51
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Jenkins CCL, Mata J, Crane RF, Thomas B, Akoulitchev A, Bähler J, Norbury CJ. Activation of AP-1-dependent transcription by a truncated translation initiation factor. EUKARYOTIC CELL 2006; 4:1840-50. [PMID: 16278451 PMCID: PMC1287857 DOI: 10.1128/ec.4.11.1840-1850.2005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Int6/eIF3e is a highly conserved subunit of eukaryotic translation initiation factor 3 (eIF3) that has also been reported to interact with subunits of the proteasome and the COP9 signalosome. Overexpression of full-length Int6 or a 13-kDa C-terminal fragment, Int6CT, in the fission yeast Schizosaccharomyces pombe causes multidrug resistance that requires the otherwise inessential AP-1 transcription factor Pap1. Here we show for the first time that Int6CT acts to increase the transcriptional activity of Pap1. Microarray hybridization data indicate that Int6CT overexpression resulted in the up-regulation of 67 genes; this expression profile closely matched that of cells overexpressing Pap1. Analysis of the upstream regulatory sequences of these genes showed that the majority contained AP-1 consensus binding sites. Partial defects in ubiquitin-dependent proteolysis have been suggested to confer Pap1-dependent multidrug resistance, but no such defect was seen on Int6CT overexpression. Indeed, none of the previously identified interactions of endogenous Int6 was required for the activation of Pap1 transcription described here. Moreover, Int6CT-induced activation of Pap1-responsive gene expression was independent of the ability of Pap1 to undergo a redox-regulated conformational change which mediates its relocalization to the nucleus and expression of oxidative stress response genes. Int6CT therefore activates Pap1-dependent transcription by a novel mechanism.
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Affiliation(s)
- Caroline C L Jenkins
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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52
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Maupin-Furlow JA, Humbard MA, Kirkland PA, Li W, Reuter CJ, Wright AJ, Zhou G. Proteasomes from Structure to Function: Perspectives from Archaea. Curr Top Dev Biol 2006; 75:125-69. [PMID: 16984812 DOI: 10.1016/s0070-2153(06)75005-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Insight into the world of proteolysis has expanded considerably over the past decade. Energy-dependent proteases, such as the proteasome, are no longer viewed as nonspecific degradative enzymes associated solely with protein catabolism but are intimately involved in controlling biological processes that span life to death. The proteasome maintains this exquisite control by catalyzing the precisely timed and rapid turnover of key regulatory proteins. Proteasomes also interplay with chaperones to ensure protein quality and to readjust the composition of the proteome following stress. Archaea encode proteasomes that are highly related to those of eukaryotes in basic structure and function. Investigations of archaeal proteasomes coupled with those of eukaryotes has greatly facilitated our understanding of the molecular mechanisms that govern regulated protein degradation by this elaborate nanocompartmentalized machine.
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Affiliation(s)
- Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida Gainesville, Florida 32611, USA
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53
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Takeda K, Yanagida M. Regulation of nuclear proteasome by Rhp6/Ubc2 through ubiquitination and destruction of the sensor and anchor Cut8. Cell 2005; 122:393-405. [PMID: 16096059 DOI: 10.1016/j.cell.2005.05.023] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 04/14/2005] [Accepted: 05/18/2005] [Indexed: 11/21/2022]
Abstract
While proteasome is central to the degradation of cellular ubiquitinated proteins, the control of its nuclear function is barely understood. Here we show that the fission yeast ubiquitin-conjugating Rhp6/Ubc2/Rad6 and ligating enzymes Ubr1 are responsible for nuclear enrichment of proteasome through the function of Cut8, a nuclear envelope protein. Cut8 is an Rhp6 substrate that physically interacts with and tethers proteasome. Nonubiquitinatable K-all-R Cut8 weakly interacts with proteasome and fails to enrich nuclear proteasome. Consistently, the nuclear enrichment of proteasome also fails in rhp6 and ubr1 null mutants. Further, cut8 null and cut8 K-all-R mutants are hypersensitive to DNA damage, probably due to the paucity of nuclear proteasome. Thus, Rhp6 enhances the retention of nuclear proteasome through regulating Cut8. The short-lived nature of Cut8 is crucial for feedback enrichment of the proteasome within the nucleus. This is likely to be a conserved mechanism as we describe a Cut8 homolog in flies.
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Affiliation(s)
- Kojiro Takeda
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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54
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Buttitta F, Martella C, Barassi F, Felicioni L, Salvatore S, Rosini S, D'Antuono T, Chella A, Mucilli F, Sacco R, Mezzetti A, Cuccurullo F, Callahan R, Marchetti A. Int6 expression can predict survival in early-stage non-small cell lung cancer patients. Clin Cancer Res 2005; 11:3198-204. [PMID: 15867213 DOI: 10.1158/1078-0432.ccr-04-2308] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The Int6 gene was originally identified as a common insertion site for the mouse mammary tumor virus in virally induced mouse mammary tumors. Recent studies indicate that Int6 is a multifaceted protein involved in the regulation of protein translation and degradation through binding with three complexes: the eukaryotic translation initiation factor 3, the proteasome regulatory lid, and the constitutive photomorphogenesis 9 signalosome. This study aimed to investigate the prognostic role of Int6 in a large series of stage I non-small cell lung cancers (NSCLC) patients with long-term follow-up. EXPERIMENTAL DESIGN We determined the methylation status of Int6 DNA by methylation-specific PCR and the steady-state levels of Int6 RNA by quantitative real-time reverse transcription-PCR in 101 NSCLCs and matched normal lung tissues. RESULTS In 27% of the tumors, Int6 RNA levels were reduced relative to normal tissue. In 85% of the tumors with reduced Int6 expression, the transcription promoter and first exon were hypermethylated, whereas only 4% of the tumors with elevated Int6 RNA levels were hypermethylated (P <0.000001). Low levels of Int6 RNA were found a significant predictor of overall and disease-free survival (P=0.0004 and P=0.0020, respectively). A multivariate analysis confirmed that low Int6 expression was the only independent factor to predict poor prognosis, for both overall (P=0.0006) and disease-free (P=0.024) survival. CONCLUSIONS Our results suggest that Int6 expression, evaluated by quantitative real-time PCR, may represent a new prognostic factor in patients with stage I NSCLC.
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Affiliation(s)
- Fiamma Buttitta
- Clinical Research Center, Center of Excellence on Aging, University Foundation, Chieti, Italy
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55
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Zhou C, Arslan F, Wee S, Krishnan S, Ivanov AR, Oliva A, Leatherwood J, Wolf DA. PCI proteins eIF3e and eIF3m define distinct translation initiation factor 3 complexes. BMC Biol 2005; 3:14. [PMID: 15904532 PMCID: PMC1173091 DOI: 10.1186/1741-7007-3-14] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Accepted: 05/17/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND PCI/MPN domain protein complexes comprise the 19S proteasome lid, the COP9 signalosome (CSN), and eukaryotic translation initiation factor 3 (eIF3). The eIF3 complex is thought to be composed of essential core subunits required for global protein synthesis and non-essential subunits that may modulate mRNA specificity. Interactions of unclear significance were reported between eIF3 subunits and PCI proteins contained in the CSN. RESULTS Here, we report the unexpected finding that fission yeast has two distinct eIF3 complexes sharing common core subunits, but distinguished by the PCI proteins eIF3e and the novel eIF3m, which was previously annotated as a putative CSN subunit. Whereas neither eIF3e nor eIF3m contribute to the non-essential activities of CSN in cullin-RING ubiquitin ligase control, eif3m, unlike eif3e, is an essential gene required for global cellular protein synthesis and polysome formation. Using a ribonomic approach, this phenotypic distinction was correlated with a different set of mRNAs associated with the eIF3e and eIF3m complexes. Whereas the eIF3m complex appears to associate with the bulk of cellular mRNAs, the eIF3e complex associates with a far more restricted set. The microarray findings were independently corroborated for a random set of 14 mRNAs by RT-PCR analysis. CONCLUSION We propose that the PCI proteins eIF3e and eIF3m define distinct eIF3 complexes that may assist in the translation of different sets of mRNAs.
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Affiliation(s)
- Chunshui Zhou
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts, 02115, USA
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Fatih Arslan
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts, 02115, USA
| | - Susan Wee
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts, 02115, USA
| | | | - Alexander R Ivanov
- Harvard NIEHS Center Proteomics Facility, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Anna Oliva
- Department of Molecular Genetics and Microbiology, State University of New York, Stony Brook, New York, USA
| | - Janet Leatherwood
- Department of Molecular Genetics and Microbiology, State University of New York, Stony Brook, New York, USA
| | - Dieter A Wolf
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts, 02115, USA
- Harvard NIEHS Center Proteomics Facility, Harvard School of Public Health, Boston, Massachusetts, USA
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56
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Chang EC, Schwechheimer C. ZOMES III: the interface between signalling and proteolysis. Meeting on The COP9 Signalosome, Proteasome and eIF3. EMBO Rep 2005; 5:1041-5. [PMID: 15514681 PMCID: PMC1299170 DOI: 10.1038/sj.embor.7400275] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Accepted: 09/14/2004] [Indexed: 11/10/2022] Open
Affiliation(s)
- Eric C. Chang
- Department of Molecular and Cell Biology and the Breast Centre, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas 77030, USA
- Tel: +1 713 798 3519; Fax: +1 713 798 1642;
| | - Claus Schwechheimer
- Department of Developmental Genetics, Centre for Plant Molecular Biology, Auf der Morgenstelle 5, 72076 Tübingen, Germany
- Tel: +49 7071 297 6669; Fax: +49 7071 295 135;
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57
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Morris C, Jalinot P. Silencing of human Int-6 impairs mitosis progression and inhibits cyclin B-Cdk1 activation. Oncogene 2005; 24:1203-11. [PMID: 15558017 DOI: 10.1038/sj.onc.1208268] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Int-6 protein has been originally identified as the product of a mouse gene being a frequent integration site of the mouse mammary tumour virus. Here, we show that reducing Int-6 expression by RNA interference in HeLa cells markedly alters mitosis progression. Defects in spindle formation, chromosome segregation and cytokinesis were observed. These abnormalities of mitosis completion are correlated with an inhibition of cyclin B-Cdk1 kinase activity, due to a prolonged inhibitory phosphorylated state of Cdk1. In line with this observation, the Wee1 tyrosine kinase that negatively controls Cdk1 was less efficiently inactivated during G2 in Int-6-depleted cells. These findings support the notion that the oncogenic properties associated with alteration of Int-6 originate from chromosomal instability.
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Affiliation(s)
- Christelle Morris
- Laboratoire de Biologie Moléculaire de la Cellule, UMR5161-CNRS, IFR 128 Biosciences Lyon-Gerland, ENS de Lyon, 46, Allée d'Italie, 69364 Lyon, France
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58
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Collin P, Beauregard PB, Elagöz A, Rokeach LA. A non-chromosomal factor allows viability of Schizosaccharomyces pombe lacking the essential chaperone calnexin. J Cell Sci 2004; 117:907-18. [PMID: 14963023 DOI: 10.1242/jcs.00943] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Calnexin is a molecular chaperone playing key roles in protein folding and the quality control of this process in the endoplasmic reticulum. We, and others, have previously demonstrated that cnx1(+), the gene encoding the calnexin homologue in Schizosaccharomyces pombe, is essential for viability. We show that a particular cnx1 mutant induces a novel mechanism allowing the survival of S. pombe cells in the absence of calnexin/Cnx1p. Calnexin independence is dominant in diploid cells and is inherited in a non-Mendelian manner. Remarkably, this survival pathway, bypassing the necessity for calnexin, can be transmitted by transformation of cell extracts into a wild-type naive strain, thus implicating a non-chromosomal factor. Nuclease and UV treatments of cells extracts did not obliterate transmission of calnexin independence by transformation. However, protease digestion of extracts did reduce the appearance of calnexin-independent cells, indicating that a protein element is required for calnexin-less viability. We discuss a model in which this calnexin-less survival mechanism would be activated and perpetuated by a protein component acting as a genetic element.
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Affiliation(s)
- Philippe Collin
- Department of Biochemistry, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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59
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Wendler P, Lehmann A, Janek K, Baumgart S, Enenkel C. The Bipartite Nuclear Localization Sequence of Rpn2 Is Required for Nuclear Import of Proteasomal Base Complexes via Karyopherin αβ and Proteasome Functions. J Biol Chem 2004; 279:37751-62. [PMID: 15210724 DOI: 10.1074/jbc.m403551200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
26 S proteasomes fulfill final steps in the ubiquitin-dependent degradation pathway by recognizing and hydrolyzing ubiquitylated proteins. As the 26 S proteasome mainly localizes to the nucleus in yeast, we addressed the question how this 2-MDa multisubunit complex is imported into the nucleus. 26 S proteasomes consist of a 20 S proteolytically active core and 19 S regulatory particles, the latter composed of two subcomplexes, namely the base and lid complexes. We have shown that 20 S core particles are translocated into the nucleus as inactive precursor complexes via the classic karyopherin alphabeta import pathway. Here, we provide evidence that nuclear import of base and lid complexes also depends on karyopherin alphabeta. Potential classic nuclear localization sequences (NLSs) of base subunits were analyzed. Rpn2 and Rpt2, a non-ATPase subunit and an ATPase subunit of the base complex, harbor functional NLSs. The Rpt2 NLS deletion yielded wild type localization. However, the deletion of the Rpn2 NLS resulted in improper nuclear proteasome localization and impaired proteasome function. Our data support the model by which nuclear 26 S proteasomes are assembled from subcomplexes imported by karyopherin alphabeta.
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Affiliation(s)
- Petra Wendler
- Institut für Biochemie CCM, Charité, Universitätsmedizin Berlin, Monbijoustrasse 2, D-10117 Berlin, Germany
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60
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Li Y, Chang EC. Schizosaccharomyces pombe Ras1 effector, Scd1, interacts with Klp5 and Klp6 kinesins to mediate cytokinesis. Genetics 2004; 165:477-88. [PMID: 14573463 PMCID: PMC1462777 DOI: 10.1093/genetics/165.2.477] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fission yeast Scd1 is an exchange factor for Cdc42 and an effector of Ras1. In a screen for scd1 interacting genes, we isolated klp5 and klp6, which encode presumptive kinesins. Klp5 and Klp6 form a complex to control the same processes, which so far include microtubule dynamics and chromosome segregation. We showed that klp5 or klp6 inactivation in combination with the scd1 deletion (scd1delta) created a synthetic temperature-dependent growth defect. Further genetic analysis demonstrated that Klp5 and Klp6 interacted specifically with the Ras1-Scd1 pathway, but not with the Ras1-Byr2 pathway. In addition, Klp5 and Klp6 can stably associate with Scd1 and Cdc42. A deletion in the Scd1 C terminus, which contains the PB1 domain, prevented Scd1 binding to Klp5/6 and caused a growth defect in Klp5/6 mutant cells that is indistinguishable from that induced by scd1delta. Analysis of the double-mutant phenotype indicated that at the nonpermissive temperature, cells failed to undergo cytokinesis efficiently. These cells contained abnormal contractile rings in which F-actin and Mid1, a key regulator of F-actin ring formation and positioning, are mispositioned and fragmented. These data suggest that Klp5/6 cooperate with the Ras1-Scd1 pathway to influence proper formation of the contractile ring for cytokinesis.
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Affiliation(s)
- Yingchun Li
- Baylor College of Medicine, Department of Molecular and Cellular Biology, The Breast Center, Methodist Hospital, Houston, Texas 77030, USA
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61
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Watkins SJ, Norbury CJ. Cell cycle-related variation in subcellular localization of eIF3e/INT6 in human fibroblasts. Cell Prolif 2004; 37:149-60. [PMID: 15030549 PMCID: PMC6495725 DOI: 10.1111/j.1365-2184.2004.00305.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The Int-6 gene is a site of mouse mammary tumour virus (MMTV) integration in murine tumours and INT6 protein has been identified independently as a subunit (eIF3e) of the eukaryotic translation initiation factor eIF3. In addition, the protein can interact with two other multi-subunit complexes: the COP9 signalosome (CSN) and the proteasome. The role of INT6 in tumourigenesis is nonetheless currently unclear. Here, using immunofluorescence microscopy, we show that eIF3e/INT6 is localized in part to the nucleus, while other eIF3 components are cytoplasmic. Primary human fibroblasts, but not their transformed counterparts, showed reduced nuclear INT6 staining in some cells, and this reduction was maximal in early S phase. This variation in eIF3e/INT6 may indicate regulated shuttling between cellular compartments and would be consistent with the presence of a nuclear export signal as well as a nuclear localization signal in the protein sequence. Loss of regulation of eIF3e/INT6 redistribution may therefore be a significant feature of malignancy in human cells.
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Affiliation(s)
- S J Watkins
- University of Oxford, Sir William Dunn School of Pathology, Oxford, UK
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62
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Oshima Y, Ueda M, Yamashita Y, Choi YL, Ota J, Ueno S, Ohki R, Koinuma K, Wada T, Ozawa K, Fujimura A, Mano H. DNA microarray analysis of hematopoietic stem cell-like fractions from individuals with the M2 subtype of acute myeloid leukemia. Leukemia 2003; 17:1990-7. [PMID: 14513049 DOI: 10.1038/sj.leu.2403098] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acute myeloid leukemia (AML) may develop de novo or secondarily to myelodysplastic syndrome (MDS). Although the clinical outcome of MDS-related AML is worse than that of de novo AML, it is not easy to differentiate between these two clinical courses without a record of prior MDS. Large-scale profiling of gene expression by DNA microarray analysis is a promising approach with which to identify molecular markers specific to de novo or MDS-related AML. This approach has now been adopted with AC133-positive hematopoietic stem cell-like fractions purified from 10 individuals, each with either de novo or MDS-related AML of the M2 subtype. Sets of genes whose activity was associated with either disease course were identified. Furthermore, on the basis of the expression profiles of these genes, it was possible to predict correctly the clinical diagnosis for 17 (85%) of the 20 cases in a cross-validation trial. Similarly, different sets of genes were identified whose expression level was associated with clinical outcome after induction chemotherapy. These data suggest that, at least in terms of gene expression profiles, de novo AML and MDS-related AML are distinct clinical entities.
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MESH Headings
- Antigens, CD/genetics
- Antigens, CD34/genetics
- Base Sequence
- Blast Crisis/genetics
- Bone Marrow Cells/pathology
- DNA Primers
- Hematopoietic Stem Cells/classification
- Hematopoietic Stem Cells/pathology
- Humans
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/pathology
- Microscopy, Fluorescence
- Oligonucleotide Array Sequence Analysis
- Predictive Value of Tests
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription, Genetic
- Treatment Failure
- Treatment Outcome
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Affiliation(s)
- Y Oshima
- Division of Clinical Pharmacology, Jichi Medical School, Yakushiji, Kawachigun, Tochigi, Japan
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63
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Yen HCS, Espiritu C, Chang EC. Rpn5 is a conserved proteasome subunit and required for proper proteasome localization and assembly. J Biol Chem 2003; 278:30669-76. [PMID: 12783882 DOI: 10.1074/jbc.m302093200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proper function of the 26 S proteasome requires assembly of the regulatory complex, which is composed of the lid and base subcomplexes. We characterized Rpn5, a lid subunit, in fission yeast. We show that Rpn5 associates with the proteasome rpn5. Deletion (rpn5Delta) exacerbates the growth defects in proteasome mutants, leading to mitotic abnormalities, which correlate with accumulation of polyubiquitinated proteins, such as Cut2/securin. Rpn5 expression is tightly controlled; both overexpression and deletion of rpn5 impair proteasome functions. The proteasome is assembled around the inner nuclear membrane in wild-type cells; however, in rpn5Delta cells, proteasome subunits are improperly assembled and/or localized. In the lid mutants, Rpn5 is mislocalized in the cytosol, while in the base mutants, Rpn5 can enter the nucleus, but is left in the nucleoplasm, and not assembled into the nuclear membrane. These results suggest that Rpn5 is a dosage-dependent proteasome regulator and plays a role in mediating proper proteasome assembly. Moreover, the Rpn5 assembly may be a cooperative process that involves at least two steps: 1) nuclear import and 2) subsequent assembly into the nuclear membrane. The former step requires other components of the lid, while the latter requires the base. Human Rpn5 rescues the phenotypes associated with rpn5Delta and is incorporated into the yeast proteasome, suggesting that Rpn5 functions are highly conserved.
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Affiliation(s)
- Hsueh-Chi S Yen
- Department of Molecular and Cellular Biology, The Breast Center, Baylor College of Medicine, Methodist Hospital, Houston, Texas 77030, USA
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64
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Current awareness on yeast. Yeast 2003. [DOI: 10.1002/yea.947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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65
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Abstract
Similarities between the three related "PCI" complexes--eIF3, the COP9 signalosome and the proteasome lid--have hinted at novel pathways controlling protein homeostasis. Recent experiments with fission yeast have begun to weigh in with genetic evidence.
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