding sites. J Biol Chem 1999; 274:20709-16. [PMID: 10400705 DOI: 10.1074/jbc.274.29.20709] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Smad family of transcription factors function as effectors of transforming growth factor-beta signaling pathways. Smads form heteromultimers capable of contacting DNA through the amino-terminal MH1 domain. The MH1 domains of Smad3 and Smad4 have been shown to bind to the sequence 5'-GTCT-3'. Here we show that Smad3 and Smad4 complexes can contact three abutting GTCT sequences and that arrays of such sites elevate reporter expression relative to arrays of binding sites containing only two GTCTs. Smad3/4 complexes bound synergistically to probes containing two of the four possible arrangements of three GTCT sequences and showed a correlated ability to synergistically activate transcription through these sites. Purified Smad3 and Smad4 were both able to contact three abutting GTCT sequences and reporter experiments indicated that either protein could mediate contact with all three GTCTs. In contrast, the Smad4 MH1 domain was essential for reporter activation in combination with Smad1. Together, these results show that Smad complexes are flexible in their ability to interact with abutting GTCT triplets. In contrast, Smads have high affinity for only one orientation of abutting GTCT pairs. Functional Smad-binding sites within several native response elements contain degenerate GTCT triplets, suggesting that trimeric Smad-DNA interaction may be relevant in vivo.
Collapse
Affiliation(s)
- K Johnson
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | | | | | | | | |
Collapse
|
132
|
Abstract
Heat shock transcription factors (HSFs) are stress-responsive proteins that activate the expression of heat shock genes and are highly conserved from bakers' yeast to humans. Under basal conditions, the human HSF1 protein is maintained as an inactive monomer through intramolecular interactions between two coiled-coil domains and interactions with heat shock proteins; upon environmental, pharmacological, or physiological stress, HSF1 is converted to a homotrimer that binds to its cognate DNA binding site with high affinity. To dissect regions of HSF1 that make important contributions to the stability of the monomer under unstressed conditions, we have used functional complementation in bakers' yeast as a facile assay system. Whereas wild-type human HSF1 is restrained as an inactive monomer in yeast that is unable to substitute for the essential yeast HSF protein, mutations in the linker region between the DNA binding domain and the first coiled-coil allow HSF1 to homotrimerize and rescue the viability defect of a hsfDelta strain. Fine mapping by functional analysis of HSF1-HSF2 chimeras and point mutagenesis revealed that a small region in the amino-terminal portion of the HSF1 linker is required for maintenance of HSF1 in the monomeric state in both yeast and in transfected human 293 cells. Although linker regions in transcription factors are known to modulate DNA binding specificity, our studies suggest that the human HSF1 linker plays no role in determining HSF1 binding preferences in vivo but is a critical determinant in regulating the HSF1 monomer-trimer equilibrium.
Collapse
Affiliation(s)
- P C Liu
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0606, USA.
| | | |
Collapse
|
133
|
Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
| |
Collapse
|
134
|
Lin JT, Lis JT. Glycogen synthase phosphatase interacts with heat shock factor to activate CUP1 gene transcription in Saccharomyces cerevisiae. Mol Cell Biol 1999; 19:3237-45. [PMID: 10207049 PMCID: PMC84118 DOI: 10.1128/mcb.19.5.3237] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/1998] [Accepted: 01/12/1999] [Indexed: 12/15/2022] Open
Abstract
Upon heat shock, transcription of many stress-inducible genes is rapidly and dramatically stimulated by heat shock factor (HSF). A central region of the yeast HSF (designated HSFrr for "repression region") was previously identified and proposed to be involved in repressing the activation domain under non-heat-shock conditions. Here, we used the phage display system to isolate proteins that interact with HSFrr. This should identify factors that modulate HSF activity or directly participate in HSF-mediated transcriptional activation. We constructed a randomly sheared yeast genomic library to express yeast proteins on the surface of lambda phage. HSFrr binding phages were selected by cycles of affinity chromatography. DNA sequencing identified an HSFrr-interacting phage that contains the GAC1 gene. The GAC1 gene encodes the regulatory subunit for a type 1 serine/threonine phosphoprotein phosphatase, Glc7. Both gac1 and glc7 mutations had little effect on HSF activation of gene transcription of two heat shock genes, SSA4 and HSP82. In contrast, heat shock induction of CUP1 gene expression was completely abolished in a glc7 mutant and reduced in a gac1 mutant. The results demonstrate that the Glc7 phosphatase and its Gac1 regulatory subunit play positive roles in HSF activation of CUP1 transcription.
Collapse
Affiliation(s)
- J T Lin
- Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853-2703, USA.
| | | |
Collapse
|
135
|
Yasuda K, Ishihara K, Nakashima K, Hatayama T. Genomic cloning and promoter analysis of the mouse 105-kDa heat shock protein (HSP105) gene. Biochem Biophys Res Commun 1999; 256:75-80. [PMID: 10066425 DOI: 10.1006/bbrc.1999.0283] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The 105-kDa heat shock protein (HSP105) is a member of the high-molecular-mass heat shock protein family. We have isolated and characterized the mouse HSP105 gene including about 1.2 kb of the 5'-flanking region. The mouse HSP105 gene spans about 22 kb, consisting of 18 exons separated by 17 introns. Southern blotting analysis revealed the existence of a single copy of HSP105. Primer extension analysis revealed that the transcription initiation site was located 165 bp upstream of the ATG translation initiation codon. The 5'-promoter region of the HSP105 gene contained a TATA box, a CAAT box, an inverted CAAT box, and two GC boxes. Two heat shock element (HSE) sequences were found as four nGAAn repeats at nt -64 and nt -128. Promoter analysis using deletion derivatives revealed that a minimal region which contained the two consensus HSE sequences was active in response to heat shock and also for constitutive expression of the gene.
Collapse
Affiliation(s)
- K Yasuda
- Department of Biochemistry, Kyoto Pharmaceutical University, Kyoto, 607-8414, Japan
| | | | | | | |
Collapse
|
136
|
Ethridge RT, Hellmich MR, DuBois RN, Evers BM. Inhibition of heat-shock protein 70 induction in intestinal cells overexpressing cyclooxygenase 2. Gastroenterology 1998; 115:1454-63. [PMID: 9834273 DOI: 10.1016/s0016-5085(98)70024-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS The cyclooxygenase (COX) enzymes catalyze the initial step of prostaglandin formation; the inducible form, COX-2, plays a role in inflammation. Heat-shock protein 70 (hsp70) is a stress-responsive gene important for cell survival; induction of hsp70 appears to be mediated, in part, by the prostaglandin pathway. We determined the effect of COX-2 overexpression on hsp70 induction in rat intestinal epithelial (RIE) cells. METHODS RIE cells transfected with COX-2 complementary DNA oriented in the sense (RIE-S) or antisense (RIE-AS) direction were subjected to a heat shock; RNA and protein were harvested and analyzed by Northern and Western blots, respectively. Gel shift assays were performed to assess DNA binding. RESULTS Both hsp70 messenger RNA and HSP70 protein levels were increased in the RIE-AS cells, whereas induction was markedly inhibited in the RIE-S cells after heat shock. Inhibition of heat-shock factor binding was noted in RIE-S cells, suggesting that heat-shock transcription factor regulation may explain the inhibition of hsp70. The COX-2 selective inhibitor, NS-398, reversed the effects of COX-2 overexpression. CONCLUSIONS The results support a functional role for the prostaglandin/COX pathway in the induction of hsp70. The findings underscore a potential regulatory mechanism involving an inverse relationship between COX-2 expression and hsp70 induction.
Collapse
Affiliation(s)
- R T Ethridge
- Department of Surgery, University of Texas Medical Branch, Galveston, Texas, USA
| | | | | | | |
Collapse
|
137
|
Storozhenko S, De Pauw P, Van Montagu M, Inzé D, Kushnir S. The heat-shock element is a functional component of the Arabidopsis APX1 gene promoter. PLANT PHYSIOLOGY 1998; 118:1005-14. [PMID: 9808745 PMCID: PMC34773 DOI: 10.1104/pp.118.3.1005] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/1998] [Accepted: 07/09/1998] [Indexed: 05/18/2023]
Abstract
Ascorbate peroxidases are important enzymes that detoxify hydrogen peroxide within the cytosol and chloroplasts of plant cells. To better understand their role in oxidative stress tolerance, the transcriptional regulation of the apx1 gene from Arabidopsis was studied. The apx1 gene was expressed in all tested organs of Arabidopsis; mRNA levels were low in roots, leaves, and stems and high in flowers. Steady-state mRNA levels in leaves or cell suspensions increased after treatment with methyl viologen, ethephon, high temperature, and illumination of etiolated seedlings. A putative heat-shock cis element found in the apx1 promoter was shown to be recognized by the tomato (Lycopersicon esculentum) heat-shock factor in vitro and to be responsible for the in vivo heat-shock induction of the gene. The heat-shock cis element also contributed partially to the induction of the gene by oxidative stress. By using in vivo dimethyl sulfate footprinting, we showed that proteins interacted with a G/C-rich element found in the apx1 promoter.
Collapse
Affiliation(s)
- S Storozhenko
- Laboratorium voor Genetica, Departement Genetica, Vlaams Interuniversitair Instituut voor Biotechnologie, Belgium
| | | | | | | | | |
Collapse
|
138
|
Escolar L, Pérez-Martín J, de Lorenzo V. Binding of the fur (ferric uptake regulator) repressor of Escherichia coli to arrays of the GATAAT sequence. J Mol Biol 1998; 283:537-47. [PMID: 9784364 DOI: 10.1006/jmbi.1998.2119] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The mode of DNA binding of the Fur (ferric uptake regulator) repressor which controls transcription of iron-responsive genes in Escherichia coli, has been re-examined. Using as a reference the known sites at the promoter of the aerobactin operon of Escherichia coli, we have compared in detail the patterns of interaction between the purified Fur protein and natural or synthetic DNA targets. DNase I and hydroxyl radical footprinting, as well as missing-T assays, consistently revealed that functional Fur sites are composed of a minimum of three repeats of the hexameric motif GATAAT rather than by a palindromic 19 bp target sequence. Extended binding sites, constructed by stepwise addition of one or two direct repeats of the same sequence, were occupied co-operatively by Fur with the same pattern of interactions as those observed with the core of three repeats. This indicated that functional sites with a range of affinities can be formed by the addition of discrete GATAAT extensions to a minimal recognition sequence. The fashion in which Fur binds its target, virtually unknown in prokaryotic transcriptional regulators, accounts for the observed helical wrapping of the protein around the DNA helix.
Collapse
Affiliation(s)
- L Escolar
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, 28049, Spain
| | | | | |
Collapse
|
139
|
Mechanism of heat induction of albumin in early embryonic rat liver. J Biosci 1998. [DOI: 10.1007/bf02936132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
140
|
Hung JJ, Cheng TJ, Dah-Tsyr Chang M, Chen KD, Huang HL, Lai YK. Involvement of heat shock elements and basal transcription elements in the differential induction of the 70-kDa heat shock protein and its cognate by cadmium chloride in 9L rat brain tumor cells. J Cell Biochem 1998. [DOI: 10.1002/(sici)1097-4644(19981001)71:1<21::aid-jcb3>3.0.co;2-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
141
|
Geraghty DS, Sucic HB, Chen J, Pederson DS. Evidence that partial unwrapping of DNA from nucleosomes facilitates the binding of heat shock factor following DNA replication in yeast. J Biol Chem 1998; 273:20463-72. [PMID: 9685401 DOI: 10.1074/jbc.273.32.20463] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, heat shock transcription factor (HSF) binds heat shock element (HSE) DNA shortly after DNA replication, independently of its activation by heat shock. To determine if HSF binding occurs before newly replicated DNA is packaged into nucleosomes, we inserted an HSE into a DNA segment that normally forms a positioned nucleosome in vivo. Transcription from constructs designed to create steric competition between binding of HSF and histone H2A-H2B dimers was generally poor, suggesting that nucleosome assembly precedes and inhibits HSF binding. However, one such construct was as transcriptionally active as a nucleosome-free control. Structural analyses suggested that approximately 40 base pairs of DNA, including the HSE, had unwrapped from the 3' edge of the histone octamer, allowing HSF to bind; approximately 100 base pairs remained in association with the histone octamer, with the same translational and rotational orientation as was seen for the poorly transcribed constructs. Modeling studies suggest that the active and inactive constructs differ from one another in the ease with which the HSE and flanking sequences can adopt the curvature needed to form a stable nucleosome. These differences may influence the probability of DNA unwrapping from already assembled nucleosomes and the subsequent binding of HSF.
Collapse
Affiliation(s)
- D S Geraghty
- Department of Microbiology and Molecular Genetics and the Markey Center for Molecular Genetics, University of Vermont, Burlington, Vermont 05405-0068, USA
| | | | | | | |
Collapse
|
142
|
Brunt SA, Borkar M, Silver JC. Regulation of hsp90 and hsp70 genes during antheridiol-induced hyphal branching in the oomycete Achlya ambisexualis. Fungal Genet Biol 1998; 24:310-24. [PMID: 9756712 DOI: 10.1006/fgbi.1998.1056] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
When mycelia of Achlya ambisexualis J. Raper strain E87 were undergoing antheridial branching, a marked increase was observed in the levels of transcript populations encoding the heat shock protein chaperone Hsp90 and transcript populations encoding three different Hsp70-family heat shock protein chaperones, respectively. Although up to 90% of hyphae in the hormone-treated thalli were undergoing antheridial branching, no similar increase in the level of transcripts encoding actin was observed. Nuclear run-on assays demonstrated that the observed antheridiol-induced increases in the levels of the chaperone RNAs resulted from increased transcription. Although not tested for function, the nucleotide sequence of the 5' flanking region of each of the two A. ambisexualis hsp90 genes revealed a diversity of sequences and motifs similar or identical to the sequences of known transcription factor response elements. Among these potential response element sequences observed in the A. ambisexualis genes were motifs observed also in animal steroid hormone response elements. Surrounding the primer-extension determined transcription start site of each A. ambisexualis hsp90 gene was a 16-nucleotide sequence that matched in 14 out of 16 nucleotides a sequence found in the transcription initiation region of many different oomycete genes.
Collapse
Affiliation(s)
- S A Brunt
- Division of Life Sciences, University of Toronto at Scarborough, Scarborough, Ontario, M1C 1A4, Canada
| | | | | |
Collapse
|
143
|
Emmerhoff OJ, Klenk HP, Birkeland NK. Characterization and sequence comparison of temperature-regulated chaperonins from the hyperthermophilic archaeon Archaeoglobus fulgidus. Gene X 1998; 215:431-8. [PMID: 9714842 DOI: 10.1016/s0378-1119(98)00314-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have cloned and sequenced the genes encoding two chaperonin subunits (Cpn-alpha and Cpn-beta), from Archaeoglobus fulgidus, a sulfate-reducing hyperthermophilic archaeon. The genes encode proteins of 545 amino acids with calculated Mr of 58 977 and 59 683. Both proteins have been identified in cytoplasmic fractions of A. fulgidus by Western analysis using antibodies raised against one of the subunits expressed in Escherichia coli, and by N-terminal amino acid sequencing of chaperonin complexes purified by immunoprecipitation. The chaperonin genes appear to be under heat shock regulation, as both proteins accumulate following temperature shift-up of growing A. fulgidus cells, implying a role of the chaperonin in thermoadaptation. Canonical Box A and Box B archaeal promoter sequences, as well as additional conserved putative signal sequences, are located upstream of the start codons. A phylogenetic analysis using all the available archaeal chaperonin sequences, suggests that the alpha and beta subunits are the results of late gene duplications that took place well after the establishment of the main archaeal evolutionary lines.
Collapse
Affiliation(s)
- O J Emmerhoff
- Department of Microbiology, University of Bergen, Jahnebakken 5, N-5020, Bergen, Norway
| | | | | |
Collapse
|
144
|
Abstract
Four polyubiquitin genes, PUB1, PUB2, PUB3 and PUB4, were isolated from a pea (Pisum sativum L. cv Alaska) genomic library and completely sequenced. They represent all of the four polyubiquitin genes of the ubiquitin gene family in pea. The coding regions of the genes contain five or six coding units arranged as tandem repeats. The different coding repeats of the four genes share homologies between 75 and 97%, encoding the same protein of 76 amino acids identical to those from other higher plants. The open reading frames of PUB1, PUB2 and PUB4 terminate in the additional amino acid, phenylalanine (F), and PUB3 terminates in isoleucine (I). The polyubiquitin genes all contain intron sequences ranging from 584 to 1114 bp immediately 5' to the ATG initiation codon of the first coding sequence. Of the four genes, three are associated with long AT-rich (85.4-89.4% A+T) sequences ranging from about 331 to 478 bp at their 5' or 3' ends. The PUB4 gene was found to be linked to a moderate to highly repetitive DNA at its 5' flanking sequence. The greater sequence homology between different genes than among individual repeating units of a gene suggests that the polyubiquitin genes may have arisen by gene duplication of a single gene sequence.
Collapse
Affiliation(s)
- X Xia
- Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada
| | | |
Collapse
|
145
|
Kotagiri S, Edenberg HJ. Regulation of human alcohol dehydrogenase gene ADH7: importance of an AP-1 site. DNA Cell Biol 1998; 17:583-90. [PMID: 9703017 DOI: 10.1089/dna.1998.17.583] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The structure and function of the human alcohol dehydrogenase 7 (ADH7) promoter were analyzed. A promoter fragment extending to bp -232 functioned well in H4IIE-C3, CV-1, and HeLa cells, whereas the region extending further upstream to bp -799 had no significant effect on activity. We identified cis-acting elements in the proximal 232 bp and examined their effect on promoter activity. Mutation of site A, where c-Jun bound, caused a drastic decrease in the promoter activity in H4IIE-C3 and CV-1 cells, suggesting that AP-1 plays an important role in the regulation of ADH7. Mutation of site B also caused a large drop in promoter activity in both cell lines; C/EBPalpha can bind to this site, but because the site affects activity approximately equally in CV-1 cells that lack C/EBPalpha and in H4IIE-C3 cells that contain low levels, other proteins are likely to play the major roles in vivo. Mutation of site C, where C/EBP bound and c-Jun bound weakly, had different effects in the two cell lines: in H4IIE-C3 cells, the site C mutation did not significantly increase promoter activity, whereas in CV-1 cells, which lack C/EBPalpha, it led to a doubling of activity. Surprisingly, cotransfection of the wild-type promoter with C/EBPa or C/EBPbeta led to a decrease in promoter activity, which might in part explain the lack of activity of ADH7 in adult liver.
Collapse
Affiliation(s)
- S Kotagiri
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202-5122, USA
| | | |
Collapse
|
146
|
Victor M, Benecke BJ. Expression levels of heat shock factors are not functionally coupled to the rate of expression of heat shock genes. Mol Biol Rep 1998; 25:135-41. [PMID: 9700049 DOI: 10.1023/a:1006801205904] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The expression patterns of two mammalian heat shock factors (HSFs) were analysed in cell systems known to reflect an altered heat shock response. For being able to discriminate between the two closely related factors HSF 1 and HSF 2, specific cDNA sequences were cloned and used to generate antisense RNAs as hybridization probes. In general, in various cell lines expression of the two heat shock factors was clearly different. These expression patterns of the HSF genes were not influenced by retinoic acid-induced differentiation of human NT2 and mouse F9 teratocarcinoma cells. Generally, HSF 2 expression was extremely low, whereas the significantly higher expression of HSF 1 revealed cell specific differences. The highest expression rates of both HSFs were observed in 293 cells. To examine whether these high levels are involved in the constitutive expression of heat shock genes in these cells, we analysed the binding pattern of 293 cell proteins to the heat shock elements (HSEs). As with other cells, HSE-binding activity in 293 cells was only observed after heat shock treatment. This points to an HSE-independent way for high level expression of heat shock genes in these cells.
Collapse
Affiliation(s)
- M Victor
- Department of Biochemistry, Ruhr-University Bochum, Germany
| | | |
Collapse
|
147
|
Streaker ED, Beckett D. A map of the biotin repressor-biotin operator interface: binding of a winged helix-turn-helix protein dimer to a forty base-pair site. J Mol Biol 1998; 278:787-800. [PMID: 9614942 DOI: 10.1006/jmbi.1998.1733] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Escherichia coli biotin repressor is a member of the "winged helix-turn-helix" class of site-specific DNA binding proteins. The protein binds as a dimer to the 40 bp biotin operator sequence. Although the structure of the aporepressor has been solved by X-ray crystallographic techniques, no structure of the holorepressor-DNA complex is yet available. In order to characterize the structural features of the biotin repressor-biotin operator interface we have applied a number of solution techniques including DNase I, hydroxyl radical and dimethyl sulfate footprinting and the circular permutation or "bending" assay. Results of these combined studies indicate that each repressor monomer forms a bipartite interface with each half-site of the biotin operator sequence. The results imply that, in addition to the helix-turn-helix module of each monomer, a second structural element participates in the protein-DNA interface. The two bipartite protein-DNA interfaces appear, moreover, to primarily involve the two 12 bp termini of the operator site. Results of combined DNase I footprinting and circular permutation analysis indicate, furthermore, that the central 16 bp region that links the two termini becomes distorted concomitant with binding of holoBirA.
Collapse
Affiliation(s)
- E D Streaker
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County 21250, USA
| | | |
Collapse
|
148
|
Nagata K. Expression and function of heat shock protein 47: a collagen-specific molecular chaperone in the endoplasmic reticulum. Matrix Biol 1998; 16:379-86. [PMID: 9524358 DOI: 10.1016/s0945-053x(98)90011-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Heat shock protein (HSP) 47 is a collagen-binding stress protein localized in the endoplasmic reticulum (ER). In addition to stress-inducibility through heat shock element-heat shock factor interaction, the expression of HSP47 under normal conditions always correlates with that of collagens in various cell types and tissues. Both HSP47 and types I and III collagens are also dramatically induced under pathophysiological conditions such as liver fibrosis. HSP47 transiently associates with procollagen in the ER and dissociates from it in the cis-Golgi compartment. Possible functions of HSP47 as a molecular chaperone specific for procollagen are discussed: prevention of nascent procollagen chains from forming aggregates, effect on the modification of procollagen, inhibition of intracellular degradation of procollagen, quality control mechanisms under stress conditions, and effect on the secretion from the ER to the Golgi compartment.
Collapse
Affiliation(s)
- K Nagata
- Department of Cell Biology, Kyoto University, Japan
| |
Collapse
|
149
|
Thompson DK, Daniels CJ. Heat shock inducibility of an archaeal TATA-like promoter is controlled by adjacent sequence elements. Mol Microbiol 1998; 27:541-51. [PMID: 9489666 DOI: 10.1046/j.1365-2958.1998.00698.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The expression of a heat-inducible cct1 (chaperonin-containing Tcp-1) family member gene is regulated at the transcription level in the archaeon Haloferax volcanii. Transcriptional fusions of the cct1 promoter region with a yeast proline tRNA reporter gene were constructed to analyse the functional domains of this archaeal heat shock promoter. Both basal and heat-induced transcription of the reporter gene was directed by an archaeal consensus TATA element (5'-TTTATA-3') centred 25bp upstream of the transcription start site. Deletion mutagenesis indicated that the 5' boundary of the cct1 regulatory region mapped to position -37. Nucleotide alignment with the 5' flanking regions of two additional cct-related genes identified in H. volcanii showed a high degree of sequence conservation between positions +1 and -37, especially in and immediately surrounding the TATA element of the putative core promoter. Mutational analysis of conserved sequences demonstrated that basal and heat-induced transcription required sequence elements located upstream and downstream of the TATA-box. These findings indicate that the regulatory sequences involved in heat-induced transcription lie within the core promoter region and suggest that the mechanism controlling heat shock gene expression in H. volcanii differs from the bacterial and eukaryal strategies.
Collapse
Affiliation(s)
- D K Thompson
- Department of Microbiology, The Ohio State University, Columbus 43210, USA
| | | |
Collapse
|
150
|
Liu XD, Liu PC, Santoro N, Thiele DJ. Conservation of a stress response: human heat shock transcription factors functionally substitute for yeast HSF. EMBO J 1997; 16:6466-77. [PMID: 9351828 PMCID: PMC1170252 DOI: 10.1093/emboj/16.21.6466] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Heat shock factors (HSF) are important eukaryotic stress responsive transcription factors which are highly structurally conserved from yeast to mammals. HSFs bind as homotrimers to conserved promoter DNA recognition sites called HSEs. The baker's yeast Saccharomyces cerevisiae possesses a single essential HSF gene, while distinct HSF isoforms have been identified in humans. To ascertain the degree of functional similarity between the yeast and human HSF proteins, human HSF1 and HSF2 were expressed in yeast cells lacking the endogenous HSF gene. We demonstrate that human HSF2, but not HSF1, homotrimerizes and functionally complements the viability defect associated with a deletion of the yeast HSF gene. However, derivatives of hHSF1 that give rise to a trimerized protein, through disruption of a carboxyl- or aminoterminal coiled-coil domain thought to engage in intramolecular interactions that maintain the protein in a monomeric state, functionally substitute for yeast HSF. Surprisingly, hHSF2 expressed in yeast activates target gene transcription in response to thermal stress. Moreover, hHSF1 and hHSF2 exhibit selectivity for transcriptional activation of two distinct yeast heat shock responsive genes, which correlate with previously established mammalian HSF DNA binding preferences in vitro. These results provide new insight into the function of human HSF isoforms, and demonstrate the remarkable functional conservation between yeast and human HSFs, critical transcription factors required for responses to physiological, pharmacological and environmental stresses.
Collapse
Affiliation(s)
- X D Liu
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor 48109-0606, USA
| | | | | | | |
Collapse
|