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Role of the Heme Activator Protein Complex in the Sexual Development of Cryptococcus neoformans. mSphere 2022; 7:e0017022. [PMID: 35638350 PMCID: PMC9241503 DOI: 10.1128/msphere.00170-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The CCAAT-binding heme activator protein (HAP) complex, comprising the DNA-binding heterotrimeric complex Hap2/3/5 and transcriptional activation subunit HapX, is a key regulator of iron homeostasis, mitochondrial functions, and pathogenicity in Cryptococcus neoformans, which causes fatal meningoencephalitis. However, its role in the development of human fungal pathogens remains unclear. To elucidate the role of the HAP complex in C. neoformans development, we constructed hap2Δ, hap3Δ, hap5Δ, and hapXΔ mutants and their complemented congenic MATα H99 and MATa YL99a strains. The HAP complex plays a conserved role in iron utilization and stress responses in cells of both mating types. Deletion of any of the HAP complex components markedly enhances filamentation during bisexual mating. However, the Hap2/3/5 complex, but not HapX, is crucial in repressing pheromone production and cell fusion and is thus a critical repressor of sexual differentiation of C. neoformans. Interestingly, deletion of the heterotrimeric complex transcriptionally regulated both positive and negative regulators in the pheromone-responsive Cpk1 mitogen-activated protein kinase (MAPK) pathway. Chromatin immunoprecipitation-quantitative PCR analysis revealed that the HAP complex physically bound to the CCAAT motif of the CRG1 and GPA2 promoter regions. Notably, the HAP complex was differentially localized depending on the mating type in basal conditions; it was enriched in the nuclei of MATα cells but diffused in the cytoplasm of MATa cells. Interestingly, however, a portion of the HAP complex in both mating types relocalized to the cell membrane during mating. In conclusion, the Hap2/3/5 heterotrimeric complex and HapX play major and minor roles, respectively, in repressing the sexual development of C. neoformans in association with the Cpk1 MAPK pathway. IMPORTANCECryptococcus neoformans isolates are of two mating types: MATα strains, which are predominant, and MATa strains, isolated from the sub-Saharan African region, where cryptococcosis is most abundant and severe. Here, we demonstrated the function of the CCAAT-binding HAP complex (Hap2/3/5/X) as a transcriptional repressor of Cpk1 pathway-related genes in cells of both mating types. Deletion of any HAP complex component markedly enhanced filamentation without affecting normal sporulation. In particular, deletion of the DNA-binding HAP complex components (Hap2/3/5), but not HapX, markedly enhanced pheromone production and cell fusion efficiency, validating its repressive role in the early stage of mating in C. neoformans. The HAP complex regulates the expression of both negative and positive mating regulators and is thus crucial for the regulation of the Cpk1 MAPK pathway during mating. This study provides insights into the complex signaling networks governing the sexual differentiation of C. neoformans.
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Ronzio M, Bernardini A, Pavesi G, Mantovani R, Dolfini D. On the NF-Y regulome as in ENCODE (2019). PLoS Comput Biol 2020; 16:e1008488. [PMID: 33370256 PMCID: PMC7793273 DOI: 10.1371/journal.pcbi.1008488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 01/08/2021] [Accepted: 11/04/2020] [Indexed: 11/19/2022] Open
Abstract
NF-Y is a trimeric Transcription Factor -TF- which binds with high selectivity to the conserved CCAAT element. Individual ChIP-seq analysis as well as ENCODE have progressively identified locations shared by other TFs. Here, we have analyzed data introduced by ENCODE over the last five years in K562, HeLa-S3 and GM12878, including several chromatin features, as well RNA-seq profiling of HeLa cells after NF-Y inactivation. We double the number of sequence-specific TFs and co-factors reported. We catalogue them in 4 classes based on co-association criteria, infer target genes categorizations, identify positional bias of binding sites and gene expression changes. Larger and novel co-associations emerge, specifically concerning subunits of repressive complexes as well as RNA-binding proteins. On the one hand, these data better define NF-Y association with single members of major classes of TFs, on the other, they suggest that it might have a wider role in the control of mRNA production. The ongoing ENCODE consortium represents a useful compendium of locations of TFs, chromatin marks, gene expression data. In previous reports, we identified modules of CCAAT-binding NF-Y with individual TFs. Here, we analyzed all 363 factors currently present: 68 with enrichment of CCAAT in their locations, 38 with overlap of peaks. New sequence-specific TFs, co-activators and co-repressors are reported. Co-association patterns correspond to specific targeted genes categorizations and gene expression changes, as assessed by RNA-seq after NF-Y inactivation. These data widen and better define a coherent model of synergy of NF-Y with selected groups of TFs and co-factors.
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Affiliation(s)
- Mirko Ronzio
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Andrea Bernardini
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Giulio Pavesi
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Roberto Mantovani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Diletta Dolfini
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
- * E-mail:
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Mao Y, Chen C. The Hap Complex in Yeasts: Structure, Assembly Mode, and Gene Regulation. Front Microbiol 2019; 10:1645. [PMID: 31379791 PMCID: PMC6652802 DOI: 10.3389/fmicb.2019.01645] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/03/2019] [Indexed: 01/19/2023] Open
Abstract
The CCAAT box-harboring proteins represent a family of heterotrimeric transcription factors which is highly conserved in eukaryotes. In fungi, one of the particularly important homologs of this family is the Hap complex that separates the DNA-binding domain from the activation domain and imposes essential impacts on regulation of a wide range of cellular functions. So far, a comprehensive summary of this complex has been described in filamentous fungi but not in the yeast. In this review, we summarize a number of studies related to the structure and assembly mode of the Hap complex in a list of representative yeasts. Furthermore, we emphasize recent advances in understanding the regulatory functions of this complex, with a special focus on its role in regulating respiration, production of reactive oxygen species (ROS) and iron homeostasis.
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Affiliation(s)
- Yinhe Mao
- Key Laboratory of Molecular Virology and Immunology, Unit of Pathogenic Fungal Infection and Host Immunity, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Changbin Chen
- Key Laboratory of Molecular Virology and Immunology, Unit of Pathogenic Fungal Infection and Host Immunity, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
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Chen Y, Gao J, Xie J, Liang J, Zheng G, Xie L, Zhang R. Transcriptional regulation of the matrix protein Shematrin-2 during shell formation in pearl oyster. J Biol Chem 2018; 293:17803-17816. [PMID: 30282805 DOI: 10.1074/jbc.ra118.005281] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/21/2018] [Indexed: 01/17/2023] Open
Abstract
The molluscan shell is a fascinating biomineral consisting of a highly organized calcium carbonate composite. Biomineralization is elaborately controlled and involves several macromolecules, especially matrix proteins, but little is known about the regulatory mechanisms. The matrix protein Shematrin-2, expression of which peaks in the mantle tissues and in the shell components of the pearl oyster Pinctada fucata, has been suggested to be a key participant in biomineralization. Here, we expressed and purified Shematrin-2 from P. fucata and explored its function and transcriptional regulation. An in vitro functional assay revealed that Shematrin-2 binds the calcite, aragonite, and chitin components of the shell, decreases the rate of calcium carbonate deposition, and changes the morphology of the deposited crystal in the calcite crystallization system. Furthermore, we cloned the Shematrin-2 gene promoter, and analysis of its sequence revealed putative binding sites for the transcription factors CCAAT enhancer-binding proteins (Pf-C/EBPs) and nuclear factor-Y (NF-Y). Using transient co-transfection and reporter gene assays, we found that cloned and recombinantly expressed Pf-C/EBP-A and Pf-C/EBP-B greatly and dose-dependently up-regulate the promoter activity of the Shematrin-2 gene. Importantly, Pf-C/EBP-A and Pf-C/EBP-B knockdowns decreased Shematrin-2 gene expression and induced changes in the inner-surface structures in prismatic layers that were similar to those of antibody-based Shematrin-2 inhibition. Altogether, our data reveal that the transcription factors Pf-C/EBP-A and Pf-C/EBP-B up-regulate the expression of the matrix protein Shematrin-2 during shell formation in P. fucata, improving our understanding of the transcriptional regulation of molluscan shell development at the molecular level.
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Affiliation(s)
- Yan Chen
- From the Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084
| | - Jing Gao
- From the Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084
| | - Jun Xie
- From the Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084
| | - Jian Liang
- From the Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084
| | - Guilan Zheng
- From the Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084
| | - Liping Xie
- From the Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084.
| | - Rongqing Zhang
- From the Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing 100084; Department of Biotechnology and Biomedicine, Yangtze Delta Region Institute of Tsinghua University, Jiaxing 314006, Zhejiang Province, China.
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5
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Luan X, Ito Y, Zhang Y, Diekwisch TGH. Characterization of the mouse CP27 promoter and NF-Y mediated gene regulation. Gene 2010; 460:8-19. [PMID: 20388536 DOI: 10.1016/j.gene.2010.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 03/26/2010] [Accepted: 03/27/2010] [Indexed: 01/02/2023]
Abstract
The cp27 gene is a highly conserved and unique gene with important roles related to craniofacial organogenesis. The present study is a first analysis of the CP27 promoter and its regulation. Here, we have cloned the promoter of the mouse cp27 gene, examined its transcriptional activity, and identified transcription factor binding sites in the proximal promoter region. Two major transcription start sites were mapped adjacent to exon 1. Promoter function analysis of the 5' flanking region by progressive 5' deletion mutations localized transcription repression elements between -1993bp and -969bp and several positive elements between -968bp and the preferred transcription start site. EMSA and functional studies indicated two function-cooperative CCAAT boxes and identified the NF-Y transcription factor as the CCAAT activator controlling transactivation of the CP27 promoter. In addition, this study demonstrated that for its effective binding and function, NF-Y required not only the minimal DNA segment length identified by deletion studies, but also a defined nucleotide sequence in the distal 3' flanking region of the CP27 proximal promoter CCAAT box. These results provide a basis for our understanding of the specific regulation of the cp27 gene in the NF-Y-mediated gene transcription network.
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Affiliation(s)
- Xianghong Luan
- Brodie Laboratory for Craniofacial Genetics, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL 60612, USA
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6
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Garand M, Bastajian N, Nesheim ME, Boffa MB, Koschinsky ML. Molecular analysis of the human thrombin-activatable fibrinolysis inhibitor gene promoter. Br J Haematol 2007; 138:231-44. [PMID: 17593031 DOI: 10.1111/j.1365-2141.2007.06640.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Thrombin-activatable fibrinolysis inhibitor (TAFI) is a carboxypeptidase B-like pro-enzyme that, once activated, attenuates fibrinolysis. Little is presently known of the factors that regulate expression of CPB2, the gene encoding TAFI. This study identified 10 potential transcription factor binding sites (denoted A-J) within the proximal promoter region of CPB2, spanning nucleotides -425 to +21; two of these represent previously-described binding sites for CCAAT/enhancer binding protein and glucocorticoid receptor. We identified additional transcription factors that bind within the proximal CPB2 promoter, namely, nuclear factor-Y (NF-Y) and hepatocyte nuclear factor-1alpha (HNF-1alpha). Binding of NF-Y to the region between nucleotides -76 to -59 (Site B) is important for basal CPB2 promoter activity; NF-Y may be a key factor for the recruitment of the transcriptional machinery to the TAFI gene promoter. HNF-1alpha binds at the interface between Sites C and B. Transient transfections of CPB2 promoter-reporter constructs showed that HNF-1alpha binding is essential for the activity of this promoter in HepG2 cells, indicating that HNF-1alpha is involved in the liver-specific expression of CPB2.
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Affiliation(s)
- Mathieu Garand
- Department of Biochemistry, Queen's University, Kingston, ON, Canada
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7
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Xu Y, Zhou YL, Luo W, Zhu QS, Levy D, MacDougald OA, Snead ML. NF-Y and CCAAT/enhancer-binding protein alpha synergistically activate the mouse amelogenin gene. J Biol Chem 2006; 281:16090-8. [PMID: 16595692 DOI: 10.1074/jbc.m510514200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Amelogenin is the major protein component of the forming enamel matrix. In situ hybridization revealed a periodicity for amelogenin mRNA hybridization signals ranging from low to high transcript abundance on serial sections of developing mouse teeth. This in vivo observation led us to examine the amelogenin promoter for the activity of transcription factor(s) that account for this expression aspect of the regulation for the amelogenin gene. We have previously shown that CCAAT/enhancer-binding protein alpha (C/EBPalpha) is a potent transactivator of the mouse X-chromosomal amelogenin gene acting at the C/EBPalpha cis-element located in the -70/+52 minimal promoter. The minimal promoter contains a reversed CCAAT box (-58/-54) that is four base pairs downstream from the C/EBPalpha binding site. Similar to the C/EBPalpha binding site, the integrity of the reversed CCAAT box is also required for maintaining the activity of the basal promoter. We therefore focused on transcription factors that interact with the reversed CCAAT box. Using electrophoretic mobility shift assays we demonstrated that NF-Y was directly bound to this reversed CCAAT site. Co-transfection of C/EBPalpha and NF-Y synergistically increased the promoter activity. In contrast, increased expression of NF-Y alone had only marginal effects on the promoter. A dominant-negative DNA binding-deficient NF-Y mutant (NF-YAm29) dramatically decreased the promoter activity both in the absence or presence of exogenous expression of C/EBPalpha. We identified protein-protein interactions between C/EBPalpha and NF-Y by a co-immunoprecipitation analysis. These results suggest that C/EBPalpha and NF-Y synergistically activate the mouse amelogenin gene and can contribute to its physiological regulation during amelogenesis.
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Affiliation(s)
- Yucheng Xu
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California 90033, USA
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8
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Brecht K, Simonen M, Kamke M, Heim J. Hematopoietic transcription factor GATA-2 promotes upregulation of alpha globin and cell death in FL5.12 cells. Apoptosis 2006; 10:1063-78. [PMID: 16151640 DOI: 10.1007/s10495-005-0623-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently we showed that alpha globin is a novel pro-apoptotic factor in programmed cell death in the pro-B cell line, FL5.12. Alpha globin was also upregulated in various other cell lines after different apoptotic stimuli. Under withdrawal of IL-3, overexpression of alpha globin accelerated apoptosis in FL5.12. Here, we have studied how transcription of alpha globin is placed in the broader context of apoptosis. We used Affymetrix chip technology and RT QPCR to compare expression patterns of FL5.12 cells growing with or without IL-3 to search for transcription factors which were concomitantly upregulated with alpha globin. The erythroid-specific transcription factor GATA-2 was the earliest and most prominently upregulated candidate. GATA-1 was expressed at low levels and was weakly induced while GATA-3 was completely absent. To evaluate the influence of GATA-2 on alpha globin expression and cell viability we overexpressed GATA-2 in FL5.12 cells. Interestingly, high expression of GATA-2 resulted in cell death and elevated alpha globin levels in FL5.12 cells. Transduction of antisense GATA-2 prevented both increase of GATA-2 and alpha globin under apoptotic conditions and delayed cell death. We suggest a role of GATA-2 in apoptosis besides its function in maintenance and proliferation of immature hematopoietic progenitors.
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Affiliation(s)
- K Brecht
- Novartis Institutes for BioMedical Research Basel, CH-4002 Basel, Switzerland.
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9
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DePamphili ML. How transcription factors regulate origins of DNA replication in eukaryotic cells. Trends Cell Biol 2004; 3:161-7. [PMID: 14731611 DOI: 10.1016/0962-8924(93)90137-p] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Eukaryotic chromosomes contain a few thousand origins of DNA replication, which are activated in a temporal and spatial order during S phase. One parameter that is strongly implicated in determining the order of replication is transcription. This review focuses on the role of transcription factors in activating origins of replication in eukaryotic cells. Studies of viral and mitochondrial replication origins have revealed several mechanisms by which transcription factors activate origins, but it remains to be seen whether any of these are used to regulate cellular chromosome replication.
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Affiliation(s)
- M L DePamphili
- Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110, USA
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10
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Rafty LA, Santiago FS, Khachigian LM. NF1/X represses PDGF A-chain transcription by interacting with Sp1 and antagonizing Sp1 occupancy of the promoter. EMBO J 2002; 21:334-43. [PMID: 11823426 PMCID: PMC125828 DOI: 10.1093/emboj/21.3.334] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The regulatory mechanisms mediating basal and inducible platelet-derived growth factor (PDGF)-A expression have been the focus of intense recent investigation, but repression of PDGF-A expression is largely unexplored. Here we isolated a nuclear factor that interacts with the proximal region of the PDGF-A promoter using bulk binding assays and chromatography techniques. Peptide mass fingerprint and supershift analysis revealed this DNA-binding protein to be NF1/X. NF1/X repressed PDGF-A promoter-dependent transcription and endogenous mRNA expression, which was reversible by oligonucleotide decoys bearing an NF1/X-binding site. Mutation in the DNA-binding domain of NF1/X abolished its repression of PDGF-A promoter. NF1/X antagonized the activity of a known activator of the PDGF-A chain, Sp1, by inhibiting its occupancy of the proximal PDGF-A promoter. NF1/X physically and specifically interacts with Sp1 via its subtype-specific domain and blocks Sp1 induction of the promoter. NF1/X residues 311-416 mediated NF1/X suppression of basal PDGF-A transcription, whereas residues 243-416 were required for NF1/X repression of Sp1-inducible promoter activity. These findings demonstrate that repression of PDGF-A gene transcription is governed by interplay between NF1/X and Sp1.
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Affiliation(s)
| | | | - Levon M. Khachigian
- Centre for Thrombosis and Vascular Research, Department of Pathology, The University of New South Wales and Department of Haematology, Prince of Wales Hospital, Sydney, Australia
Corresponding author e-mail:
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11
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Iwano S, Saito T, Takahashi Y, Fujita K, Kamataki T. Cooperative regulation of CYP3A5 gene transcription by NF-Y and Sp family members. Biochem Biophys Res Commun 2001; 286:55-60. [PMID: 11485307 DOI: 10.1006/bbrc.2001.5352] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to clarify the mechanism(s) responsible for the transcriptional regulation of the human CYP3A5 gene. It was found that a region from nucleotides -90 to -40 was involved in the transcriptional activity of the CYP3A5 gene by transfection of a series of 5'-truncated promoter-luciferase chimeric genes into human hepatoma HepG2 cells. A gel shift assay using nuclear extracts prepared from HepG2 cells showed that nuclear factor-Y (NF-Y) and specificity protein (Sp) 1 and Sp3 bound to CCAAT box (-78/-68) and a basic transcription element (BTE) (-67/-46) in the CYP3A5 gene. Furthermore, introduction of mutations in the CCAAT box, the BTE, or both elements decreased the transcriptional activity to 10, 21, or 4% of that seen with the intact gene. Thus, we conclude that the transcription of the CYP3A5 gene is cooperatively regulated by NF-Y, Sp1, and Sp3 in HepG2 cells.
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Affiliation(s)
- S Iwano
- Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences, Hokkaido University, N12W6, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
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12
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Zhu K, Henning D, Valdez B, Busch H. Human RNA helicase II/Gu gene: genomic organization and promoter analysis. Biochem Biophys Res Commun 2001; 281:1006-11. [PMID: 11237763 DOI: 10.1006/bbrc.2001.4446] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human RNA helicase II/Gu (hRH II/Gu) protein unwinds double-stranded RNA, folds single-stranded RNA, and may play important roles in ribosomal RNA biogenesis, RNA editing, RNA transport, and general transcription. The genomic organization and the regulation of expression of the hRH II/Gu gene were analyzed. The hRH II/Gu gene is over 29 kb in length, and includes 15 exons. All intron-exon junctions contain consensus GT-AG sequences. An 85 bp basic promoter was identified which lacks a functional TATA box. In LNCaP cells, the hRH II/Gu promoter was up to 50 times as active as pGL2-control vector which has an SV 40 early promoter. Mutation of a putative c-Myc/USF binding site in the region between -110 and -85 caused a decrease in the promoter activity by 2- to 3-fold. A negative regulatory region was also found between -324 and -264. Studies of transcriptional regulation of hRH II/Gu under different physiological and pathophysiological conditions may provide clues to its biological function.
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Affiliation(s)
- K Zhu
- Department of Pharmacology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
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13
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Abstract
Protein coding genes are transcribed by Polymerase II, under the control of short discrete DNA elements in promoters and enhancers, recognized with high efficiency and specificity by trans-acting factors and by general transcription proteins (Tjian and Maniatis, 1994). The former regulate specific genes or set of genes, usually in a tissue-, developmental-, cell-cycle or stimuli-dependent way; the latter are involved in the activation of all promoters, as a whole multi-subunit holoenzyme (Parvis and Young, 1998). A limited set of elements, such as the GC and CCAAT-boxes, are present in a very high number of promoters. The whole process is further complicated by the need to operate in the context of higher order chromatin structures (Workman and Kingston, 1998). This review focuses on the CCAAT sequence and on the NF-Y protein, also known as CBF, which binds to it.
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Affiliation(s)
- R Mantovani
- Dipartimento di Genetica e Biologia dei Microrganismi, Università di Milano, Italy.
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14
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Farina A, Manni I, Fontemaggi G, Tiainen M, Cenciarelli C, Bellorini M, Mantovani R, Sacchi A, Piaggio G. Down-regulation of cyclin B1 gene transcription in terminally differentiated skeletal muscle cells is associated with loss of functional CCAAT-binding NF-Y complex. Oncogene 1999; 18:2818-27. [PMID: 10362252 DOI: 10.1038/sj.onc.1202472] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The observation that cyclin B1 protein and mRNAs are down-regulated in terminally differentiated (TD) C2C12 cells, suggested us to investigate the transcriptional regulation of the cyclin B1 gene in these cells. Transfections of cyclin B1 promoter constructs indicate that two CCAAT boxes support cyclin B1 promoter activity in proliferating cells. EMSAs demonstrate that both CCAAT boxes are recognized by the trimeric NF-Y complex in proliferating but not in TD cells. Transfecting a dominant-negative mutant of NF-YA we provide evidence that NF-Y is required for maximal promoter activity. Addition of recombinant NF-YA to TD C2C12 nuclear extracts restores binding activity in vitro, thus indicating that the loss of NF-YA in TD cells is responsible for the lack of the NF-Y binding to the CCAAT boxes. Consistent with this, we found that the NF-YA protein is absent in TD C2C12 cells. In conclusion, our data demonstrate that NF-Y is required for cyclin B1 promoter activity. We also demonstrate that cyclin B1 expression is regulated at the transcriptional level in TD C2C12 cells and that the switch-off of cyclin B1 promoter activity in differentiated cells depends upon the loss of a functional NF-Y complex. In particular the loss of NF-YA protein is most likely responsible for its inactivation.
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Affiliation(s)
- A Farina
- Laboratorio di Oncogenesi Molecolare, CRS-IRE, Rome, Italy
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15
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Bellorini M, Zemzoumi K, Farina A, Berthelsen J, Piaggio G, Mantovani R. Cloning and expression of human NF-YC. Gene X 1997; 193:119-25. [PMID: 9249075 DOI: 10.1016/s0378-1119(97)00109-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The CCAAT box is an important element in eukaryotic promoters and NF-Y (CBF) is a conserved heterotrimeric protein binding to it. Two subunits, NF-YB and NF-YC, contain a histone-like motif. We cloned the complete cDNA coding for the human NF-YC gene. The ORF codes for a 335 aa protein that shows virtual identity to the rat sequence, confirming the stunning invariance of NF-Y genes across species. We expressed and purified the yeast homology domain of NF-YC in bacteria and performed EMSA together with the corresponding conserved domains of NF-YA and NF-YB, obtaining a CCAAT-binding mini-NF-Y. We evaluated the expression of NF-YC and found that mRNA levels are similar in different human tissues except in testis.
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Affiliation(s)
- M Bellorini
- Dipartimento di Genetica e Biologia dei Microrganismi, Università di Milano, Milan, Italy
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16
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Ueda A, Yoshimura T. Characterization of cis-acting elements of the gene for macrophage-stimulating protein from the human. The involvement of positive and negative regulatory elements. J Biol Chem 1996; 271:20265-72. [PMID: 8702759 DOI: 10.1074/jbc.271.34.20265] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
To analyze the promotor region of the human macrophage-stimulating protein (MSP) gene, the 5'-flanking region of this gene was cloned. The major initiation site was determined at T located 49 base pairs upstream of the translation initiation site by primer extention with mRNA from HepG2 and Hep3B cells. There was no TATA sequence in this region. Transient transfection assay with 5'-deletion constructs showed that the transcription of this gene was regulated by positive and negative regulatory elements (PRE and NRE). The PRE (-34 to +2) was essential for the maximal transcription of this gene, and the NRE (-141 to -34) appeared to be responsible for the tissue-specific expression of the gene. The PRE contained the CCAAT sequence and a mutation from CCAAT to CTGAT resulted in a significant loss of the transcriptional activity. Electrophoretic mobility shift assay suggested that two different proteins bound to the PRE (MSP-PRE-binding protein-1 (MSP-PREB1) and 2). MSP-PREB1 and 2 were detected in various cell types, and the CCAAT sequence was involved in these bindings. These findings indicate that MSP-PREB1 and 2 are positive regulators. Further characterization also revealed that MSP-PREB2 was identical to CCAAT binding transcription factor, also known as NF-Y.
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Affiliation(s)
- A Ueda
- Immunopathology Section, Laboratory of Immunobiology, National Cancer Institute-Frederick Cancer Research and Development Center, Frederick, Maryland 21702, USA
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Puzianowska-Kuznicka M, Shi YB. Nuclear factor I as a potential regulator during postembryonic organ development. J Biol Chem 1996; 271:6273-82. [PMID: 8626421 DOI: 10.1074/jbc.271.11.6273] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Nuclear factor I (NFI) family members are transcription factors that are believed to also participate in DNA replication. We have cloned two Xenopus laevis NFIs that are up-regulated by thyroid hormone. They are 84-95% identical to their counterparts in birds and mammals. In contrast, the two Xenopus NFIs are much less homologous to each other, sharing only 58% homology, which largely resides in the DNA binding domain at the amino terminus. However, both NFIs can bind to a consensus NFI binding site and activate the transcription of a promoter bearing the site. Northern blot reveals that both NFI genes are regulated in tissue- and developmental stage-dependent manners. They are first activated, independently of thyroid hormone, to low levels at stages 23/24, around the onset of larval organogenesis. After stage 54, their mRNA levels are dramatically upregulated by endogenous thyroid hormone, and high levels of their expression correlate with organ-specific metamorphosis. Furthermore, gel mobility shift assay indicates that the NFI proteins are present in different organs and that their levels are regulated similarly to the mRNA levels. These results strongly suggest that NFIs play important roles during postembryonic organ development, in contrast to the general belief that NFIs are ubiquitous factors.
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Affiliation(s)
- M Puzianowska-Kuznicka
- Laboratory of Molecular Embryology, NICHD, National Institutes of Health, Bethesda, Maryland 20892-5430, USA
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18
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Rein T, Förster R, Krause A, Winnacker EL, Zorbas H. Organization of the alpha-globin promoter and possible role of nuclear factor I in an alpha-globin-inducible and a noninducible cell line. J Biol Chem 1995; 270:19643-50. [PMID: 7642653 DOI: 10.1074/jbc.270.33.19643] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Nuclear factor I (NFI) was suggested to be involved in the expression of the human alpha-globin gene. Two established cell lines, which express alpha-globin differentially, were therefore compared for differences in binding of NFI at the alpha-globin promoter in vivo. HeLa cells, in which alpha-globin is repressed, show a high density promoter occupation with several proteins associated with structurally distorted DNA. Cell line K562, which is inducible for alpha-globin, surprisingly was found to be heterogeneous consisting mainly of cells (approximately 95%) unable to express alpha-globin. However, the promoter of the nonexpressing K562 cells was clearly different from that of HeLa cells, being occupied only at basal transcriptional elements. Therefore, the alpha-globin gene in these K562 cells may not be truly repressed, but in an intermediate state between repression and active transcription. The NFI site of the alpha-globin promoter appeared occupied in HeLa but free of proteins in K562 cells. All cells of both cell lines produce NFI, but the composition and DNA binding affinity of NFI species differ significantly between the two cell lines. Therefore, distinct forms of NFI may repress alpha-globin transcription in HeLa cells. However, NFI is apparently not involved in establishing the latent transcriptional state of the majority of K562 cells.
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Affiliation(s)
- T Rein
- Institut für Biochemie, Ludwig-Maximilans-Universität München, Germany
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Affiliation(s)
- P C Van der Vliet
- Laboratory for Physiological Chemistry, University of Utrecht, The Netherlands
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20
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Modulation by vitamin B6 of glucocorticoid receptor-mediated gene expression requires transcription factors in addition to the glucocorticoid receptor. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)36867-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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21
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Apt D, Chong T, Liu Y, Bernard HU. Nuclear factor I and epithelial cell-specific transcription of human papillomavirus type 16. J Virol 1993; 67:4455-63. [PMID: 8392590 PMCID: PMC237828 DOI: 10.1128/jvi.67.8.4455-4463.1993] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The transcription of human papillomavirus type 16 (HPV-16) is mediated by the viral enhancer. Epithelial cell-specific activation is achieved by the cooperative interaction of apparently ubiquitous transcriptional factors. One of them, nuclear factor I (NFI), binds seven sites within the HPV-16 enhancer. Point mutations on enhancer fragments, which retain epithelial cell specificity, verify the functional contribution of NFI. In band shift experiments, the epithelial cell-derived NFI proteins CTF-1, CTF-2, and CTF-3 form a characteristic pattern of heterodimeric complexes which are observed in all epithelial cells tested. Divergence from this pattern in fibroblasts, liver cells, and lymphoid cells correlates with the lack of HPV-16 enhancer activation. The HPV-16 enhancer can be activated by CTF-1 in SL-2 cells, which lack NFI-like proteins. However, exogenous CTF-1 fails to overcome the inactivity of the viral enhancer in fibroblasts. Western immunoblot and supershift analysis shows that exogenously introduced CTF-1 proteins form different heterodimer complexes with the given subset of endogenous NFI proteins in epithelial or fibroblast cells. Polymerase chain reaction analysis and cDNA library screens identified the endogenous fibroblast type NFI as NFI-X, an NFI family member originally cloned from hamster liver cells. The strict correlation between the activation or lack of activation of the HPV-16 enhancer and cell-specific subsets of NFI proteins argues for the pivotal role of NFI binding sites in the epithelial cell-specific function of the viral enhancer.
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Affiliation(s)
- D Apt
- Papillomavirus Biology Laboratory, National University of Singapore, Kent Ridge
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Abstract
This past year has seen a significant increase in our understanding of eukaryotic origins of replication, of the proteins that identify these origins, of DNA sequences that promote their unwinding, and of transcription factors that stimulate origin activity. DNA replication begins at specific sites in both simple and complex genomes, but origins in complex genomes may include nuclear structure as well as DNA sequence.
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Affiliation(s)
- M L DePamphilis
- Roche Institute of Molecular Biology, Nutley, New Jersey 07110-1199
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