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Jing Z, Gangalum RK, Mock DC, Bhat SP. A gene-specific non-enhancer sequence is critical for expression from the promoter of the small heat shock protein gene αB-crystallin. Hum Genomics 2014; 8:5. [PMID: 24589182 PMCID: PMC3975602 DOI: 10.1186/1479-7364-8-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 02/10/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Deciphering of the information content of eukaryotic promoters has remained confined to universal landmarks and conserved sequence elements such as enhancers and transcription factor binding motifs, which are considered sufficient for gene activation and regulation. Gene-specific sequences, interspersed between the canonical transacting factor binding sites or adjoining them within a promoter, are generally taken to be devoid of any regulatory information and have therefore been largely ignored. An unanswered question therefore is, do gene-specific sequences within a eukaryotic promoter have a role in gene activation? Here, we present an exhaustive experimental analysis of a gene-specific sequence adjoining the heat shock element (HSE) in the proximal promoter of the small heat shock protein gene, αB-crystallin (cryab). These sequences are highly conserved between the rodents and the humans. RESULTS Using human retinal pigment epithelial cells in culture as the host, we have identified a 10-bp gene-specific promoter sequence (GPS), which, unlike an enhancer, controls expression from the promoter of this gene, only when in appropriate position and orientation. Notably, the data suggests that GPS in comparison with the HSE works in a context-independent fashion. Additionally, when moved upstream, about a nucleosome length of DNA (-154 bp) from the transcription start site (TSS), the activity of the promoter is markedly inhibited, suggesting its involvement in local promoter access. Importantly, we demonstrate that deletion of the GPS results in complete loss of cryab promoter activity in transgenic mice. CONCLUSIONS These data suggest that gene-specific sequences such as the GPS, identified here, may have critical roles in regulating gene-specific activity from eukaryotic promoters.
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Affiliation(s)
| | | | | | - Suraj P Bhat
- Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA.
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Jing Z, Gangalum RK, Lee JZ, Mock D, Bhat SP. Cell-type-dependent access of HSF1 and HSF4 to αB-crystallin promoter during heat shock. Cell Stress Chaperones 2013; 18:377-87. [PMID: 23264262 PMCID: PMC3631099 DOI: 10.1007/s12192-012-0386-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 10/18/2012] [Accepted: 11/13/2012] [Indexed: 10/27/2022] Open
Abstract
Epithelial cells and fibroblasts both express heat shock transcription factors, HSF1 and HSF4, yet they respond to heat shock differentially. For example, while HSP70 is induced in both cell types, the small heat shock protein, αB-crystallin gene (CRYAB) that contains a canonical heat shock promoter, is only induced in fibroblasts. A canonical heat shock promoter contains three or more inverted repeats of the pentanucleotide 5'-nGAAn-3' that make the heat shock element. It is known that, in vitro, promoter architecture (the order and spacing of these repeats) impacts the interaction of various heat shock transcription factors (HSFs) with the heat shock promoter, but in vivo relevance of these binding preferences so far as the expression is concerned is poorly understood. In this report, we first establish cell-type-dependent differential expression of CRYAB in four established cell lines and then working with adult human retinal pigment epithelial cells and NIH3T3 fibroblasts and employing chromatin immunoprecipitation, attempt to relate expression to promoter occupancy by HSF1 and HSF4. We show that HSF4 occupies only CRYAB and not HSP70 promoter in epithelial cells, while HSF1 occupies only HSP70 promoter in both cell types, and cryab promoter, only in heat shocked fibroblasts; HSF4, on the other hand, is never seen on these two promoters in NIH3T3 fibroblasts. This comparative analysis with CRYAB and HSP70 demonstrates that differential heat shock response is controlled by cell-type-dependent access of HSFs (HSF1 and HSF4) to specific promoters, independent of the promoter architecture.
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Affiliation(s)
- Zhe Jing
- />Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Brain Research Institute and Molecular Biology Institute, University of California, Los Angeles, CA 90095 USA
| | - Rajendra K. Gangalum
- />Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Brain Research Institute and Molecular Biology Institute, University of California, Los Angeles, CA 90095 USA
| | - Josh Z. Lee
- />Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Brain Research Institute and Molecular Biology Institute, University of California, Los Angeles, CA 90095 USA
| | - Dennis Mock
- />Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Brain Research Institute and Molecular Biology Institute, University of California, Los Angeles, CA 90095 USA
| | - Suraj P. Bhat
- />Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Brain Research Institute and Molecular Biology Institute, University of California, Los Angeles, CA 90095 USA
- />Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095 USA
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White BG, Williams SJ, Highmore K, Macphee DJ. Small heat shock protein 27 (Hsp27) expression is highly induced in rat myometrium during late pregnancy and labour. Reproduction 2005; 129:115-26. [PMID: 15615903 DOI: 10.1530/rep.1.00426] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The underlying mechanisms that regulate uterine contractions during labour are still poorly understood. A candidate regulatory protein is heat shock protein 27 (Hsp27). It belongs to the small heat shock protein family and can regulate actin cytoskeleton dynamics, act as a chaperone, and may regulate contractile protein activation. As a result, we hypothesized that Hsp27 expression would be highly induced during late pregnancy and labour. Hsp27 mRNA expression was significantly elevated (P <0.05) on days 17 to 22 of gestation. In addition, immunoblot analysis demonstrated that detection of total Hsp27 increased (P <0.05) between day 21 and 1 day post-partum (PP) inclusive. Since phosphorylation of Hsp27 has been reported to be a prerequisite for smooth muscle contraction, we examined the temporal and spatial expression of Ser-15 phosphorylated Hsp27. Immunoblot analysis showed that the detection of Ser-15 phosphorylated Hsp27 significantly increased (P <0.05) between days 19 and 23 (active labour) inclusive, in parallel with detection of total Hsp27. Immunocytochemical analysis of Ser-15 phosphorylated Hsp27 expression in situ demonstrated that phosphorylated Hsp27 in circular muscle became detectable in peri-nuclear and membrane regions on days 19 to 22, but was primarily restricted to the cytoplasm on days 23 to PP. In contrast, phosphorylated Hsp27 in longitudinal muscle was primarily detected in myocyte membranes on days 15 to 22, and then also became detectable in the cytoplasm of myocytes on days 23 and PP. Our results demonstrate that Hsp27 expression is highly upregulated during late pregnancy and labour and suggest that Hsp27 is a potential candidate contraction-associated protein.
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Affiliation(s)
- B G White
- Division of Basic Medical Sciences, Health Sciences Centre, Faculty of Medicine, Memorial University of Newfoundland, St John's, Newfoundland and Labrador, Canada A1B 3V6
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Chowdary T, Raman B, Ramakrishna T, Rao C. Mammalian Hsp22 is a heat-inducible small heat-shock protein with chaperone-like activity. Biochem J 2004; 381:379-87. [PMID: 15030316 PMCID: PMC1133843 DOI: 10.1042/bj20031958] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 03/05/2004] [Accepted: 03/19/2004] [Indexed: 11/17/2022]
Abstract
A newly identified 22 kDa protein that interacts with Hsp27 (heat-shock protein 27) was shown to possess the characteristic alpha-crystallin domain, hence named Hsp22, and categorized as a member of the sHsp (small Hsp) family. Independent studies from different laboratories reported the protein with different names such as Hsp22, H11 kinase, E2IG1 and HspB8. We have identified, on the basis of the nucleotide sequence analysis, putative heat-shock factor 1 binding sites upstream of the Hsp22 translation start site. We demonstrate that indeed Hsp22 is heat-inducible. We show, in vitro, chaperone-like activity of Hsp22 in preventing dithiothreitol-induced aggregation of insulin and thermal aggregation of citrate synthase. We have cloned rat Hsp22, overexpressed and purified the protein to homogeneity and studied its structural and functional aspects. We find that Hsp22 fragments on storage. MS analysis of fragments suggests that the fragmentation might be due to the presence of labile peptide bonds. We have established conditions to improve its stability. Far-UV CD indicates a randomly coiled structure for Hsp22. Quaternary structure analyses by glycerol density-gradient centrifugation and gel filtration chromatography show that Hsp22 exists as a monomer in vitro, unlike other members of the sHsp family. Hsp22 exhibits significantly exposed hydrophobic surfaces as reported by bis-8-anilinonaphthalene-l-sulphonic acid fluorescence. We find that the chaperone-like activity is temperature dependent. Thus Hsp22 appears to be a true member of the sHsp family, which exists as a monomer in vitro and exhibits chaperone-like activity.
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Affiliation(s)
| | | | | | - Chintalagiri Mohan Rao
- Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
- To whom correspondence should be addressed (e-mail )
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Doerwald L, van Rheede T, Dirks RP, Madsen O, Rexwinkel R, van Genesen ST, Martens GJ, de Jong WW, Lubsen NH. Sequence and Functional Conservation of the Intergenic Region Between the Head-to-Head Genes Encoding the Small Heat Shock Proteins αB-Crystallin and HspB2 in the Mammalian Lineage. J Mol Evol 2004; 59:674-86. [PMID: 15693623 DOI: 10.1007/s00239-004-2659-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An unexpected feature of the large mammalian genome is the frequent occurrence of closely linked head-to-head gene pairs. Close apposition of such gene pairs has been suggested to be due to sharing of regulatory elements. We show here that the head-to-head gene pair encoding two small heat shock proteins, alphaB-crystallin and HspB2, is closely linked in all major mammalian clades, suggesting that this close linkage is of selective advantage. Yet alphaB-crystallin is abundantly expressed in lens and muscle and in response to a heat shock, while HspB2 is abundant only in muscle and not upregulated by a heat shock. The intergenic distance between the genes for these two proteins in mammals ranges from 645 bp (platypus) to 1069 bp (opossum), with an average of about 900 bp; in chicken the distance was the same as in duck (1.6 kb). Phylogenetic footprinting and sequence alignment identified a number of conserved sequence elements close to the HspB2 promoter and two farther upstream. All known regulatory elements of the mouse alphaB-crystallin promoter are conserved, except in platypus and birds. The lens-specific region 1 (LSR1) and the heat shock elements (HSEs) lack in birds; in platypus the LSR1 is reduced to a Pax-6 site, while the Pax-6 site in LSR2 and a HSE are absent. Most likely the primordial mammalian alphaB-crystallin promoter had two LSRs and two HSEs. In transfection experiments the platypus alphaB-crystallin promoter retained heat shock responsiveness and lens expression. It also directed lens expression in Xenopus laevis transgenes, as did the HspB2 promoter of rat or blind mole rat. Deletion of the middle of the intergenic region including the upstream enhancer affected the activity of both the rat alphaB-crystallin and the HspB2 promoters, suggesting sharing of the enhancer region by the two promoters.
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Affiliation(s)
- Linda Doerwald
- Department of Biochemistry, Faculty of Science, University of Nijmegen, Nijmegen, The Netherlands
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Somasundaram T, Bhat SP. Developmentally dictated expression of heat shock factors: exclusive expression of HSF4 in the postnatal lens and its specific interaction with alphaB-crystallin heat shock promoter. J Biol Chem 2004; 279:44497-503. [PMID: 15308659 DOI: 10.1074/jbc.m405813200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular cascade of stress response in higher eukaryotes commences in the cytoplasm with the trimerization of the heat shock factor 1 (HSF1), followed by its transport to the nucleus, where it binds to the heat shock element leading to the activation of transcription from the down-stream gene(s). This well-established paradigm has been mostly studied in cultured cells. The developmental and tissue-specific control of the heat shock transcription factors (HSFs) and their interactions with heat shock promoters remain unexplored. We report here that in the rat lens, among the three mammalian HSFs, expression of HSF1 and HSF2 is largely fetal, whereas the expression of HSF4 is predominantly postnatal. Similar pattern of expression of HSF1 and HSF4 is seen in fetal and adult human lenses. This stage-specific inverse relationship between the expression of HSF1/2 and HSF4 suggests tissue-specific management of stress depending on the presence or absence of specific HSF(s). In addition to real-time PCR and immunoblotting, gel mobility shift assays, coupled with specific antibodies and HSE probes, derived from three different heat shock promoters, establish that there is no HSF1 or HSF2 binding activity in the postnatal lens nuclear extracts. Using this unique, developmentally modulated in vivo system, we demonstrate 1) specific patterns of HSF4 binding to heat shock elements derived from alphaB-crystallin, Hsp70, and Hsp82 promoters and 2) that it is HSF4 and not HSF1 or HSF2 that interacts with the canonical heat shock element of the alphaB-crystallin gene.
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Affiliation(s)
- T Somasundaram
- Jules Stein Eye Institute, University of California, Los Angeles, California 90095-7000, USA
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Bhat SP. Crystallins, genes and cataract. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; 60:205-62. [PMID: 12790344 DOI: 10.1007/978-3-0348-8012-1_7] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Far from being a physical entity, assembled of inanimate structural proteins, the ocular lens epitomizes the biological ingenuity that sustains an essential and near-perfect physical system of immaculate optics. Crystallins (alpha, beta, and gamma) provide transparency by dint of their high concentration, but it is debatable whether proteins that provide transparency are any different, biologically or structurally, from those that are present in non-transparent structures or tissues. It is becoming increasingly clear that crystallins may have a plethora of metabolic and regulatory functions, both within the lens as well as outside of it. Alpha-crystallins are members of a small heat shock family of proteins and beta/gamma-crystallins belong to the family of epidermis-specific differentiation proteins. Crystallin gene expression has been studied from the perspective of the lens specificity of their promoters. Mutations in alpha-, beta-, and gamma-crystallins are linked with the phenotype of the loss of transparency. Understanding catalytic, non-structural properties of crystallins may be critical for understanding the malfunction in molecular cascades that lead to cataractogenesis and its eventual therapeutic amelioration.
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Affiliation(s)
- Suraj P Bhat
- Jules Stein Eye Institute and Brain Research Institute, Geffen School of Medicine at UCLA, Los Angeles, CA 90077-7000, USA.
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8
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Hawse JR, Cumming JR, Oppermann B, Sheets NL, Reddy VN, Kantorow M. Activation of metallothioneins and alpha-crystallin/sHSPs in human lens epithelial cells by specific metals and the metal content of aging clear human lenses. Invest Ophthalmol Vis Sci 2003; 44:672-9. [PMID: 12556398 PMCID: PMC2825746 DOI: 10.1167/iovs.02-0018] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify those metallothionein and alpha-crystallin/small heat-shock genes induced by toxic metals in human lens cells and to evaluate the levels of these metals between young and aged human lenses. METHODS Human SRA01/04 and primary human lens epithelial cells were cultured and exposed to Cd(2+), Cu(2+), and Zn(2+). The levels of lens metallothioneins (Ig, If, Ih, Ie, and IIa) and alpha-crystallin/small heat-shock (alphaA-crystallin, alphaB-crystallin, and HSP27) genes were analyzed by semiquantitative and quantitative competitive RT-PCR. The content of aluminum, cadmium, calcium, chromium, copper, iron, lead, magnesium, manganese, nickel, potassium, sodium, and zinc in young (mean, 32.8 years), middle-aged (mean, 52.3 years), and old (mean, 70.5 years) human lenses was analyzed by inductively coupled plasma-emission spectroscopy. RESULTS Lens metallothioneins (Ig, If, Ih, Ie, and IIa) and alpha-crystallin/small heat-shock genes (alphaA-crystallin, alphaB-crystallin, and HSP27) were differentially induced by specific metals in SRA01/04 human lens epithelial cells. Cd(2+) and Zn(2+), but not Cu(2+), induced the metallothioneins, whereas Cd(2+) and Cu(2+), but not Zn(2+), induced alphaB-crystallin and HSP27. alphaA-crystallin was induced by Cu(2+) only. Similar responses of the metallothionein IIa gene were detected in identically treated primary human lens epithelial cells. Cd(2+) and Zn(2+) induced metallothionein IIa to five times higher levels than metallothionein Ig. Of 13 different metals, only iron was altered, exhibiting an 81% decrease in old versus young lenses. CONCLUSIONS Induction of metallothioneins and alpha-crystallin/small heat shock proteins by different metals indicates the presence of metal-specific lens regulatory pathways that are likely to be involved in protection against metal-associated stresses.
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Affiliation(s)
- John R. Hawse
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | | | - Brian Oppermann
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Nancy L. Sheets
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Venkat N. Reddy
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Marc Kantorow
- Department of Biology, West Virginia University, Morgantown, West Virginia
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Ito H, Kamei K, Iwamoto I, Inaguma Y, Kato K. Regulation of the levels of small heat-shock proteins during differentiation of C2C12 cells. Exp Cell Res 2001; 266:213-21. [PMID: 11399049 DOI: 10.1006/excr.2001.5220] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Levels of the small heat-shock proteins (sHSPs) HSP27 and alphaB-crystallin during differentiation of mouse C2C12 cells were determined using specific immunoassays. Increases of these proteins were about 3-fold and 10-fold, respectively. Under the same conditions, however, the level of HSP70 in C2C12 cells barely increased, indicating selective accumulation of HSP27 and alphaB-crystallin with differentiation. While expression of mRNA for alphaB-crystallin was also markedly increased and that for HSP27 was but to a lesser extent, mRNA for HSP70 could barely be detected during differentiation. Activation of the heat-shock factor was not observed, in contrast to the case with heat-stressed undifferentiated cells. Various inhibitors of protein kinases affected the differentiation and the associated increase of sHSPs. Rapamycin, an inhibitor of p70 S6 kinase, completely inhibited the differentiation and suppressed the accumulation of HSP27 and alphaB-crystallin. SB203580, an inhibitor of p38 MAP kinase, also inhibited differentiation, but the accumulation of alphaB-crystallin was rather enhanced. PD98059, an inhibitor of MAP kinase kinase, significantly increased expression of a differentiation marker for muscle cells, creatine kinase M isozyme, as well as accumulation of alphaB-crystallin. These results suggest that accumulation of sHSPs during differentiation of C2C12 cells is regulated in a complex manner.
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Affiliation(s)
- H Ito
- Department of Biochemistry, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, 480-0392, Japan.
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Avivi A, Joel A, Nevo E. The lens protein alpha-B-crystallin of the blind subterranean mole-rat: high homology with sighted mammals. Gene 2001; 264:45-9. [PMID: 11245977 DOI: 10.1016/s0378-1119(00)00603-x] [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: 10/17/2022]
Abstract
Blind subterranean mole rats, Spalax ehrenbergi, retain a subcutaneous, degenerated eye, which is visually non-functional but which does function in circadian entrainment. Crystallins, members of the small heat shock protein family, constitute approximately 90% of the water-soluble proteins of the transparent eye lens and are crucial for its optical properties, but they are also expressed in other tissues. In our attempt to understand the role of the eye in the blind mole-rat, we now describe the cloning, sequencing, and expression of the cDNA of alpha-B-Crystallin from two species of Spalax (S. galili and S. Judaei, with diploid chromosome numbers 2n=52 and 60, respectively). Spalax alpha- B-Crystallin is highly conserved. It is expressed in many tissues of Spalax, among them Spalax eye. The sequence of the cDNA of alpha-B-Crystallin in the eye and in the heart of Spalax is identical. Further studies are essential to clarify the role of this gene in the lens of an atrophied eye of a visually blind mammal.
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Affiliation(s)
- A Avivi
- Laboratory of Molecular Evolution of Animals, Institute of Evolution, University of Haifa, Mt. Carmel, 31905, Haifa, Israel.
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Bajramović JJ, Bsibsi M, Geutskens SB, Hassankhan R, Verhulst KC, Stege GJ, de Groot CJ, van Noort JM. Differential expression of stress proteins in human adult astrocytes in response to cytokines. J Neuroimmunol 2000; 106:14-22. [PMID: 10814778 DOI: 10.1016/s0165-5728(99)00260-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Various lines of evidence suggest a close relationship between heat shock proteins (hsp) and several autoimmune diseases such as arthritis, diabetes and multiple sclerosis. While enhanced expression of hsp in autoimmune diseases is often regarded as a non-specific bystander effect of the inflammatory process, surprisingly little is known on hsp regulation by inflammatory mediators such as cytokines. In this study cytokine-induced expression of hsp60, hsp27 and alphaB-crystallin was studied in cultures of primary human adult astrocytes at the mRNA as well as at the protein level. We show differential hsp expression patterns in response to pro-inflammatory and immunoregulatory cytokines. Hsp60 expression was found to be enhanced in response to cytokines as diverse as IL-1beta, TNF-alpha, IL-4, IL-6 and IL-10. Upregulation of hsp27, however, was primarily induced by immunoregulatory cytokines like IL-4, IL-6 and TGF-beta whereas alphaB-crystallin expression was found to be enhanced by the pro-inflammatory cytokine TNF-alpha only. None of the cytokines studied was able to enhance expression of all three hsp simultaneously. These results show that in human astrocytes induced expression of hsp27 and alphaB-crystallin is dependent on the presence of a defined set of stimuli, while induced expression of hsp60 is a much less selective event. This highly differential pattern of hsp expression in response to inflammatory mediators known to play an important role in the pathogenesis of autoimmune diseases indicates that hsp responses are specific rather than non-specific bystander responses.
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Affiliation(s)
- J J Bajramović
- Division of Immunological and Infectious Diseases, TNO Prevention and Health, Zernikedreef 9, 2333 CK, Leiden, The Netherlands
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12
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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.
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Affiliation(s)
- T Somasundaram
- Jules Stein Eye Institute and Brain Research Institute, UCLA, Los Angeles, California 90095-7000, USA
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13
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Bloemendal M, Bloemendal H. Hydrophobicity and flexibility of alpha A- and alpha B-crystallin are different. Int J Biol Macromol 1998; 22:239-45. [PMID: 9650078 DOI: 10.1016/s0141-8130(98)00021-x] [Citation(s) in RCA: 7] [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
Since the discovery that the lens protein alpha-crystallin is also found in non-lenticular tissues and can function as a chaperone, relatively little attention has been paid to differences in properties between alpha A- and alpha B-crystallin, which form mixed aggregates in the lens but have so far never been found together in other tissues. In this study hydrophobicity and flexibility, properties that are thought to be relevant for chaperone function, are compared for alpha A- and alpha B-crystallin. Hydrophobicity was monitored from sodium dodecylsulphate polyacrylamide gel electrophoresis in the absence and presence of (methyl-substituted) ureas. Flexibilities were calculated from primary structures. Based on literature data also some other properties are compared. The results indicate significant difference in hydrophobicity profile, flexibility of the terminal parts and stability of alpha A- and alpha B-crystallin.
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Affiliation(s)
- M Bloemendal
- Department of Physics and Astronomy, Free University, Amsterdam, The Netherlands.
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Iwaki A, Nagano T, Nakagawa M, Iwaki T, Fukumaki Y. Identification and characterization of the gene encoding a new member of the alpha-crystallin/small hsp family, closely linked to the alphaB-crystallin gene in a head-to-head manner. Genomics 1997; 45:386-94. [PMID: 9344664 DOI: 10.1006/geno.1997.4956] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
alphaB-Crystallin is a member of the alpha-crystallin/small heat shock protein (hsp) family and under various neuropathologic conditions accumulates in reactive astrocytes and degenerating neurons. In the 5'-flanking region of the alphaB-crystallin gene on human chromosome 11q22-q23, where a constitutive DNase I hypersensitive site is located, we identified a gene transcribed in the opposite direction. Analysis of its mRNA structure by RT-PCR and 5'/3'RACE revealed that this gene is composed of two exons and encodes a new member of the alpha-crystallin/small hsp family. This gene was designated the HSPB2 gene by the HMGW Nomenclature Committee. The complete genomic structure of the rat homologue was also determined. Northern blot analysis revealed that the HSPB2 gene is expressed preferentially in skeletal muscle and heart but not in the lens, while the neighboring alphaB-crystallin gene is highly expressed in all three tissues. The two related genes are arranged in a head-to-head manner with an intergenic sequence of less than 1 kb, raising a possibility of shared regulatory elements for their expression.
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Affiliation(s)
- A Iwaki
- Institute of Genetic Information, Kyushu University 18, Fukuoka, 812-82, Japan.
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Boronat S, Richard-Foy H, Piña B. Specific deactivation of the mouse mammary tumor virus long terminal repeat promoter upon continuous hormone treatment. J Biol Chem 1997; 272:21803-10. [PMID: 9268310 DOI: 10.1074/jbc.272.35.21803] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have studied the transcriptional behavior of the mouse mammary tumor virus long repeat (MMTV-LTR) promoter during a prolonged exposure to glucocorticoids. When integrated into XC-derived cells, MMTV-LTR expression reached its maximum during the first day of dexamethasone treatment, but longer exposure to the hormone resulted in the deactivation of the promoter. In contrast, glucocorticoid-responsive resident genes or MMTV-based transiently transfected plasmids maintained or even increased their mRNA levels during the same period of hormone treatment. An integrated chimeric construct containing the hormone-responsive elements from MMTV-LTR but in different sequence context became also deactivated after a prolonged hormone treatment but with a deactivation kinetics significantly slower than constructs containing the entire, chromatin-positioning MMTV-LTR sequence. The decrease on MMTV-LTR-driven transcription was concomitant with a parallel closure of the MMTV-LTR chromatin and with a decrease in glucocorticoid receptor (GR) concentration in the cell. We concluded that the chromatin-organized MMTV-LTR promoter is particularly sensitive to any decrease on GR levels. We propose that chromatin structure may contribute decisively to the differential expression of MMTV-LTR by two mechanisms: limiting MMTV-LTR accessibility to activating transcription factors and accelerating its shutting down upon a decrease on GR levels.
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MESH Headings
- Animals
- Blotting, Western
- Cells, Cultured
- Chromatin/metabolism
- Cricetinae
- Deoxyribonuclease I/metabolism
- Genes, Reporter
- Glucocorticoids/pharmacology
- Kinetics
- Mammary Tumor Virus, Mouse/drug effects
- Mammary Tumor Virus, Mouse/genetics
- Mice
- Promoter Regions, Genetic/drug effects
- RNA, Messenger/metabolism
- Receptors, Glucocorticoid/metabolism
- Repetitive Sequences, Nucleic Acid/drug effects
- Repetitive Sequences, Nucleic Acid/genetics
- Transfection
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Affiliation(s)
- S Boronat
- Departament de Biologia Molecular i Cel.lular, Centre d'Investigació i Desenvolupament, Consejo Superior de Investigaciones Científicas, C/Jordi Girona, 18-26, 08034 Barcelona, Spain
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16
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Macip S, Mezquita C, Mezquita J. Alternative transcriptional initiation and alternative use of polyadenylation signals in the alphaB-crystallin gene expressed in different chicken tissues. Gene 1997; 187:253-7. [PMID: 9099889 DOI: 10.1016/s0378-1119(96)00763-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Overexpression of alphaB-crystallin is associated with numerous neurodegenerative diseases and abnormal cell growth patterns. To study the mechanisms involved in the control of the transcriptional activity of the gene we have characterized its expression in different chicken tissues. The sequence of the alphaB-crystallin cDNA isolated from chicken testis and 6-day-old chick embryo is highly homologous to the duck alphaB-crystallin cDNA and differs from the previously reported chicken lens alphaB-crystallin cDNA in the 5' untranslated region (5'-UTR) and in one amino acid of the coding sequence. Four forms of the alphaB-crystallin cDNA detected in chicken testes arise from the use of alternative transcription initiation sites and alternative polyadenylation signals. The two principal hybridizing bands found in lens and embryonic tissues possess a short 5'-UTR and differ in the length of the 3'-UTR. Forms with longer 5'-UTR are present in testis, muscle, and heart. The use of different start sites and polyadenylation signals could modulate transcriptional activity and the stability of the messages. The expression of the alphaB-crystallin gene decreases from day 6 to day 8 of chick embryogenesis, in parallel with the expression of the polyubiquitin gene UbII.
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Affiliation(s)
- S Macip
- Molecular Genetics Research Group, Faculty of Medicine, University of Barcelona, Spain
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17
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Head MW, Hurwitz L, Goldman JE. Transcription regulation of alpha B-crystallin in astrocytes: analysis of HSF and AP1 activation by different types of physiological stress. J Cell Sci 1996; 109 ( Pt 5):1029-39. [PMID: 8743950 DOI: 10.1242/jcs.109.5.1029] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The coordinated cellular responses to physiological stress are known to be effected in part by the activation of heat-shock factor 1, a transcriptional activator protein capable of binding to, and inducing transcription from genes containing heat shock elements. Other stress responsive signal transduction pathways also exist including the stress activated protein kinase cascade that regulates the activity of the transcription factor AP1. We have examined the expression of the low molecular stress proteins, heat shock protein 27 and alpha B-crystallin in astrocytes in response to physiological stress of different types and asked what component of this induction is effected at the transcriptional level and whether activation of heat shock factor 1 and AP1 might account for these events. We have found that stress regulated induction of alpha B-crystallin has a strong transcriptional component and that it may be effected by at least two different transcriptional mechanisms. In one set of phenomena, represented here by cadmium exposure, alpha B-crystallin and heat shock protein 27 are coordinately regulated and this occurs in the presence of activated heat shock factor 1. In the second series of phenomena, represented here by hypertonic stress, alpha B-crystallin is induced in the absence of heat shock factor activation and in the absence of any corresponding change in heat shock protein 27 expression. Although hypertonic stress does activate an AP1-like binding activity, the AP1 consensus binding site in the alpha B-crystallin promoter does not appear to be a target for this hypertonic stress inducible activity. These data suggest that the hypertonic stress response is effected through a heat shock factor independent mechanism and that hypertonic stress regulated induction of alpha B-crystallin does not directly depend on the SAPK pathway and AP1 activity.
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Affiliation(s)
- M W Head
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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18
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Wistow G, Graham C. The duck gene for alpha B-crystallin shows evolutionary conservation of discrete promoter elements but lacks heat and osmotic shock response. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1263:105-13. [PMID: 7640300 DOI: 10.1016/0167-4781(95)00087-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The gene for alpha Beta-crystallin from a bird (the domestic duck, Anas platyrhynchos) has been cloned and sequenced to allow comparison with its mammalian homologues. The duck gene has the same general structure as those of humans and rodents although, unlike those of mammals, the duck gene has two polyadenylation signals at the 3' end. The most interesting comparisons are in the 5'flanking promoter regions. In contrast to the broad conservation of promoter sequence among mammals, only two significant blocks and a few smaller elements have been conserved during evolution in the more distantly related avian gene. Block 1 (-350/-308) corresponds to alpha BE-2, a functional element defined in the mouse gene. Further downstream, block 2 (-98/-65) shows 27/33 identity among all three species but does not correspond to any previously defined element. Other regions are less well-conserved. In particular, putative heat-shock response elements of the mammalian alpha B-crystallin genes are absent from the duck gene. In contrast to the heat and osmotic stress-inducibility of mouse alpha B-crystallin in NIH 3T3 cells, duck alpha B-crystallin showed no inducibility in duck cells in culture. Thus, although high expression in lens is common to alpha B-crystallin genes in birds and mammals, other modes of expression appear to be taxon-specific.
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Affiliation(s)
- G Wistow
- Section on Molecular Structure and Function LMDB, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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19
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Haynes JI, Gopal-Srivastava R, Frederikse PH, Piatigorsky J. Differential use of the regulatory elements of the alpha B-crystallin enhancer in cultured murine lung (MLg), lens (alpha TN4-1) and muscle (C2C12) cells. Gene 1995; 155:151-8. [PMID: 7536694 DOI: 10.1016/0378-1119(95)00007-s] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The mouse alpha B-crystallin-encoding gene (alpha B-cry) is highly expressed in the lens and expressed to lesser extents in other tissues. Here, we investigated alpha B-cry expression in mouse-lung-derived MLg cells. Two sizes of MLg alpha B-cry transcripts comigrated with alpha B-cry transcripts contained in total and poly(A)+RNA from mouse lung, with preference for the larger species in the MLg cells. Expression of both alpha B-cry promoter/cat reporter gene constructs and alpha B-cry enhancer (nt -427/-259)/herpes simplex virus (HSV) thymidine kinase promoter (ptk)/human growth hormone reporter gene (hGH) constructs was studied in transfected MLg cells and the results compared with those obtained from alpha TN4-1 lens and C2C12 muscle cells. The alpha B-cry enhancer increased activity of the endogenous and tk promoters approx. 2-fold in the MLg cells, in contrast to its 3-7-fold effect in alpha TN4-1 cells and 17-20-fold effect in C2C12 myotubes. Site-specific mutagenesis of the previously identified enhancer control elements, alpha B-E-1 (nt -407 to -397), alpha BE-2 (-360 to -327) and MRF (-300 to -288), decreased enhancer strength in transfected MLg cells. DNase I footprinting showed that MLg nuclear proteins occupy only alpha BE-1 and alpha BE-2. Previous data have shown that lens cells use alpha BE-1, alpha BE-2 and alpha BE-3, while muscle cells use, in addition, the muscle regulatory factor-binding site (MRF). Thus, the present experiments correlate tissue-specific enhancer strength and the number of control elements utilized.
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Affiliation(s)
- J I Haynes
- Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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20
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Frederikse PH, Dubin RA, Haynes JI, Piatigorsky J. Structure and alternate tissue-preferred transcription initiation of the mouse alpha B-crystallin/small heat shock protein gene. Nucleic Acids Res 1994; 22:5686-94. [PMID: 7838723 PMCID: PMC310134 DOI: 10.1093/nar/22.25.5686] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have determined the complete nucleotide sequence (-865 to +3515) of the murine alpha B-crystallin/small heat shock protein gene, a major soluble protein of the vertebrate eye lens. Its 3 exon/2 intron structure is identical to that of the rat, hamster and human gene, with the exons being much more conserved than the introns. Previous reports indicated that there are two sizes of alpha B-crystallin mRNA; a larger alpha B-crystallin mRNA predominates in the lung and brain and is also found in low levels in most other tissues (except in lens and liver), while a smaller alpha B-crystallin mRNA exists at a high level in the lens and in variable amounts elsewhere. Sequence analysis suggests that secondary structure in the 5' untranslated sequence of the longer mRNA has led to difficulty in mapping the transcription initiation site of the longer transcript. Here we provide evidence by primer extension, S1 nuclease protection, and PCR (polymerase chain reaction) experiments for a transcription initiation site in the murine lung and brain at position -474. We also detected the utilization of the -474 initiation site in lens and of the +1 site in lung and brain, indicating that the tissue preference for these sites is not absolute. In vitro transcription experiments revealed that cell-free HeLa nuclear extracts specifically initiate transcription at the -474 and +1 sites. alpha B-crystallin was immunocytochemically localized to the bronchioles of the lung. Thus, regulation of alpha B-crystallin/small heat shock protein expression involves the utilization of tissue-preferred transcription initiation sites.
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Affiliation(s)
- P H Frederikse
- Laboratory of Molecular and Developmental Biology, National Eye Institute, NIH, Bethesda, MD 20892
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