1
|
Zagorski J, Marchick MR, Kline JA. Rapid clearance of circulating haptoglobin from plasma during acute pulmonary embolism in rats results in HMOX1 up-regulation in peripheral blood leukocytes. J Thromb Haemost 2010; 8:389-96. [PMID: 19943874 DOI: 10.1111/j.1538-7836.2009.03704.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Acute pulmonary embolism (PE) causes pulmonary hypertension (PH) via several mechanisms including pulmonary vasospasm. We hypothesize that PE with associated PH leads to alterations in plasma protein concentrations indicative of disease severity and prognosis. OBJECTIVE To identify plasma proteins altered in abundance by PE in rats. METHODS Plasma samples were obtained from rats at 2, 6 and 18 h after experimental PE produced with intrajugular injection of polystyrene beads at three different levels of severity (mild, moderate and severe). Total plasma protein was separated using two-dimensional sodium dodecylsulfate-polyacrylamide gel electrophoresis (2D SDS-PAGE) and candidate protein spots altered in expression by PE were identified by mass spectroscopy. Haptoglobin identity and amount was verified by western blot analysis. RESULTS The PE model produced a dose-dependent increase in right ventricular systolic pressure (RVSP) (mmHg) at 2 h: mild 39+/-1.7, moderate 40+/-1.8 and severe 51+/-1.3 mmHg, coincident with significant increases in free plasma (hemoglobin). Combined 2D SDS-PAGE and Western blot analysis indicated time- and dose-dependant loss of plasma haptoglobin levels in response to acute PE. Haptoglobin (HP) was essentially absent from plasma within 2 h of severe PE. Clearance of HP from plasma was accompanied by increased expression of heme oxygenase-1 (hmox1) in peripheral blood leukocytes and in HMOX1 enzyme activity in the liver. CONCLUSIONS PE that causes pulmonary hypertension is associated with haptoglobin depletion and up-regulation of HMOX1 enzyme.
Collapse
MESH Headings
- Acute Disease
- Animals
- Blotting, Western
- Disease Models, Animal
- Down-Regulation
- Electrophoresis, Polyacrylamide Gel
- Haptoglobins/metabolism
- Heme Oxygenase (Decyclizing)/blood
- Hemolysis
- Hypertension, Pulmonary/blood
- Hypertension, Pulmonary/enzymology
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/physiopathology
- Leukocytes, Mononuclear/enzymology
- Liver/enzymology
- Male
- Mass Spectrometry
- Proteomics/methods
- Pulmonary Embolism/blood
- Pulmonary Embolism/complications
- Pulmonary Embolism/enzymology
- Pulmonary Embolism/physiopathology
- Rats
- Rats, Sprague-Dawley
- Severity of Illness Index
- Time Factors
- Up-Regulation
- Vascular Resistance
- Ventricular Function, Right
- Ventricular Pressure
Collapse
Affiliation(s)
- J Zagorski
- Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC 28203, USA
| | | | | |
Collapse
|
2
|
Mitchell A, Zagorski J, Kruse L, Kline J. Enhanced Resolution of Human Plasma Proteins by Proteomic Separation and 2-Dimensional Gel Electrophoresis. Ann Emerg Med 2005. [DOI: 10.1016/j.annemergmed.2005.06.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
3
|
Fazal N, Shamim M, Zagorski J, Choudhry MA, Ravindranath T, Sayeed MM. CINC blockade prevents neutrophil Ca(2+) signaling upregulation and gut bacterial translocation in thermal injury. Biochim Biophys Acta 2000; 1535:50-9. [PMID: 11113631 DOI: 10.1016/s0925-4439(00)00082-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this study, we have evaluated the role of cytokine-induced neutrophil chemoattractant (CINC), in the upregulation of neutrophil Ca(2+) signaling in neutrophils from thermally injured rats treated with anti-CINC antibody. Additionally, we have determined the effect of the treatment with CINC antibody on the accumulation of activated neutrophils in the intestinal wall, and the effect of such accumulation on gut bacterial translocation. Measurements of myeloperoxidase (MPO) activity and immunohistochemical localization of neutrophils determined neutrophil sequestration in the rat intestine. Agar culture analyses and a specific Escherichia coli beta-galactosidase gene polymerase chain reaction was carried out to detect gut indigenous bacterial invasion into intestinal wall and extraintestinal mesenteric lymph nodes (MLN). The results showed that pretreatment of rats with anti-CINC antibody attenuated the thermal injury-induced enhancement in [Ca(2+)](i) responses in neutrophils both in the basal and Formyl-Met-Leu-Phe stimulated conditions. Moreover, treatment with the CINC antibody decreased neutrophil infiltration into the gut and attenuated thermal injury-caused translocation of bacteria into the MLN.
Collapse
Affiliation(s)
- N Fazal
- Department of Surgery, Loyola University Chicago Medical Center, Maywood, Illinois 60153, USA
| | | | | | | | | | | |
Collapse
|
4
|
Bhatia M, Brady M, Zagorski J, Christmas SE, Campbell F, Neoptolemos JP, Slavin J. Treatment with neutralising antibody against cytokine induced neutrophil chemoattractant (CINC) protects rats against acute pancreatitis associated lung injury. Gut 2000; 47:838-44. [PMID: 11076884 PMCID: PMC1728153 DOI: 10.1136/gut.47.6.838] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Lung injury manifest clinically as adult respiratory distress syndrome (ARDS) is a common cause of morbidity and mortality following acute pancreatitis (AP). Neutrophils play a critical role in the progression of AP to ARDS. C-x-C chemokines are potent neutrophil chemoattractants and activators and have been implicated in AP. AIMS To evaluate the effect of blocking the C-x-C chemokine, cytokine induced neutrophil chemoattractant (CINC), in AP on pancreatic inflammation and the associated lung injury in rats. METHODS AP was induced by hourly intraperitoneal injections of caerulein. Goat anti-CINC antibody was administered either before or after starting caerulein injections to evaluate the prophylactic and therapeutic effects, respectively. Severity of AP was determined by measuring plasma amylase, pancreatic water content, and pancreatic myeloperoxidase (MPO) activity as a measure of neutrophil sequestration in the pancreas. Lung injury was determined by measurement of pulmonary microvascular permeability and lung MPO activity. RESULTS Treatment with anti-CINC antibody had little effect on caerulein induced pancreatic damage. However, it reduced the caerulein mediated increase in lung MPO activity as well as lung microvascular permeability when administered either prophylactically (lung MPO (fold increase over control): 1.53 (0.21) v. 3.30 (0.46), p<0.05; microvascular permeability (L/P%): 0.42 (0.07) v. 0.77 (0.11), p<0.05) or therapeutically (lung MPO (fold increase over control): 2.13 (0.10) v 4.42 (0.65), p<0.05; microvascular permeability (L/P%): 0.31 (0.05) v 0.79 (0.13), p<0.05). CONCLUSION Treatment with anti-CINC antibody afforded significant protection against pancreatitis associated lung injury. These results suggest that CINC plays an important role in the systemic inflammatory response in AP.
Collapse
Affiliation(s)
- M Bhatia
- Department of Surgery, University of Liverpool, Royal Liverpool University Hospital, Liverpool, UK.
| | | | | | | | | | | | | |
Collapse
|
5
|
Song X, Zeng L, Pilo CM, Zagorski J, Wahl SM. Inhibition of bacterial cell wall-induced leukocyte recruitment and hepatic granuloma formation by TGF-beta gene transfer. J Immunol 1999; 163:4020-6. [PMID: 10491005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Intraperitoneal injection of streptococcal cell walls (SCW) into Lewis rats results in dissemination of SCW to the liver, spleen, bone marrow, and peripheral joints. The uptake of SCW by Kupffer cells in the liver initiates a chain of events largely mediated by T lymphocytes and macrophages. Local synthesis and secretion of cytokines and growth factors in response to the persistent SCW lead to the evolution and maintenance of a chronic T cell-dependent granulomatous response and result in granuloma formation and irreversible hepatic fibrosis. In an attempt to impede the development of the chronic granulomatous lesions in the liver, we injected a plasmid DNA encoding TGF-beta 1 i.m. to the SCW animals to determine the effect of TGF-beta 1 gene transfer on the course of liver inflammation and fibrosis. A single injection of plasmid DNA encoding TGF-beta 1 resulted in virtual abolition of the development of the SCW-induced hepatic granuloma formation and matrix expansion. TGF-beta 1 DNA not only reduced key proinflammatory cytokines including TNF-alpha, IL-1 beta, IFN-gamma, and IL-18, but also inhibited both CXC and CC chemokine production, thereby blocking inflammatory cell recruitment and accumulation in the liver. Moreover, TGF-beta 1 gene delivery inhibited its own expression in the liver tissue, which is otherwise up-regulated in SCW-injected animals. Our study suggests that TGF-beta 1 gene transfer suppresses hepatic granuloma formation by blocking the recruitment of inflammatory cells to the liver, and thus may provide a new approach to the control of hepatic granulomatous and fibrotic diseases.
Collapse
Affiliation(s)
- X Song
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
6
|
Davenpeck KL, Zagorski J, Schleimer RP, Bochner BS. Lipopolysaccharide-induced leukocyte rolling and adhesion in the rat mesenteric microcirculation: regulation by glucocorticoids and role of cytokines. J Immunol 1998; 161:6861-70. [PMID: 9862718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A common side effect of high dose glucocorticoid therapy is increased susceptibility to bacterial infection, an effect that is in part mediated through inhibition of leukocyte recruitment to infected areas. However, the sites at which glucocorticoids act to prevent the multistep process of leukocyte recruitment have not been fully established. In this study, the effects of the glucocorticoid dexamethasone (DEX) on leukocyte-endothelial interactions, in response to bacterial LPS, were examined utilizing a model of rat mesenteric intravital microscopy. Pretreatment of rats with DEX (0.5 mg/kg) for 18 h or 30 min before stimulation with LPS significantly inhibited LPS-induced leukocyte rolling and adhesion in mesenteric postcapillary venules. Pretreatment with DEX also inhibited LPS-induced changes in expression of L-selectin and a shared epitope of CD11b/c on circulating neutrophils. These effects of DEX may be due to DEX inhibition of IL-1, TNF, and cytokine-induced neutrophil chemoattractant-1 (CINC-1) generation, since antagonists to these mediators were able to mimic DEX effects on leukocyte-endothelial interactions and circulating leukocyte phenotype. These data indicate that inhibition of cytokine- and chemokine-induced leukocyte-endothelial interactions may be a primary mechanism by which glucocorticoids inhibit leukocyte recruitment to bacterial agents and thus increase susceptibility to infection.
Collapse
Affiliation(s)
- K L Davenpeck
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | | | | | | |
Collapse
|
7
|
Kennedy T, Ghio AJ, Reed W, Samet J, Zagorski J, Quay J, Carter J, Dailey L, Hoidal JR, Devlin RB. Copper-dependent inflammation and nuclear factor-kappaB activation by particulate air pollution. Am J Respir Cell Mol Biol 1998; 19:366-78. [PMID: 9730864 DOI: 10.1165/ajrcmb.19.3.3042] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Particulate air pollution causes increased cardiopulmonary morbidity and mortality, but the chemical determinants responsible for its biologic effects are not understood. We studied the effect of total suspended particulates collected in Provo, Utah, an area where an increase in respiratory symptoms in relation to levels of particulate pollution has been well documented. Provo particulates caused cytokine-induced neutrophil chemoattractant-dependent inflammation of rat lungs. Provo particulates stimulated interleukin-6 (IL-6) and IL-8 production, increased IL-8 messenger RNA (mRNA) and enhanced expression of intercellular adhesion molecule-1 (ICAM-1) in cultured BEAS-2B cells, and stimulated IL-8 secretion in primary cultures of human bronchial epithelium. Cytokine secretion was preceded by activation of the transcription factor nuclear factor-kappaB (NF-kappaB) and was reduced by treatment of cultures with superoxide dismutase, deferoxamine, or N-acetylcysteine. These biologic effects were replicated by culturing BEAS cells with quantities of Cu2+ found in Provo extract. IL-8 secretion by BEAS cells could be modified by addition of normal constituents of airway lining fluid to the culture medium. Mucin significantly reduced IL-8 secretion, and ceruloplasmin significantly increased IL-8 secretion and activation of NF-kappaB. These findings suggest that copper ions may cause some of the biologic effects of inhaled particulate air pollution in the Provo region of the United States, and may provide an explanation for the sensitivity of asthmatic individuals to Provo particulates that has been observed in epidemiologic studies.
Collapse
Affiliation(s)
- T Kennedy
- Department of Internal Medicine, Carolinas Medical Center, Charlotte; National Health and Environmental Effects Research Laboratory, Environmental Protection Agency, Research Triangle Park, NC, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Fan J, Marshall JC, Jimenez M, Shek PN, Zagorski J, Rotstein OD. Hemorrhagic shock primes for increased expression of cytokine-induced neutrophil chemoattractant in the lung: role in pulmonary inflammation following lipopolysaccharide. J Immunol 1998; 161:440-7. [PMID: 9647254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Recent studies have suggested that hemorrhagic shock followed by resuscitation renders patients more susceptible to lung injury by priming for an exaggerated response to a second stimulus, the so-called "two-hit" hypothesis. We investigated the role of C-X-C chemokines in mediating the augmented lung inflammation in response to LPS following resuscitated shock. In a rodent model, animals exposed to antecedent shock exhibited enhanced lung neutrophil sequestration and transpulmonary albumin flux in response to intratracheal LPS. This effect correlated with an exaggerated expression of cytokine-induced neutrophil chemoattractant (CINC) protein and mRNA, but not macrophage-inflammatory protein 2. Strategies designed to inhibit CINC, both anti-CINC Ab and supplementation with the antioxidant N-acetyl-cysteine, prevented the enhanced neutrophil sequestration, suggesting that CINC played a central role in the enhanced leukocyte accumulation following shock plus LPS treatment. Shock alone increased lung nuclear factor-kappaB expression and augmented the response to LPS. Prevention of this effect by N-acetylcysteine supplementation of the resuscitation fluid implicates a role for oxidant stress in the priming for lung inflammation following shock. Finally, alveolar macrophages recovered from shock-resuscitated animals released more CINC protein in vitro in response to LPS than macrophages from sham animals. Considered together, these findings show that augmented release of CINC, in part from primed alveolar macrophages, contributes significantly to the enhanced lung leukosequestration and transpulmonary albumin flux in response to LPS following resuscitated shock.
Collapse
Affiliation(s)
- J Fan
- Department of Surgery, The Toronto Hospital, University of Toronto, Ontario, Canada.
| | | | | | | | | | | |
Collapse
|
9
|
Zagorski J, Wahl SM. Inhibition of acute peritoneal inflammation in rats by a cytokine-induced neutrophil chemoattractant receptor antagonist. J Immunol 1997; 159:1059-62. [PMID: 9233596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cytokine-induced neutrophil chemoattractant (CINC), a member of the IL-8 superfamily of chemokines, is one rat homologue of the three human GRO proteins. Neutralizing Abs against CINC have been shown previously to be efficacious in several models of inflammation, indicating that CINC is an important proinflammatory mediator in vivo. By introducing the N-terminal mutation delta1-5,ELR>AAR into CINC, we have developed a rat alpha-chemokine receptor antagonist (ra) analogous to a previously described mutant of human IL-8. Bacterially expressed CINCra had no chemotactic activity itself, but completely blocked the activity of physiologic concentrations of CINC when used as an antagonist in vitro. Inhibition by CINCra was specific, since it had approximately 10-fold less antagonist activity on the related, but distinct rat alpha-chemokine macrophage-inflammatory protein 2. When coinjected with zymosan into the peritoneal cavities of Lewis rats, 100 microg of CINCra inhibited neutrophil influx by approximately 40%, which was comparable with inhibition caused by polyclonal anti-CINC Abs.
Collapse
Affiliation(s)
- J Zagorski
- Oral Infection and Immunity Branch, National Institute of Dental Research, Bethesda, MD 20892, USA.
| | | |
Collapse
|
10
|
Zagorski J, Wahl SM. Inhibition of acute peritoneal inflammation in rats by a cytokine-induced neutrophil chemoattractant receptor antagonist. The Journal of Immunology 1997. [DOI: 10.4049/jimmunol.159.3.1059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Cytokine-induced neutrophil chemoattractant (CINC), a member of the IL-8 superfamily of chemokines, is one rat homologue of the three human GRO proteins. Neutralizing Abs against CINC have been shown previously to be efficacious in several models of inflammation, indicating that CINC is an important proinflammatory mediator in vivo. By introducing the N-terminal mutation delta1-5,ELR>AAR into CINC, we have developed a rat alpha-chemokine receptor antagonist (ra) analogous to a previously described mutant of human IL-8. Bacterially expressed CINCra had no chemotactic activity itself, but completely blocked the activity of physiologic concentrations of CINC when used as an antagonist in vitro. Inhibition by CINCra was specific, since it had approximately 10-fold less antagonist activity on the related, but distinct rat alpha-chemokine macrophage-inflammatory protein 2. When coinjected with zymosan into the peritoneal cavities of Lewis rats, 100 microg of CINCra inhibited neutrophil influx by approximately 40%, which was comparable with inhibition caused by polyclonal anti-CINC Abs.
Collapse
Affiliation(s)
- J Zagorski
- Oral Infection and Immunity Branch, National Institute of Dental Research, Bethesda, MD 20892, USA.
| | - S M Wahl
- Oral Infection and Immunity Branch, National Institute of Dental Research, Bethesda, MD 20892, USA.
| |
Collapse
|
11
|
Koto H, Salmon M, Huang TJ, Zagorski J, Chung KF. Role of cytokine-induced neutrophil chemoattractant (CINC) in ozone-induced airway inflammation and hyperresponsiveness. Am J Respir Crit Care Med 1997; 156:234-9. [PMID: 9230754 DOI: 10.1164/ajrccm.156.1.9606095] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cytokine-induced neutrophil chemoattractant (CINC) is a rat chemokine with potent chemoattractant effects on neutrophils. We determined the involvement of CINC in ozone-induced airway neutrophilia and bronchial hyperresponsiveness (BHR) in the rat. We found a marked increase in lung CINC messenger RNA (mRNA) within 2 h after cessation of ozone exposure (1 ppm for 3 h), as measured by Northern blot analysis, whereas rats exposed to room air had no detectable CINC mRNA. Ozone exposure induced a significant neutrophilia in bronchoalveolar lavage fluid (BALF) at 24 h after exposure (air-exposed rats: 4.2 +/- 2.0 x 10(4), versus ozone-exposed rats: 16.1 +/- 3.7 x 10(4)); prior treatment with a goat anti-CINC antibody (1 mg, intravenously) suppressed the neutrophilia (3.1 +/- 0.9 x 10(4)). When administered intratracheally, the antibody (230 micrograms) partially inhibited the influx of neutrophils. The increase in bronchial responsiveness to acetylcholine observed after ozone exposure was not inhibited by the anti-CINC antibody. The anti-CINC antibody (1 mg, intravenously) also inhibited BALF neutrophilia induced by exposure to a higher concentration of ozone (3 ppm, 3 h), without an effect on BHR. CINC is an important chemokine causing ozone-induced neutrophil chemoattraction, but is not involved in the induction of ozone-induced BHR. The neutrophil is unlikely to contribute to BHR in this model.
Collapse
Affiliation(s)
- H Koto
- Department of Thoracic Medicine, Imperial College of Science, Technology and Medicine, London, England
| | | | | | | | | |
Collapse
|
12
|
Yamasaki Y, Matsuo Y, Zagorski J, Matsuura N, Onodera H, Itoyama Y, Kogure K. New therapeutic possibility of blocking cytokine-induced neutrophil chemoattractant on transient ischemic brain damage in rats. Brain Res 1997; 759:103-11. [PMID: 9219868 DOI: 10.1016/s0006-8993(97)00251-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Earlier we indicated that neutrophilic invasion into cerebral parenchyma is an important step in rat cerebral ischemia-reperfusion injury and the production of chemotactic factors, cytokine-induced neutrophil chemoattractant (CINC) precede the neutrophilic invasion. The aim of the present study was to evaluate the role of CINC production and the therapeutic possibility of blocking CINC activity in the transient ischemic brain damage in rats. Focal transient ischemia was produced by intraluminal occlusion of the right middle cerebral artery for 60 min. An enzyme immunoassay was used to measure the brain concentration of CINC and myeloperoxidase activity in ischemic areas was measured as a marker of neutrophilic accumulation. An immunohistochemical staining technique was used to detect the immunopositive cells for anti-CINC antibody. Further, application of anti-CINC antibody or anti-neutrophil antibody to rats was used to evaluate the role of CINC production. In ischemic areas, CINC production was detected and peaked 12 h after reperfusion, which followed 60 min of ischemia. Intraperitoneal injection of anti-neutrophil antibody 24 h before and immediately after reperfusion significantly reduced the brain water content and partially reduced the CINC production in ischemic areas. Further, immunohistochemical staining showed that anti-CINC antibody was found on the endothelial surface of venules and on parts of neutrophils that had invaded the ischemic area 6 to 24 h after reperfusion. Also, treatment with anti-CINC antibody reduced ischemic edema formation 24 h after reperfusion and the size of infarction areas 7 days after reperfusion. It thus appears that CINC, mainly produced by endothelium activated by factors released from neutrophils, plays an important role in ischemic brain damage. Furthermore, the blocking of CINC activity with antibody suggests an immuno-therapeutic approach to the treatment of stroke patients.
Collapse
Affiliation(s)
- Y Yamasaki
- Hanno Research Center, Taiho Pharmaceutical Co. Ltd., Hanno City, Saitama, Japan
| | | | | | | | | | | | | |
Collapse
|
13
|
Wu X, Dolecki GJ, Sherry B, Zagorski J, Lefkowith JB. Chemokines are expressed in a myeloid cell-dependent fashion and mediate distinct functions in immune complex glomerulonephritis in rat. The Journal of Immunology 1997. [DOI: 10.4049/jimmunol.158.8.3917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Using anti-glomerular basement membrane nephritis in rats, we investigated the mechanisms underlying in situ chemokine expression and the in vivo function of these cytokines during the acute phase of this model. We observed that CXC chemokine expression was monophasic and paralleled neutrophil (PMN) influx, whereas CC chemokine expression was biphasic with peaks coinciding with the influx of PMNs and macrophages (Mphi). The initial peak of chemokine expression was attenuated by decomplementation, neutropenia, and leukopenia, while the latter peak was attenuated only by leukopenia and augmented in the accelerated form of this disease model, corresponding to an increase in Mphi influx. Differential expression of chemokines by PMNs and Mphi was not an intrinsic property of these cells, as these leukocytes expressed similar profiles of chemokines in vitro. Immunostaining for Mphi inflammatory protein-1alpha, a CC chemokine, in acute nephritis validated that expression during acute nephritis was accompanied by local protein production. Moreover, neutralizing Ab to Mphi inflammatory protein-1alpha attenuated the acute phase proteinuria, but not the accompanying influx of PMNs. Neutralizing Ab to cytokine-induced neutrophil chemoattractant (a CXC chemokine), in comparison, inhibited both PMN influx and proteinuria. A combination of both Abs was not significantly more effective than either alone. In sum, the influx of myeloid cells is necessary for local chemokine expression in anti-glomerular basement membrane nephritis, although the differential expression of CXC and CC chemokines must involve additional factors. CXC and CC chemokines also mediate distinct, but overlapping, pathophysiologic roles in the acute phase of this model.
Collapse
Affiliation(s)
- X Wu
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - G J Dolecki
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - B Sherry
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - J Zagorski
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - J B Lefkowith
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| |
Collapse
|
14
|
Wu X, Dolecki GJ, Sherry B, Zagorski J, Lefkowith JB. Chemokines are expressed in a myeloid cell-dependent fashion and mediate distinct functions in immune complex glomerulonephritis in rat. J Immunol 1997; 158:3917-24. [PMID: 9103462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Using anti-glomerular basement membrane nephritis in rats, we investigated the mechanisms underlying in situ chemokine expression and the in vivo function of these cytokines during the acute phase of this model. We observed that CXC chemokine expression was monophasic and paralleled neutrophil (PMN) influx, whereas CC chemokine expression was biphasic with peaks coinciding with the influx of PMNs and macrophages (Mphi). The initial peak of chemokine expression was attenuated by decomplementation, neutropenia, and leukopenia, while the latter peak was attenuated only by leukopenia and augmented in the accelerated form of this disease model, corresponding to an increase in Mphi influx. Differential expression of chemokines by PMNs and Mphi was not an intrinsic property of these cells, as these leukocytes expressed similar profiles of chemokines in vitro. Immunostaining for Mphi inflammatory protein-1alpha, a CC chemokine, in acute nephritis validated that expression during acute nephritis was accompanied by local protein production. Moreover, neutralizing Ab to Mphi inflammatory protein-1alpha attenuated the acute phase proteinuria, but not the accompanying influx of PMNs. Neutralizing Ab to cytokine-induced neutrophil chemoattractant (a CXC chemokine), in comparison, inhibited both PMN influx and proteinuria. A combination of both Abs was not significantly more effective than either alone. In sum, the influx of myeloid cells is necessary for local chemokine expression in anti-glomerular basement membrane nephritis, although the differential expression of CXC and CC chemokines must involve additional factors. CXC and CC chemokines also mediate distinct, but overlapping, pathophysiologic roles in the acute phase of this model.
Collapse
Affiliation(s)
- X Wu
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | | | | | | |
Collapse
|
15
|
Hybertson BM, Bursten SL, Leff JA, Lee YM, Jepson EK, Dewitt CR, Zagorski J, Cho HG, Repine JE. Lisofylline prevents leak, but not neutrophil accumulation, in lungs of rats given IL-1 intratracheally. J Appl Physiol (1985) 1997; 82:226-32. [PMID: 9029220 DOI: 10.1152/jappl.1997.82.1.226] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Interleukin-1 (IL-1) is increased in lung lavages from patients with the acute respiratory distress syndrome, and administering IL-1 intratracheally causes neutrophil accumulation and a neutrophil-dependent oxidative leak in lungs of rats. In the present study, we found that rats pretreated intraperitoneally with lisofylline [(R)-1-(5-hydroxyhexyl)-3, 7-dimethylxanthine (LSF)], an inhibitor of lysophosphatidic acid acyl transferase, which reduces the production of unsaturated phosphatidic acid species, did not develop the lung leak or the related ultrastructural abnormalities that occur after intratracheal administration of IL-1. However, rats pretreated with LSF and then given IL-1 intratracheally did develop the same elevations of lung lavage cytokine-induced neutrophil chemoattractant (CINC) levels and the same increased numbers of lung lavage neutrophils as rats given IL-1 intratracheally. Lungs of rats given IL-1 intratracheally also had increased unsaturated phosphatidic acid and free acyl (linoleate, linolenate) concentrations compared with untreated rats, and these lipid responses were prevented by pretreatment of LSF. Our results reveal that LSF decreases lung leak and lung lipid alterations without decreasing neutrophil accumulation or lung lavage CINC increases in rats given IL-1 intratracheally.
Collapse
Affiliation(s)
- B M Hybertson
- Webb-Waring Institute for Biomedical Research, University of Colorado Health Sciences Center, Denver 80262, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
Cytokine-induced neutrophil chemoattractant (CINC) is a member of the chemokine alpha sub-family. It is induced in rats by tumor necrosis factor-alpha (TNF-alpha), interleukin-1, and lipopolysaccharide and is implicated in neutrophil infiltration in response to inflammatory stimuli. We tested the hypothesis that pretreatment with anti-CINC antibody or by cobra venom factor attenuates hepatic neutrophil accumulation induced by a 90 min infusion of Escherichia coli endotoxin. Changes in the expression of CD11b/c and CD18 and in plasma TNF-alpha levels were also investigated. Cultured hepatocytes and Kupffer cells of endotoxic rats produced significantly more CINC than those of saline-infused controls. CINC generation by Kupffer cells was much lower than generation by hepatocytes. Pretreatment with anti-CINC antibody or cobra venom factor significantly reduced hepatic neutrophil sequestration, but did not affect the up-regulation of CD11b/c and CD18 expression on liver-sequestered neutrophils or plasma TNF-alpha levels. We conclude that CINC-mediated hepatic neutrophil accumulation may not be necessarily associated with up-regulation of neutrophil adhesion molecules or elevated circulating TNF-alpha levels. Attenuation of hepatic neutrophil sequestration by anti-CINC antibody is likely based on blocking of the chemotactic activity of CINC and thus diminishing the chemotactic gradient established in the liver.
Collapse
Affiliation(s)
- P Zhang
- Department of Physiology, Louisiana State University Medical Center, New Orleans 70112-1393, USA
| | | | | | | |
Collapse
|
17
|
Abstract
Human GRO alpha, GRO beta, and GRO gamma are neutrophil chemoattractants structurally related to IL-8 and compete with IL-8 for binding to IL-8 receptors on neutrophils. These proteins are part of a large superfamily of chemotactic cytokines, the "chemokines," members of which share striking structural similarities. We have expressed GRO cDNA's in Escherichia coli as fusions to the MalE gene product, maltose-binding protein (MBP), in a way that allows separation of GRO and MBP moieties by factor Xa cleavage. GRO beta and GRO gamma expressed in bacteria were active in in vitro chemotaxis assays and were as effective as IL-8 in inducing chemotactic migration of neutrophils. Recombinant GRO beta was chemotactic rather than chemokinetic when tested by checkerboard analysis while GRO gamma showed evidence of chemokinetic as well as chemotactic activity. The activities of GRO beta and GRO gamma were not species-specific as both proteins were active on rat as well as human neutrophils and were inhibitable by antibodies raised against CINC, the rat GRO homolog. These data indicate that the MBP fusion protein expression system provides a rapid and simple method for obtaining large quantities of members of the chemokine protein family for biological uses.
Collapse
Affiliation(s)
- J Zagorski
- Department of Health Sciences, Monsanto Company, St. Louis, Missouri 63167
| | | |
Collapse
|
18
|
Crippes BA, Zagorski J, Carr LS, Wittwer AJ, Dolecki GJ, De Larco JE. Investigation of possible autocrine functions for rat GRO/CINC (cytokine-induced neutrophil chemoattractant). J Cell Physiol 1993; 156:412-20. [PMID: 8344995 DOI: 10.1002/jcp.1041560225] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Rat cytokine-induced neutrophil chemoattractant (CINC) is an eight kilodalton polypeptide originally purified from media conditioned by interleukin-1 beta stimulated 52E, an epithelioid clone derived from normal rat kidney (NRK) cells. Using a fibroblastic clone of the NRK cells, 49F, we found expression of the CINC gene to be induced by either serum or cytokines in growth-arrested cultures within 1 hour of stimulation. There was no observable CINC expression in exponentially growing cells in the absence of cytokine stimulation. CINC protein had no significant effect on 3H-thymidine incorporation or growth rate of NRK49F. We have observed that CINC is constitutively produced by some transformed NRK cells, clone RC20, suggesting an association with the expression of a transformed phenotype. Unlike the parent 49F, RC20 cells are capable of growth in soft agar and serum-free media and form highly metastatic tumors in nude mice. We have examined the possible autocrine functions of CINC and its possible links to the expression of the transformed phenotype by these cells. The use of a blocking CINC polyclonal antibody demonstrated that CINC did not function as an autocrine growth factor for RC20. Though CINC is a potent chemoattractant for neutrophils, it did not induce migration of either RC20 or 49F cells. CINC only moderately promoted adhesion of RC20 cells when used as a matrix protein. These data do not support the hypothesis that production of CINC by the RC20 cells provides an obvious advantage for the transformed cells constitutively producing it.
Collapse
Affiliation(s)
- B A Crippes
- Department of Health Sciences, Monsanto Corporate Research, Monsanto Company, St. Louis, Missouri 63198
| | | | | | | | | | | |
Collapse
|
19
|
Wittwer AJ, Carr LS, Zagorski J, Dolecki GJ, Crippes BA, De Larco JE. High-level expression of cytokine-induced neutrophil chemoattractant (CINC) by a metastatic rat cell line: purification and production of blocking antibodies. J Cell Physiol 1993; 156:421-7. [PMID: 8344996 DOI: 10.1002/jcp.1041560226] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Significant levels of cytokine-induced neutrophil chemoattractant (CINC) were found in serum-free medium conditioned by a highly metastatic rat cell line, RC20. To study CINC's role in inflammation and metastasis, CINC was purified from this source for use in in vitro assays and for antibody production in goats and rabbits. CINC was a potent chemoattractant for rat neutrophils (EC-50 0.5 nM). A fusion protein of glutathione-S-transferase and CINC (GST-CINC) was produced in E. coli. Anti-CINC polyclonal IgG was purified from immune goat and rabbit sera by protein A and GST-CINC affinity chromatography. Both goat and rabbit anti-CINC antibody preparations at 4 micrograms/mL (an 11-fold molar excess) were found to completely block the activity of 2.5 nM CINC in a rat neutrophil chemotaxis assay. These antibodies have been used to develop a sensitive immunoassay for CINC. The availability of large amounts of affinity-purified blocking anti-CINC antibody will allow investigations into the role played by CINC in rodent inflammation models and in the metastasis of RC20 cells.
Collapse
MESH Headings
- Animals
- Antibodies/isolation & purification
- Antibodies/metabolism
- Base Sequence
- Cell Line, Transformed
- Chemokines, CXC
- Chemotactic Factors/analysis
- Chemotactic Factors/genetics
- Chemotactic Factors/immunology
- Chemotaxis, Leukocyte/physiology
- Chromatography, Affinity
- Chromatography, High Pressure Liquid
- Culture Media, Conditioned/analysis
- Culture Media, Conditioned/pharmacology
- Culture Media, Serum-Free/analysis
- Culture Media, Serum-Free/pharmacology
- DNA/genetics
- Electrophoresis, Polyacrylamide Gel
- Enzyme-Linked Immunosorbent Assay
- Growth Substances/analysis
- Growth Substances/genetics
- Growth Substances/immunology
- Inflammation/pathology
- Intercellular Signaling Peptides and Proteins
- Kidney/chemistry
- Kidney/metabolism
- Kidney/pathology
- Molecular Sequence Data
- Neoplasm Metastasis/pathology
- Neutrophils/physiology
- Rats
- Recombinant Proteins/pharmacology
Collapse
Affiliation(s)
- A J Wittwer
- Department of Health Sciences, Monsanto Corporate Research, Monsanto Company, St. Louis, Missouri 63198
| | | | | | | | | | | |
Collapse
|
20
|
Zagorski J, DeLarco JE. Rat CINC (cytokine-induced neutrophil chemoattractant) is the homolog of the human GRO proteins but is encoded by a single gene. Biochem Biophys Res Commun 1993; 190:104-10. [PMID: 8422237 DOI: 10.1006/bbrc.1993.1017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Human GRO and rat CINC proteins are members of the pro-inflammatory "chemokine" superfamily of chemotactic cytokines which includes IL-8. We have used Northern and Southern blot analyses to compare the expression of CINC-related and GRO transcripts in human cells and to compare the hybridization patterns of CINC and GRO probes in human and rat genomic DNA. Our data indicate that rat CINC is encoded by a single gene unlike GRO-alpha, -beta and -gamma which are encoded by three distinct genes and that they are the nearest homologs to each other from their respective species.
Collapse
Affiliation(s)
- J Zagorski
- Department of Health Sciences, Monsanto Company, St. Louis, MO 63167
| | | |
Collapse
|
21
|
Abstract
The U14 RNA of Saccharomyces cerevisiae is a small nucleolar RNA (snoRNA) required for normal production of 18S rRNA. Depletion of U14 results in impaired processing of pre-rRNA, deficiency in 18S-containing intermediates and marked under-accumulation of mature 18S RNA. The present report describes results of functional mapping of U14, by a variety of mutagenic approaches. Special attention was directed at assessing the importance of sequence elements conserved between yeast and mouse U14 as well as other snoRNA species. Functionality was assessed in a test strain containing a galactose dependent U14 gene. The results show portions of three U14 conserved regions to be required for U14 accumulation or function. These regions include bases in: (i) the 5'-proximal box C region, (ii) the 3'-distal box D region, and (iii) a 13 base domain complementary to 18S rRNA. Point and multi-base substitution mutations in the snoRNA conserved box C and box D regions prevent U14 accumulation. Mutations in the essential 18S related domain do not effect U14 levels, but do disrupt synthesis of 18S RNA, indicating that this region is required for function. Taken together, the results suggest that the box C and box D regions influence U14 expression or stability and that U14 function might involve direct interaction with 18S RNA.
Collapse
Affiliation(s)
- A Jarmolowski
- Department of Biochemistry, Lederle Graduate Research Center, University of Massachusetts, Amherst 01003
| | | | | | | |
Collapse
|
22
|
Zagorski J, Tollervey D, Fournier MJ. Characterization of an SNR gene locus in Saccharomyces cerevisiae that specifies both dispensible and essential small nuclear RNAs. Mol Cell Biol 1988; 8:3282-90. [PMID: 2850487 PMCID: PMC363561 DOI: 10.1128/mcb.8.8.3282-3290.1988] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
A genetic locus is described that specifies two Saccharomyces cerevisiae small nuclear RNAs (snRNAs). The genes specifying the two snRNAs are separated by only 67 base pairs and are transcribed in the same direction. The product RNAs contain 128 and 190 nucleotides and are designated snR128 and snR190, respectively. These RNAs resemble snRNAs of other eucaryotes in nuclear localization and possession of a 5' trimethylguanosine cap. Neither snRNA is related in sequence to previously described vertebrate or yeast snRNAs. Both RNAs exhibit properties consistent with nucleolar organization and hydrogen bonding to pre-rRNA species, suggesting possible roles in ribosome biogenesis. The snR128 species cosediments with deproteinized 27S pre-rRNA, whereas snR190 is associated with a 20S intermediate. Gene disruption in vitro followed by replacement of the chromosomal alleles reveals that SNR128 is essential, whereas SNR190 is not.
Collapse
Affiliation(s)
- J Zagorski
- Department of Biochemistry, University of Massachusetts, Amherst 01003
| | | | | |
Collapse
|
23
|
Thompson JR, Zagorski J, Woolford JL, Fournier MJ. Sequence and genetic analysis of a dispensible 189 nucleotide snRNA from Saccharomyces cerevisiae. Nucleic Acids Res 1988; 16:5587-601. [PMID: 3290853 PMCID: PMC336786 DOI: 10.1093/nar/16.12.5587] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The structure of a Saccharomyces cerevisiae gene that encodes a small nuclear RNA (snRNA) of 189 nucleotides is described. This gene, designated SNR189, is located 400 base pairs upstream of the CRY1 gene on yeast chromosome III. Gene replacement analysis revealed the SNR189 gene to be dispensable for growth under a variety of culture conditions. The snR189 sequence lacks homology with other sequenced yeast or metazoan snRNAs.
Collapse
Affiliation(s)
- J R Thompson
- Department of Biochemistry, University of Massachusetts, Amherst 01003
| | | | | | | |
Collapse
|
24
|
Abstract
The gene coding for the metabolically stable 6S RNA of Escherichia coli has been cloned, sequenced, and partially characterized in expression analyses. The DNA sequence results confirm the accuracy of the previously established RNA sequence and, with genomic hybridization data, reveal that there is only one copy of the 6S DNA in the chromosome. Consistent with its relaxed mode of expression, the promoter region of the 6S RNA gene was found to lack the hypothetical GC-rich discriminator domain common to other stable RNA genes under stringent control. The sequence results also revealed the occurrence of a 540-base-pair open reading frame immediately downstream from the 6S RNA coding region. Results from the expression analyses show that the protein and RNA coding regions are cotranscribed in vitro and that the open reading frame is translated in vivo.
Collapse
|
25
|
Abstract
The structure of the Escherichia coli gene coding for the metabolically stable 4.5 S RNA has been determined by cloning and DNA sequence analysis. Results from Southern hybridization assays carried out prior to cloning show the 4.5 S DNA to be limited to a single locus in the E. coli K12 genome. A 5.4 X 10(3) base DNA fragment containing the 4.5 S DNA was cloned into plasmid pBR322 for restriction, hybridization and sequence analyses. Cells harboring the cloned gene overproduce the 4.5 S RNA by 15-fold under normal culturing conditions; however, no effect on growth rate is observed. DNA sequencing revealed only one copy of the 4.5 S RNA gene, with a deduced RNA sequence both longer at 114 bases and slightly different from the RNA sequence reported earlier. A promoter structure immediately preceding the structural gene shows good agreement with the prokaryotic consensus sequence at both the -35 and -10 regions. In addition, a G + C-rich sequence between the Pribnow box and the start of transcription agrees well with an apparent consensus sequence found for other stable RNA genes also under stringent control. No clearly recognizable termination signal was found immediately downstream from the 3' terminus of the 4.5 S DNA, although structural elements with that potential appear to occur. A potential coding sequence for a protein occurs about 100 bases downstream from the 4.5 S DNA, suggesting the possibility of a dual function 4.5 S RNA-mRNA transcript.
Collapse
|
26
|
Hsu LM, Klee HJ, Zagorski J, Fournier MJ. Structure of an Escherichia coli tRNA operon containing linked genes for arginine, histidine, leucine, and proline tRNAs. J Bacteriol 1984; 158:934-42. [PMID: 6327651 PMCID: PMC215531 DOI: 10.1128/jb.158.3.934-942.1984] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A plasmid containing a gene for the most abundant Escherichia coli leucine isoacceptor tRNA, tRNALeu1 (anticodon CAG) was isolated from the Clarke-Carbon bank of cloned E. coli DNA. The clone contains a 12.3-kilobase DNA insert which was mapped by F' DNA hybridization analysis to the region 82 to 89 min on the chromosome. The cloned tDNALeu corresponds to the minor of two chromosomal regions containing different amounts of DNA complementary to tRNALeuCAG . Sequencing of the tDNA region revealed it to contain a multimeric transcription unit consisting of four different tRNA genes. The genes are in the arrangement 5'-leader- tRNAArgCCG -57 base pairs- tRNAHisGUG -20 base pairs- tRNALeuCAG -42 base pairs- tRNAProUGG -3'. Coordinate expression of the component tRNAs in vivo and the absence of intercistronic promoters indicated that all four tDNAs reside in the same operon. The tDNA sequence is bounded by a promoter element showing good agreement with the procaryotic consensus sequence and a GC-rich stem-loop element that corresponds to a rho-independent terminator. The promoter region contains a GC-rich sequence that agrees with a suggested consensus stringency control element and two domains possessing dyad symmetry which flank the Pribnow box and include the putative stringency control region.
Collapse
|