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Duan S, Guan S, Fei R, Sun T, Kang X, Xin R, Song W, Sun X. Unraveling the role of PlARF2 in regulating deed formancy in Paeonia lactiflora. PLANTA 2024; 259:133. [PMID: 38668881 DOI: 10.1007/s00425-024-04411-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 04/10/2024] [Indexed: 05/01/2024]
Abstract
MAIN CONCLUSION PlARF2 can positively regulate the seed dormancy in Paeonia lactiflora Pall. and bind the RY cis-element. Auxin, a significant phytohormone influencing seed dormancy, has been demonstrated to be regulated by auxin response factors (ARFs), key transcriptional modulators in the auxin signaling pathway. However, the role of this class of transcription factors (TFs) in perennials with complex seed dormancy mechanisms remains largely unexplored. Here, we cloned and characterized an ARF gene from Paeonia lactiflora, named PlARF2, which exhibited differential expression levels in the seeds during the process of seed dormancy release. The deduced amino acid sequence of PlARF2 had high homology with those of other plants and contained typical conserved Auxin_resp domain of the ARF family. Phylogenetic analysis revealed that PlARF2 was closely related to VvARF3 in Vitis vinifera. The subcellular localization and transcriptional activation assay showed that PlARF2 is a nuclear protein possessing transcriptional activation activity. The expression levels of dormancy-related genes in transgenic callus indicated that PlARF2 was positively correlated with the contents of PlABI3 and PlDOG1. The germination assay showed that PlARF2 promoted seed dormancy. Moreover, TF Centered Yeast one-hybrid assay (TF-Centered Y1H), electrophoretic mobility shift assay (EMSA) and dual-luciferase reporter assay analysis (Dual-Luciferase) provided evidence that PlARF2 can bind to the 'CATGCATG' motif. Collectively, our findings suggest that PlARF2, as TF, could be involved in the regulation of seed dormancy and may act as a repressor of germination.
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Affiliation(s)
- Siyang Duan
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China
| | - Shixin Guan
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China
| | - Riwen Fei
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China
| | - Tianyi Sun
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China
| | - Xuening Kang
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China
| | - Rujie Xin
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China
| | - Wenhui Song
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China
| | - Xiaomei Sun
- College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China.
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, 110866, China.
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2
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Otálora-Otálora BA, López-Rivera JJ, Aristizábal-Guzmán C, Isaza-Ruget MA, Álvarez-Moreno CA. Host Transcriptional Regulatory Genes and Microbiome Networks Crosstalk through Immune Receptors Establishing Normal and Tumor Multiomics Metafirm of the Oral-Gut-Lung Axis. Int J Mol Sci 2023; 24:16638. [PMID: 38068961 PMCID: PMC10706695 DOI: 10.3390/ijms242316638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/13/2023] [Accepted: 11/18/2023] [Indexed: 12/18/2023] Open
Abstract
The microbiome has shown a correlation with the diet and lifestyle of each population in health and disease, the ability to communicate at the cellular level with the host through innate and adaptative immune receptors, and therefore an important role in modulating inflammatory process related to the establishment and progression of cancer. The oral cavity is one of the most important interaction windows between the human body and the environment, allowing the entry of an important number of microorganisms and their passage across the gastrointestinal tract and lungs. In this review, the contribution of the microbiome network to the establishment of systemic diseases like cancer is analyzed through their synergistic interactions and bidirectional crosstalk in the oral-gut-lung axis as well as its communication with the host cells. Moreover, the impact of the characteristic microbiota of each population in the formation of the multiomics molecular metafirm of the oral-gut-lung axis is also analyzed through state-of-the-art sequencing techniques, which allow a global study of the molecular processes involved of the flow of the microbiota environmental signals through cancer-related cells and its relationship with the establishment of the transcription factor network responsible for the control of regulatory processes involved with tumorigenesis.
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Affiliation(s)
| | - Juan Javier López-Rivera
- Grupo de Investigación INPAC, Specialized Laboratory, Clinica Universitaria Colombia, Clínica Colsanitas S.A., Bogotá 111321, Colombia;
| | - Claudia Aristizábal-Guzmán
- Grupo de Investigación INPAC, Unidad de Investigación, Fundación Universitaria Sanitas, Bogotá 110131, Colombia;
| | - Mario Arturo Isaza-Ruget
- Keralty, Sanitas International Organization, Grupo de Investigación INPAC, Fundación Universitaria Sanitas, Bogotá 110131, Colombia;
| | - Carlos Arturo Álvarez-Moreno
- Infectious Diseases Department, Clinica Universitaria Colombia, Clínica Colsanitas S.A., Bogotá 111321, Colombia;
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3
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Schultz D, Stevanovic M, Tsimring LS. Optimal transcriptional regulation of dynamic bacterial responses to sudden drug exposures. Biophys J 2022; 121:4137-4152. [PMID: 36168291 PMCID: PMC9675034 DOI: 10.1016/j.bpj.2022.09.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/22/2022] [Accepted: 09/23/2022] [Indexed: 11/17/2022] Open
Abstract
Cellular responses to the presence of toxic compounds in their environment require prompt expression of the correct levels of the appropriate enzymes, which are typically regulated by transcription factors that control gene expression for the duration of the response. The characteristics of each response dictate the choice of regulatory parameters such as the affinity of the transcription factor to its binding sites and the strength of the promoters it regulates. Although much is known about the dynamics of cellular responses, we still lack a framework to understand how different regulatory strategies evolved in natural systems relate to the selective pressures acting in each particular case. Here, we analyze a dynamical model of a typical antibiotic response in bacteria, where a transcriptionally repressed enzyme is induced by a sudden exposure to the drug that it processes. We identify strategies of gene regulation that optimize this response for different types of selective pressures, which we define as a set of costs associated with the drug, enzyme, and repressor concentrations during the response. We find that regulation happens in a limited region of the regulatory parameter space. While responses to more costly (toxic) drugs favor the usage of strongly self-regulated repressors, responses where expression of enzyme is more costly favor the usage of constitutively expressed repressors. Only a very narrow range of selective pressures favor weakly self-regulated repressors. We use this framework to determine which costs and benefits are most critical for the evolution of a variety of natural cellular responses that satisfy the approximations in our model and to analyze how regulation is optimized in new environments with different demands.
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Affiliation(s)
- Daniel Schultz
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
| | - Mirjana Stevanovic
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Lev S Tsimring
- Synthetic Biology Institute, University of California, San Diego, La Jolla, California
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4
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Zaheri B, Morse D. An overview of transcription in dinoflagellates. Gene 2022; 829:146505. [PMID: 35447242 DOI: 10.1016/j.gene.2022.146505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 02/18/2022] [Accepted: 04/14/2022] [Indexed: 11/25/2022]
Abstract
Dinoflagellates are a vital diverse family of unicellular algae widespread in various aquatic environments. Typically large genomes and permanently condensed chromosomes without histones make these organisms unique among eukaryotes in terms of chromatin structure and gene expression. Genomic and transcriptomic sequencing projects have provided new insight into the genetic foundation of dinoflagellate behaviors. Genes in tandem arrays, trans-splicing of mRNAs and lower levels of transcriptional regulation compared to other eukaryotes all contribute to the differences seen. Here we present a general overview of transcription in dinoflagellates based on previously described work.
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Affiliation(s)
- Bahareh Zaheri
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, 4101 Sherbrooke est, Université de Montréal, Montréal H1X 2B2, Canada
| | - David Morse
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, 4101 Sherbrooke est, Université de Montréal, Montréal H1X 2B2, Canada.
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5
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Grechnikova M, Arbon D, Ženíšková K, Malych R, Mach J, Krejbichová L, Šimáčková A, Sutak R. Elucidation of iron homeostasis in Acanthamoeba castellanii. Int J Parasitol 2022; 52:497-508. [PMID: 35533729 DOI: 10.1016/j.ijpara.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/21/2022] [Accepted: 03/27/2022] [Indexed: 11/25/2022]
Abstract
Acanthamoeba castellanii is a ubiquitously distributed amoeba that can be found in soil, dust, natural and tap water, air conditioners, hospitals, contact lenses and other environments. It is an amphizoic organism that can cause granulomatous amoebic encephalitis, an infrequent fatal disease of the central nervous system, and amoebic keratitis, a severe corneal infection that can lead to blindness. These diseases are extremely hard to treat; therefore, a more comprehensive understanding of this pathogen's metabolism is essential for revealing potential therapeutic targets. To propagate successfully in human tissues, the parasites must resist the iron depletion caused by nutritional immunity. The aim of our study is to elucidate the mechanisms underlying iron homeostasis in A. castellanii. Using a comparative whole-cell proteomic analysis of cells grown under different degrees of iron availability, we identified the primary proteins involved in Acanthamoeba iron acquisition. Our results suggest a two-step reductive mechanism of iron acquisition by a ferric reductase from the STEAP family and a divalent metal transporter from the NRAMP family. Both proteins are localized to the membranes of acidified digestive vacuoles where endocytosed medium and bacteria are trafficked. The expression levels of these proteins are significantly higher under iron-limited conditions, which allows Acanthamoeba to increase the efficiency of iron uptake despite the observed reduced pinocytosis rate. We propose that excessive iron gained while grown under iron-rich conditions is removed from the cytosol into the vacuoles by an iron transporter homologous to VIT/Ccc1 proteins. Additionally, we identified a novel protein that may participate in iron uptake regulation, the overexpression of which leads to increased iron acquisition.
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Affiliation(s)
- Maria Grechnikova
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Dominik Arbon
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Kateřina Ženíšková
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Ronald Malych
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Jan Mach
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Lucie Krejbichová
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Aneta Šimáčková
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Robert Sutak
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic.
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6
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Hassani D, Fu X, Shen Q, Khalid M, Rose JKC, Tang K. Parallel Transcriptional Regulation of Artemisinin and Flavonoid Biosynthesis. TRENDS IN PLANT SCIENCE 2020; 25:466-476. [PMID: 32304658 DOI: 10.1016/j.tplants.2020.01.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 11/27/2019] [Accepted: 01/13/2020] [Indexed: 06/11/2023]
Abstract
Plants regulate the synthesis of specialized compounds through the actions of individual transcription factors (TFs) or sets of TFs. One such compound, artemisinin from Artemisia annua, is widely used as a pharmacological product in the first-line treatment of malaria. However, the emergence of resistance to artemisinin in Plasmodium species, as well as its low production rates, have required innovative treatments such as exploiting the synergistic effects of flavonoids with artemisinin. We overview current knowledge about flavonoid and artemisinin transcriptional regulation in A. annua, and review the dual action of TFs and structural genes that can regulate both pathways simultaneously. Understanding the concerted action of these TFs and their associated structural genes can guide the development of strategies to further improve flavonoid and artemisinin production.
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Affiliation(s)
- Danial Hassani
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University (SJTU), Shanghai 200240, China
| | - Xueqing Fu
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University (SJTU), Shanghai 200240, China
| | - Qian Shen
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University (SJTU), Shanghai 200240, China
| | - Muhammad Khalid
- Key Laboratory of Urban Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jocelyn K C Rose
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Kexuan Tang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University (SJTU), Shanghai 200240, China.
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7
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Guo J, Ling N, Chen Z, Xue C, Li L, Liu L, Gao L, Wang M, Ruan J, Guo S, Vandenkoornhuyse P, Shen Q. Soil fungal assemblage complexity is dependent on soil fertility and dominated by deterministic processes. THE NEW PHYTOLOGIST 2020; 225:1618-1634. [PMID: 31574168 DOI: 10.1111/nph.16233] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/23/2019] [Indexed: 05/18/2023]
Abstract
In the processes controlling ecosystem fertility, fungi are increasingly acknowledged as key drivers. However, our understanding of the rules behind fungal community assembly regarding the effect of soil fertility level remains limited. Using soil samples from typical tea plantations spanning c. 2167 km north-east to south-west across China, we investigated the assemblage complexity and assembly processes of 140 fungal communities along a soil fertility gradient. The community dissimilarities of total fungi and fungal functional guilds increased with increasing soil fertility index dissimilarity. The symbiotrophs were more sensitive to variations in soil fertility compared with pathotrophs and saprotrophs. Fungal networks were larger and showed higher connectivity as well as greater potential for inter-module connection in more fertile soils. Environmental factors had a slightly greater influence on fungal community composition than spatial factors. Species abundance fitted the Zipf-Mandelbrot distribution (niche-based mechanisms), which provided evidence for deterministic-based processes. Overall, the soil fungal communities in tea plantations responded in a deterministic manner to soil fertility, with high fertility correlated with complex fungal community assemblages. This study provides new insights that might contribute to predictions of fungal community complexity.
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Affiliation(s)
- Junjie Guo
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ning Ling
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
- UMR 6553 EcoBio, Universite de Rennes 1, CNRS, campus Beaulieu, Avenue du Général Leclerc, 35042, Rennes Cedex, France
| | - Zhaojie Chen
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chao Xue
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ling Li
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Lisheng Liu
- Hengyang Red Soil Experimental Station, Chinese Academy of Agricultural Sciences, Hengyang, 421001, China
| | - Limin Gao
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Min Wang
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianyun Ruan
- Key Laboratory of Tea Plant Biology and Resources Utilization (Ministry of Agriculture), Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China
| | - Shiwei Guo
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
| | - Philippe Vandenkoornhuyse
- UMR 6553 EcoBio, Universite de Rennes 1, CNRS, campus Beaulieu, Avenue du Général Leclerc, 35042, Rennes Cedex, France
| | - Qirong Shen
- Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, 210095, China
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8
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Abstract
The transport of proteins between the nucleus and the cytosol is a vital process regulating cellular activity. The ability to spatiotemporally control the nucleocytoplasmic transport of a protein of interest allows for elucidating its function taking into account the dynamic and heterogeneous nature of biological processes contrary to conventional knockin, knockout, and chemically induced overexpression strategies. We recently developed two optogenetic tools, called LINuS and LEXY, for reversibly controlling with blue light the nuclear import and export of proteins of interest, respectively. Here we describe how to use them to control the localization of a protein of interest in cultured mammalian cells using a fluorescence microscope.
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Affiliation(s)
- Daniel Weis
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Barbara Di Ventura
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany. .,Institute of Biology II, University of Freiburg, Freiburg, Germany.
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9
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Nair A, Chauhan P, Saha B, Kubatzky KF. Conceptual Evolution of Cell Signaling. Int J Mol Sci 2019; 20:E3292. [PMID: 31277491 PMCID: PMC6651758 DOI: 10.3390/ijms20133292] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/26/2019] [Accepted: 06/28/2019] [Indexed: 12/27/2022] Open
Abstract
During the last 100 years, cell signaling has evolved into a common mechanism for most physiological processes across systems. Although the majority of cell signaling principles were initially derived from hormonal studies, its exponential growth has been supported by interdisciplinary inputs, e.g., from physics, chemistry, mathematics, statistics, and computational fields. As a result, cell signaling has grown out of scope for any general review. Here, we review how the messages are transferred from the first messenger (the ligand) to the receptor, and then decoded with the help of cascades of second messengers (kinases, phosphatases, GTPases, ions, and small molecules such as cAMP, cGMP, diacylglycerol, etc.). The message is thus relayed from the membrane to the nucleus where gene expression ns, subsequent translations, and protein targeting to the cell membrane and other organelles are triggered. Although there are limited numbers of intracellular messengers, the specificity of the response profiles to the ligands is generated by the involvement of a combination of selected intracellular signaling intermediates. Other crucial parameters in cell signaling are its directionality and distribution of signaling strengths in different pathways that may crosstalk to adjust the amplitude and quality of the final effector output. Finally, we have reflected upon its possible developments during the coming years.
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Affiliation(s)
- Arathi Nair
- National Center for Cell Science (NCCS), Ganeshkhind, Pune 411007, India
| | - Prashant Chauhan
- National Center for Cell Science (NCCS), Ganeshkhind, Pune 411007, India
| | - Bhaskar Saha
- National Center for Cell Science (NCCS), Ganeshkhind, Pune 411007, India.
| | - Katharina F Kubatzky
- Zentrum für Infektiologie, Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
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10
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Leake MC. Transcription factors in eukaryotic cells can functionally regulate gene expression by acting in oligomeric assemblies formed from an intrinsically disordered protein phase transition enabled by molecular crowding. Transcription 2018; 9:298-306. [PMID: 29895219 PMCID: PMC6150617 DOI: 10.1080/21541264.2018.1475806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
High-speed single-molecule fluorescence microscopy in vivo shows that transcription factors in eukaryotes can act in oligomeric clusters mediated by molecular crowding and intrinsically disordered protein. This finding impacts on the longstanding puzzle of how transcription factors find their gene targets so efficiently in the complex, heterogeneous environment of the cell. Abbreviations CDF - cumulative distribution function; FRAP - fluorescence recovery after photobleaching; GFP - Green fluorescent protein; STORM - stochastic optical reconstruction microscopy; TF - Transcription factor; YFP - Yellow fluorescent protein
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Affiliation(s)
- Mark C Leake
- a Departments of Physics and Biology , Biological Physical Sciences Institute, University of York , York , UK
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11
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Schrenk C, Fetz V, Vallet C, Heiselmayer C, Schröder E, Hensel A, Hahlbrock A, Wünsch D, Goesswein D, Bier C, Habtemichael N, Schneider G, Stauber RH, Knauer SK. TFIIA transcriptional activity is controlled by a 'cleave-and-run' Exportin-1/Taspase 1-switch. J Mol Cell Biol 2018; 10:33-47. [PMID: 28992066 DOI: 10.1093/jmcb/mjx025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/09/2017] [Indexed: 12/24/2022] Open
Abstract
Transcription factor TFIIA is controlled by complex regulatory networks including proteolysis by the protease Taspase 1, though the full impact of cleavage remains elusive. Here, we demonstrate that in contrast to the general assumption, de novo produced TFIIA is rapidly confined to the cytoplasm via an evolutionary conserved nuclear export signal (NES, amino acids 21VINDVRDIFL30), interacting with the nuclear export receptor Exportin-1/chromosomal region maintenance 1 (Crm1). Chemical export inhibition or genetic inactivation of the NES not only promotes TFIIA's nuclear localization but also affects its transcriptional activity. Notably, Taspase 1 processing promotes TFIIA's nuclear accumulation by NES masking, and modulates its transcriptional activity. Moreover, TFIIA complex formation with the TATA box binding protein (TBP) is cooperatively enhanced by inhibition of proteolysis and nuclear export, leading to an increase of the cell cycle inhibitor p16INK, which is counteracted by prevention of TBP binding. We here identified a novel mechanism how proteolysis and nuclear transport cooperatively fine-tune transcriptional programs.
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Affiliation(s)
- Christian Schrenk
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Verena Fetz
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Cecilia Vallet
- Molecular Biology, Centre for Medical Biotechnology (ZMB), University Duisburg-Essen, 45141 Essen, Germany
| | - Christina Heiselmayer
- Molecular Biology, Centre for Medical Biotechnology (ZMB), University Duisburg-Essen, 45141 Essen, Germany
| | - Elisabeth Schröder
- Molecular Biology, Centre for Medical Biotechnology (ZMB), University Duisburg-Essen, 45141 Essen, Germany
| | - Astrid Hensel
- Molecular Biology, Centre for Medical Biotechnology (ZMB), University Duisburg-Essen, 45141 Essen, Germany
| | - Angelina Hahlbrock
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Désirée Wünsch
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Dorothee Goesswein
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Carolin Bier
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Negusse Habtemichael
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Günter Schneider
- University Hospital Klinikum rechts der Isar, II. Medizinische Klinik, Technical University München, 81675 Munich, Germany
| | - Roland H Stauber
- Molecular and Cellular Oncology/ENT, University Hospital of Mainz, 55101 Mainz, Germany
| | - Shirley K Knauer
- Molecular Biology, Centre for Medical Biotechnology (ZMB), University Duisburg-Essen, 45141 Essen, Germany
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12
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Gribko A, Hahlbrock A, Strieth S, Becker S, Hagemann J, Deichelbohrer M, Hildebrandt A, Habtemichael N, Wünsch D. Disease-relevant signalling-pathways in head and neck cancer: Taspase1's proteolytic activity fine-tunes TFIIA function. Sci Rep 2017; 7:14937. [PMID: 29097782 PMCID: PMC5668323 DOI: 10.1038/s41598-017-14814-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/16/2017] [Indexed: 12/23/2022] Open
Abstract
Head and neck cancer (HNC) is the seventh most common malignancy in the world and its prevailing form, the head and neck squamous cell carcinoma (HNSCC), is characterized as aggressive and invasive cancer type. The transcription factor II A (TFIIA), initially described as general regulator of RNA polymerase II-dependent transcription, is part of complex transcriptional networks also controlling mammalian head morphogenesis. Posttranslational cleavage of the TFIIA precursor by the oncologically relevant protease Taspase1 is crucial in this process. In contrast, the relevance of Taspase1-mediated TFIIA cleavage during oncogenesis of HNSCC is not characterized yet. Here, we performed genome-wide expression profiling of HNSCC which revealed significant downregulation of the TFIIA downstream target CDKN2A. To identify potential regulatory mechanisms of TFIIA on cellular level, we characterized nuclear-cytoplasmic transport and Taspase1-mediated cleavage of TFIIA variants. Unexpectedly, we identified an evolutionary conserved nuclear export signal (NES) counteracting nuclear localization and thus, transcriptional activity of TFIIA. Notably, proteolytic processing of TFIIA by Taspase1 was found to mask the NES, thereby promoting nuclear localization and transcriptional activation of TFIIA target genes, such as CDKN2A. Collectively, we here describe a hitherto unknown mechanism how cellular localization and Taspase1 cleavage fine-tunes transcriptional activity of TFIIA in HNSCC.
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Affiliation(s)
- Alena Gribko
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany
| | - Angelina Hahlbrock
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany
| | - Sebastian Strieth
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany
| | - Sven Becker
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany
| | - Jan Hagemann
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany
| | - Max Deichelbohrer
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany
| | - Andreas Hildebrandt
- Scientific Computing and Bioinformatics, Johannes Gutenberg University, Staudingerweg 9, Mainz, 55128, Germany
| | - Negusse Habtemichael
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany
| | - D Wünsch
- Department of Otorhinolaryngology, Molecular and Cellular Oncology, University Hospital of Mainz, Langenbeckstrasse 1, Mainz, 55101, Germany.
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Wu Q, Liu X, Yin D, Yuan H, Xie Q, Zhao X, Li X, Zhu L, Li S, Li D. Constitutive expression of OsDof4, encoding a C 2-C 2 zinc finger transcription factor, confesses its distinct flowering effects under long- and short-day photoperiods in rice (Oryza sativa L.). BMC PLANT BIOLOGY 2017; 17:166. [PMID: 29052517 PMCID: PMC5649077 DOI: 10.1186/s12870-017-1109-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 10/04/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND Dof (DNA binding with one finger) proteins, a class of plant-specific transcription factors which contain a conserved C2-C2-type zinc finger domain, are involved in many fundamental processes. In the Arabidopsis photoperiod response pathway, CDF (CYCLING DOF FACTOR) proteins have a primary role as acting via transcriptional repression of the direct FLOWERING LOCUS T (FT) activator CONSTANS (CO). Our previous study indicated that one of CDF homologs, OsDOf12, was involved in photoperiodic flowering. However, the functional characterization of other rice CDF like genes is still in progress. Here, we characterized the function of OsDof4 in rice. RESULTS Phylogenic analysis indicated that OsDof4 is closely clustered into the same subgroup with CDFs and OsDof12. The subcellular localization experiment and transcriptional activity assay suggested that OsDof4 may function as a transcription factor. The diurnal expression pattern indicated that OsDof4 was regulated by endogenous circadian clock. Overexpression of OsDof4 led to earlier flowering under natural long-day field conditions (NLDs) and late flowering under natural short-day field conditions (NSDs), respectively. We compared the expression level of key floral genes in vector line and OsDof4-ox lines grown under long-day conditions (LDs) and short-day conditions (SDs). Real-time q-PCR results demonstrated that under LDs, Hd3a, RFT1 and Ehd1 were up-regulated whereas under SDs they were down-regulated. Hd1 was down-regulated at dusk period independent of photoperiods. CONCLUSIONS Taken these results together, we may speculate that the abnormal flowering responses in OsDof4-ox plants under LDs and SDs might be mediated by Ehd1 and Hd1.
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Affiliation(s)
- Qi Wu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China
- Rice Research Institute, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, 611130, China
- National Research and Development Center for Coarse Cereal Processing, College of Pharmacy and Biological Engineering, Chengdu University, Chengdu, 610106, China
| | - Xue Liu
- Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Dedong Yin
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Hua Yuan
- Rice Research Institute, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, 611130, China
| | - Qi Xie
- Institute of Turfgrass Science, College of Forestry, Beijing Forestry University, Beijing, 100083, China
| | - Xianfeng Zhao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Xiaobing Li
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Lihuang Zhu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Shigui Li
- Rice Research Institute, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, 611130, China.
| | - Dayong Li
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China.
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14
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Wollman AJ, Shashkova S, Hedlund EG, Friemann R, Hohmann S, Leake MC. Transcription factor clusters regulate genes in eukaryotic cells. eLife 2017; 6:27451. [PMID: 28841133 PMCID: PMC5602325 DOI: 10.7554/elife.27451] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/24/2017] [Indexed: 01/07/2023] Open
Abstract
Transcription is regulated through binding factors to gene promoters to activate or repress expression, however, the mechanisms by which factors find targets remain unclear. Using single-molecule fluorescence microscopy, we determined in vivo stoichiometry and spatiotemporal dynamics of a GFP tagged repressor, Mig1, from a paradigm signaling pathway of Saccharomyces cerevisiae. We find the repressor operates in clusters, which upon extracellular signal detection, translocate from the cytoplasm, bind to nuclear targets and turnover. Simulations of Mig1 configuration within a 3D yeast genome model combined with a promoter-specific, fluorescent translation reporter confirmed clusters are the functional unit of gene regulation. In vitro and structural analysis on reconstituted Mig1 suggests that clusters are stabilized by depletion forces between intrinsically disordered sequences. We observed similar clusters of a co-regulatory activator from a different pathway, supporting a generalized cluster model for transcription factors that reduces promoter search times through intersegment transfer while stabilizing gene expression.
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Affiliation(s)
- Adam Jm Wollman
- Biological Physical Sciences Institute, University of York, York, United Kingdom
| | - Sviatlana Shashkova
- Biological Physical Sciences Institute, University of York, York, United Kingdom.,Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Erik G Hedlund
- Biological Physical Sciences Institute, University of York, York, United Kingdom
| | - Rosmarie Friemann
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Stefan Hohmann
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.,Department of Biology and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden
| | - Mark C Leake
- Biological Physical Sciences Institute, University of York, York, United Kingdom
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Abstract
Recently, the existence of a mechanism for neo-oogenesis in the ovaries of adult mammals has generated much controversy within reproductive biology. This mechanism, which proposes that the ovary has cells capable of renewing the follicular reserve, has been described for various species of mammals. The first evidence was found in prosimians and humans. However, these findings were not considered relevant because the predominant dogma for reproductive biology at the time was that of Zuckerman. This dogma states that female mammals are born with finite numbers of oocytes that decline throughout postnatal life. Currently, the concept of neo-oogenesis has gained momentum due to the discovery of cells with mitotic activity in adult ovaries of various mammalian species (mice, humans, rhesus monkeys, domestic animals such as pigs, and wild animals such as bats). Despite these reports, the concept of neo-oogenesis has not been widely accepted by the scientific community, generating much criticism and speculation about its accuracy because it has been impossible to reproduce some evidence. This controversy has led to the creation of two positions: one in favour of neo-oogenesis and the other against it. Various animal models have been used in support of both camps, including both classic laboratory animals and domestic and wild animals. The aim of this review is to critically present the current literature on the subject and to evaluate the arguments pro and contra neo-oogenesis in mammals.
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16
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Redchuk TA, Omelina ES, Chernov KG, Verkhusha VV. Near-infrared optogenetic pair for protein regulation and spectral multiplexing. Nat Chem Biol 2017; 13:633-639. [PMID: 28346403 DOI: 10.1038/nchembio.2343] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/10/2017] [Indexed: 12/18/2022]
Abstract
Multifunctional optogenetic systems are in high demand for use in basic and biomedical research. Near-infrared-light-inducible binding of bacterial phytochrome BphP1 to its natural PpsR2 partner is beneficial for simultaneous use with blue-light-activatable tools. However, applications of the BphP1-PpsR2 pair are limited by the large size, multidomain structure and oligomeric behavior of PpsR2. Here, we engineered a single-domain BphP1 binding partner, Q-PAS1, which is three-fold smaller and lacks oligomerization. We exploited a helix-PAS fold of Q-PAS1 to develop several near-infrared-light-controllable transcription regulation systems, enabling either 40-fold activation or inhibition. The light-induced BphP1-Q-PAS1 interaction allowed modification of the chromatin epigenetic state. Multiplexing the BphP1-Q-PAS1 pair with a blue-light-activatable LOV-domain-based system demonstrated their negligible spectral crosstalk. By integrating the Q-PAS1 and LOV domains in a single optogenetic tool, we achieved tridirectional protein targeting, independently controlled by near-infrared and blue light, thus demonstrating the superiority of Q-PAS1 for spectral multiplexing and engineering of multicomponent systems.
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Affiliation(s)
- Taras A Redchuk
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Evgeniya S Omelina
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Konstantin G Chernov
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Vladislav V Verkhusha
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Department of Anatomy and Structural Biology and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, USA
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17
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Bilgin B, Nath A, Chan C, Walton SP. Characterization of transcription factor response kinetics in parallel. BMC Biotechnol 2016; 16:62. [PMID: 27557669 PMCID: PMC4997724 DOI: 10.1186/s12896-016-0293-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 08/16/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Transcription factors (TFs) are effectors of cell signaling pathways that regulate gene expression. TF networks are highly interconnected; one signal can lead to changes in many TF levels, and one TF level can be changed by many different signals. TF regulation is central to normal cell function, with altered TF function being implicated in many disease conditions. Thus, measuring TF levels in parallel, and over time, is crucial for understanding the impact of stimuli on regulatory networks and on diseases. RESULTS Here, we report the parallel analysis of temporal TF level changes due to multiple stimuli in distinct cell types. We have analyzed short-term dynamic changes in the levels of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), signal transducer and activator of transcription 3 (Stat3), cAMP response element-binding protein (CREB), glucocorticoid receptor (GR), and TATA binding protein (TBP), in breast and liver cancer cells after tumor necrosis factor-alpha (TNF-α) and palmitic acid (PA) exposure. In response to both stimuli, NF-kB and CREB levels were increased, Stat3 decreased, and TBP was constant. GR levels were unchanged in response to TNF-α stimulation and increased in response to PA treatment. CONCLUSIONS Our results show significant overlap in signaling initiated by TNF-α and by PA, with the exception that the events leading to PA-mediated cytotoxicity likely also include induction of GR signaling. These results further illuminate the dynamics of TF responses to cytokine and fatty acid exposure, while concomitantly demonstrating the utility of parallel TF measurement approaches in the analysis of biological phenomena.
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Affiliation(s)
- Betul Bilgin
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S. Shaw Lane, Room 3249, Engineering Building, East Lansing, MI 48824-1226 USA
| | - Aritro Nath
- Genetics Program, Michigan State University, East Lansing, MI 48824 USA
| | - Christina Chan
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S. Shaw Lane, Room 3249, Engineering Building, East Lansing, MI 48824-1226 USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
| | - S. Patrick Walton
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S. Shaw Lane, Room 3249, Engineering Building, East Lansing, MI 48824-1226 USA
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18
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Zhang X, An L, Nguyen TH, Liang H, Wang R, Liu X, Li T, Qi Y, Yu F. The Cloning and Functional Characterization of Peach CONSTANS and FLOWERING LOCUS T Homologous Genes PpCO and PpFT. PLoS One 2015; 10:e0124108. [PMID: 25905637 PMCID: PMC4408105 DOI: 10.1371/journal.pone.0124108] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/26/2015] [Indexed: 11/21/2022] Open
Abstract
Flowering is an essential stage of plant growth and development. The successful transition to flowering not only ensures the completion of plant life cycles, it also serves as the basis for the production of economically important seeds and fruits. CONSTANS (CO) and FLOWERING LOCUS T (FT) are two genes playing critical roles in flowering time control in Arabidopsis. Through homology-based cloning and rapid-amplifications of cDNA ends (RACE), we obtained full-lengths cDNA sequences of Prunus persica CO (PpCO) and Prunus persica FT (PpFT) from peach (Prunus persica (L.) Batsch) and investigated their functions in flowering time regulation. PpCO and PpFT showed high homologies to Arabidopsis CO and FT at DNA, mRNA and protein levels. We showed that PpCO and PpFT were nucleus-localized and both showed transcriptional activation activities in yeast cells, consistent with their potential roles as transcription activators. Moreover, we established that the over-expression of PpCO could restore the late flowering phenotype of the Arabidopsis co-2 mutant, and the late flowering defect of the Arabidopsis ft-1 mutant can be rescued by the over-expression of PpFT, suggesting functional conservations of CO and FT genes in peach and Arabidopsis. Our results suggest that PpCO and PpFT are homologous genes of CO and FT in peach and they may function in regulating plant flowering time.
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Affiliation(s)
- Xiang Zhang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
| | - Lijun An
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
| | - Thi Hung Nguyen
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
| | - Huike Liang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
| | - Rui Wang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
| | - Xiayan Liu
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
| | - Tianhong Li
- Department of Fruit Science, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, People’s Republic of China
| | - Yafei Qi
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
| | - Fei Yu
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, People’s Republic of China
- * E-mail:
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19
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Javadov S, Jang S, Agostini B. Crosstalk between mitogen-activated protein kinases and mitochondria in cardiac diseases: therapeutic perspectives. Pharmacol Ther 2014; 144:202-25. [PMID: 24924700 DOI: 10.1016/j.pharmthera.2014.05.013] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/30/2014] [Indexed: 02/07/2023]
Abstract
Cardiovascular diseases cause more mortality and morbidity worldwide than any other diseases. Although many intracellular signaling pathways influence cardiac physiology and pathology, the mitogen-activated protein kinase (MAPK) family has garnered significant attention because of its vast implications in signaling and crosstalk with other signaling networks. The extensively studied MAPKs ERK1/2, p38, JNK, and ERK5, demonstrate unique intracellular signaling mechanisms, responding to a myriad of mitogens and stressors and influencing the signaling of cardiac development, metabolism, performance, and pathogenesis. Definitive relationships between MAPK signaling and cardiac dysfunction remain elusive, despite 30 years of extensive clinical studies and basic research of various animal/cell models, severities of stress, and types of stimuli. Still, several studies have proven the importance of MAPK crosstalk with mitochondria, powerhouses of the cell that provide over 80% of ATP for normal cardiomyocyte function and play a crucial role in cell death. Although many questions remain unanswered, there exists enough evidence to consider the possibility of targeting MAPK-mitochondria interactions in the prevention and treatment of heart disease. The goal of this review is to integrate previous studies into a discussion of MAPKs and MAPK-mitochondria signaling in cardiac diseases, such as myocardial infarction (ischemia), hypertrophy and heart failure. A comprehensive understanding of relevant molecular mechanisms, as well as challenges for studies in this area, will facilitate the development of new pharmacological agents and genetic manipulations for therapy of cardiovascular diseases.
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Affiliation(s)
- Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, PR, USA.
| | - Sehwan Jang
- Department of Physiology, School of Medicine, University of Puerto Rico, PR, USA
| | - Bryan Agostini
- Department of Physiology, School of Medicine, University of Puerto Rico, PR, USA
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20
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Abstract
SummaryFor decades, scientists have considered that female mammals are born with a lifetime reserve of oocytes in the ovary, irrevocably fated to decline after birth. However, controversy in the matter of the possible presence of oocytes and granulosa cells that originate from stem cells in the adult mammalian ovaries has been expanded. The restricted supply of oocytes in adult female mammals has been disputed in recent years by supporters of neo-oogenesis, who claim that germline stem cells (GSCs) exist in the ovarian surface epithelium (OSE) or the bone marrow (BM). Differentiation of ovarian stem cells (OSCs) into oocytes, fibroblast-like cells, granulosa phenotype, neural and mesenchymal type cells and generation of germ cells from OSCs under the contribution of an OSC niche that consists of immune system-related cells and hormonal signalling has been claimed. Although these arguments have met with intense suspicion, their confirmation would necessitate the revision of the current classic knowledge of female reproductive biology.
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21
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An appraisal of the therapeutic value of lycopene for the chemoprevention of prostate cancer: A nutrigenomic approach. Food Res Int 2013. [DOI: 10.1016/j.foodres.2013.03.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Zhao Y, Xiao J, Gong S, Clara JA, Ledoux MS. Neural expression of the transcription factor THAP1 during development in rat. Neuroscience 2012; 231:282-95. [PMID: 23219941 DOI: 10.1016/j.neuroscience.2012.11.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/24/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
Abstract
Loss of function mutations in THAP1 has been associated with primary generalized and focal dystonia in children and adults. THAP1 encodes a transcription factor (THAP1) that harbors an atypical zinc finger domain and plays a critical role in G(1)-S cell cycle control. Current thinking suggests that dystonia may be a neurodevelopmental circuit disorder. Hence, THAP1 may participate in the development of the nervous system. Herein, we report the neurodevelopmental expression patterns of Thap1 transcript and THAP1 protein from the early postnatal period through adulthood in the rat brain, spinal cord and dorsal root ganglia (DRG). We detected Thap1 transcript and THAP1-immunoreactivity (IR) in the cerebral cortex, cerebellum, striatum, substantia nigra, thalamus, spinal cord and DRG. Thap1 transcript expression was higher in the brain than in spinal cord and DRG at P1 and P7 and declined to similar levels at P14 and later time points in all regions except the cerebellum, where it remained high through adulthood. In the brain, THAP1 expression was highest in early development, particularly in the cerebellum at P7. In addition to Purkinje cells in the cerebellum, THAP1-IR was also localized to pyramidal neurons in the cerebral cortex, relay neurons in the thalamus, medium spiny and cholinergic neurons in the striatum, dopaminergic neurons in the substantia nigra, and pyramidal and interneurons in the hippocampus. In the cerebellar cortex, THAP1-IR was prominently distributed in the perikarya and proximal dendrites of Purkinje cells at early time-points. In contrast, it was more diffusely distributed throughout the dendritic arbor of adult Purkinje cells producing a moderate diffuse staining pattern in the molecular layer. At all time points, nuclear IR was weaker than cytoplasmic IR. The prominent cytoplasmic and developmentally regulated expression of THAP1 suggests that THAP1 may function as part of a cell surface-nucleus signaling cascade involved in terminal neural differentiation.
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Affiliation(s)
- Y Zhao
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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23
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Kerro Dego O, Oliver SP, Almeida RA. Host-pathogen gene expression profiles during infection of primary bovine mammary epithelial cells with Escherichia coli strains associated with acute or persistent bovine mastitis. Vet Microbiol 2011; 155:291-7. [PMID: 21917386 DOI: 10.1016/j.vetmic.2011.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/11/2011] [Accepted: 08/16/2011] [Indexed: 01/06/2023]
Abstract
Escherichia coli intramammary infection (IMI) is often acute with local and systemic clinical manifestations that clear within 7 days. However, if not diagnosed early and treated, E. coli IMI could result in generalized systemic reaction and death. Persistent E. coli IMI is characterized by mild clinical manifestations followed by acute episodes of clinical mastitis during lactation. Factors responsible for pathogenesis of E. coli IMI and variation in clinical manifestations are not known. There are studies indicating that the outcome of E. coli IMI is mainly determined by cow factors. However, recent research demonstrated that virulence attributes of E. coli strains have significant impact on the outcome of E. coli IMI. The aims of this study were; (a) to compare gene expression profiles of PBMEC cocultured with strains of E. coli associated with acute or persistent IMI and; (b) to identify genes of E. coli induced during bacterial interaction with PBMEC. Utilizing cDNA we analyzed gene expression patterns of PBMEC cocultured with strains of E. coli using non-treated PBMEC as negative control. We evaluated also expression patterns of virulence associated genes of E. coli after co-culture with PBMEC using qRT-PCR. Our results showed that infection by both strains induced increased expression of pro-inflammatory cytokines, chemokines and innate immune response and apoptosis related genes. Our qRT-PCR results showed significant up-regulation of ler, eae, flic and iutA genes mainly in the strains of E. coli associated with persistent IMI. The pathogenesis and clinical severity of E. coli IMI may be determined by combined effects of host-pathogen factors.
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Affiliation(s)
- O Kerro Dego
- Department of Animal Science, The University of Tennessee, Knoxville, TN 37996, USA
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24
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Transcription factor plasmid binding modulates microtubule interactions and intracellular trafficking during gene transfer. Gene Ther 2011; 19:338-46. [PMID: 21716302 DOI: 10.1038/gt.2011.96] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
For non-viral gene delivery to be successful, plasmids must move through the cytoplasm to the nucleus in order to be transcribed. While the cytoskeletal meshwork acts as a barrier to plasmid DNA movement in the cytoplasm, the microtubule network is required for directed plasmid trafficking to the nucleus. We have shown previously that plasmid-microtubule interactions require cytoplasmic adapter proteins such as molecular motors, transcription factors (TFs) and importins. However, not all plasmid sequences support these interactions to allow movement to the nucleus. We now demonstrate that microtubule-DNA interactions can show sequence specificity with promoters containing binding sites for cyclic AMP response-element binding protein (CREB), including the cytomegalovirus immediate early promoter (CMV(iep)). Plasmids containing CREB-binding sites showed stringent interactions in an in vitro microtubule-binding assay. Using microinjection and real-time particle tracking, we show that the inclusion of TF binding sites within plasmids permits cytoplasmic trafficking of plasmids during gene transfer. We found that CREB-binding sites are bound by CREB in the cytoplasm during transfection, and allow for enhanced rates of movement and subsequent nuclear accumulation. Moreover, small interfering RNA knockdown of CREB prevented this enhanced trafficking. Therefore, TF binding sites within plasmids are necessary for interactions with microtubules and enhance movement to the nucleus.
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25
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Yang CM, Lu IH, Chen HY, Hu ML. Lycopene inhibits the proliferation of androgen-dependent human prostate tumor cells through activation of PPARγ-LXRα-ABCA1 pathway. J Nutr Biochem 2011; 23:8-17. [PMID: 21334870 DOI: 10.1016/j.jnutbio.2010.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 09/24/2010] [Accepted: 10/11/2010] [Indexed: 11/29/2022]
Abstract
The activation of nuclear receptors, peroxisome proliferator-activated receptor gamma (PPARγ) and liver X receptor alpha (LXRα), has been shown to inhibit the growth of prostate cancer cells. This study examined whether the anti-proliferative effect of lycopene on androgen-dependent human prostate cancer (LNCaP) cells involves the up-regulation of the expression of PPARγ and LXRα. As expected, lycopene treatment (2.5-10 μM) significantly inhibited the proliferation of LNCaP cells during incubation for 96 h. Lycopene significantly increased the protein and mRNA expression of PPARγ and LXRα at 24 and 48 h, while the increased in the expression of ATP-binding cassette transporter 1 (ABCA1) was only evident 96 h. In addition, lycopene significantly decreased cellular total cholesterol levels and increased apoA1 protein expression at 96 h. Incubation of LNCaP cells with lycopene (10 μM) in the presence (20 μM) of a specific antagonist of PPARγ (GW9662) and LXRα (GGPP) restored the proliferation of LNCaP cells to the control levels and significantly suppressed protein expression of PPARγ and LXRα as well as increased cellular total cholesterol levels. LXRα knockdown by siRNA against LXRα significantly enhanced the proliferation of LNCaP cells, whereas si-LXRα knockdown followed by incubation with lycopene (10 μM) restored the proliferation to the control level. The present study is the first to demonstrate that the anti-proliferative effect of lycopene on LNCaP cells involves the activation of the PPARγ-LXRα-ABCA1 pathway, leading to reduced cellular total cholesterol levels.
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Affiliation(s)
- Chih-Min Yang
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan 402, ROC
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26
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Hong SY, Kim OK, Kim SG, Yang MS, Park CM. Nuclear import and DNA binding of the ZHD5 transcription factor is modulated by a competitive peptide inhibitor in Arabidopsis. J Biol Chem 2010; 286:1659-68. [PMID: 21059647 PMCID: PMC3020774 DOI: 10.1074/jbc.m110.167692] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Competitive inhibition of transcription factors by small proteins is an intriguing component of gene regulatory networks in both animals and plants. The small interfering proteins possess limited sequence homologies to specific transcription factors but lack one or more protein motifs required for transcription factor activities. They interfere with the activities of transcription factors, such as DNA binding and transcriptional activation, by forming nonfunctional heterodimers. A potential example is the Arabidopsis MIF1 (mini zinc finger 1) protein consisting of 101 residues. It has a zinc finger domain but lacks other protein motifs normally present in transcription factors. In this work, we show that MIF1 and its functional homologues physically interact with a group of zinc finger homeodomain (ZHD) transcription factors, such as ZHD5, that regulate floral architecture and leaf development. Gel mobility shift assays revealed that MIF1 blocks the DNA binding activity of ZHD5 homodimers by competitively forming MIF1-ZHD5 heterodimers. Accordingly, the transcriptional activation activity of ZHD5 was significantly suppressed by MIF1 coexpressed transiently in Arabidopsis protoplasts. Notably, MIF1 also prevents ZHD5 from nuclear localization. Although ZHD5 was localized exclusively in the nucleus, it was scattered throughout the cytoplasm when MIF1 was coexpressed. Transgenic plants overexpressing the ZHD5 gene (35S:ZHD5) exhibited accelerated growth with larger leaves. Consistent with the negative regulation of ZHD5 by MIF1, the 35S:ZHD5 phenotypes were diminished by MIF1 coexpression. These observations indicate that MIF1 regulates the ZHD5 activities in a dual step manner: nuclear import and DNA binding.
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Affiliation(s)
- Shin-Young Hong
- Department of Chemistry, Seoul National University, Seoul 151-742, Korea
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27
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Graf H. Meeting Highlights: CNRS Conference on Drugs Acting on DNA 27 June – 1 July 1994, Aussois, France. Expert Opin Investig Drugs 2008. [DOI: 10.1517/13543784.3.10.1067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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Lutz W, Wasowicz W. Metal-Induced Modulation of Redox Cell-Signaling in the Immune System. ACTA ACUST UNITED AC 2003. [DOI: 10.1080/08865140302422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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29
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Qiu J, Li X, Frank G, Shen B. Cell cycle-dependent and DNA damage-inducible nuclear localization of FEN-1 nuclease is consistent with its dual functions in DNA replication and repair. J Biol Chem 2001; 276:4901-8. [PMID: 11053418 DOI: 10.1074/jbc.m007825200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Flap endonuclease-1 (FEN-1), a 43-kDa protein, is a structure-specific and multifunctional nuclease. It plays important roles in RNA primer removal of Okazaki fragments during DNA replication, DNA base excision repair, and maintenance of genome stability. Three functional motifs of the enzyme were proposed to be responsible for its nuclease activities, interaction with proliferating cell nuclear antigen, and nuclear localization. In this study, we demonstrate in HeLa cells that a signal located at the C terminus (the nuclear localization signal (NLS) motif) facilitates nuclear localization of the enzyme during S phase of the cell cycle and in response to DNA damage. Truncation of the NLS motif prevents migration of the protein from the cytoplasm to the nucleus, while having no effect on the nuclease activities and its proliferating cell nuclear antigen interaction capability. Site-directed mutagenesis further revealed that a mutation of the KRK cluster to three alanine residues completely blocked the localization of FEN-1 into the nucleus, whereas mutagenesis of the KKK cluster led to a partial defect of nuclear localization in HeLa cells without observable phenotype in yeast. Therefore, the KRKXXXXXXXXKKK motif may be a bipartite NLS driving the protein into nuclei. Yeast RAD27Delta cells transformed with human mutant M(krk) survived poorly upon methyl methanesulfonate treatment or when they were incubated at an elevated temperature.
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Affiliation(s)
- J Qiu
- Department of Cell and Tumor Biology, City of Hope National Medical Center, Duarte, CA 91010, USA
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30
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Brzostowski J, Robinson C, Orford R, Elgar S, Scarlett G, Peterkin T, Malartre M, Kneale G, Wormington M, Guille M. RNA-dependent cytoplasmic anchoring of a transcription factor subunit during Xenopus development. EMBO J 2000; 19:3683-93. [PMID: 10899122 PMCID: PMC313978 DOI: 10.1093/emboj/19.14.3683] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2000] [Revised: 05/30/2000] [Accepted: 05/30/2000] [Indexed: 11/14/2022] Open
Abstract
The CCAAT box transcription factor (CBTF) is a multimeric transcription factor that activates expression of the haematopoietic regulatory factor, GATA-2. The 122 kDa subunit of this complex, CBTF(122), is cytoplasmic in fertilized Xenopus eggs and subsequently translocates to the nucleus prior to activation of zygotic GATA-2 transcription at gastrulation. Here we present data suggesting both a role for CBTF(122) prior to its nuclear translocation and the mechanism that retains it in the cytoplasm before the midblastula transition (MBT). CBTF(122) and its variant CBTF(98) are associated with translationally quiescent mRNP complexes. We show that CBTF(122) RNA binding activity is both necessary and sufficient for its cytoplasmic retention during early development. The introduction of an additional nuclear localization signal to CBTF(122) is insufficient to overcome this retention, suggesting that RNA binding acts as a cytoplasmic anchor for CBTF(122). Destruction of endogenous RNA by microinjection of RNase promotes premature nuclear translocation of CBTF(122). Thus, the nuclear translocation of CBTF(122) at the MBT is likely to be coupled to the degradation of maternal mRNA that occurs at that stage.
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Affiliation(s)
- J Brzostowski
- Department of Biology, University of Virginia, Gilmer Hall, Charlottesville, VA 22903-2477, USA
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31
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Zupan J, Muth TR, Draper O, Zambryski P. The transfer of DNA from agrobacterium tumefaciens into plants: a feast of fundamental insights. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 23:11-28. [PMID: 10929098 DOI: 10.1046/j.1365-313x.2000.00808.x] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- J Zupan
- Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, CA 94720-3102, USA
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32
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Alliston TN, Gonzalez-Robayna IJ, Buse P, Firestone GL, Richards JS. Expression and localization of serum/glucocorticoid-induced kinase in the rat ovary: relation to follicular growth and differentiation. Endocrinology 2000; 141:385-95. [PMID: 10614661 DOI: 10.1210/endo.141.1.7257] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Expression of serum/glucocorticoid-inducible kinase (Sgk), one member of an inducible serine/threonine kinase family, is induced by FSH/cAMP in rat granulosa cells cultured in defined medium. The FSH-stimulated pattern of sgk expression is biphasic, and transcriptional activation of the sgk gene depends on an intact Sp1/Sp3 binding site within the proximal promoter. To determine whether sgk was expressed in a hormone-dependent and physiologically relevant manner in vivo, the cellular levels of sgk messenger RNA (mRNA) and protein as well as the subcellular localization of this kinase were analyzed in ovaries containing follicles and corpora lutea at specific stages of differentiation. To stimulate follicular development and luteinization, hypophysectomized (H) rats were treated with estradiol (E; HE) and FSH (FSH; HEF) followed by hCG (hCG; HEF/hCG). To analyze Sgk in functional corpora lutea, PRL was administered to HEF/hCG rats, or ovaries of pregnant rats were obtained on day 7, 15, or 22 of gestation. In situ hybridization indicated that sgk mRNA was low/undetectable in granulosa cells of H and HE rats. An acute injection (i.v.) of FSH to HE rats rapidly increased sgk mRNA at 2 and 8 h. Sgk mRNA was also elevated in granulosa cells of preovulatory follicles of HEF rats and in luteal cells of HEF/hCG and pregnant rats. Northern blots and Western blots confirmed the in situ hybridization data, indicating that the amount and cellular localization Sgk protein were related to that of sgk mRNA. When the subcellular localization of this kinase was analyzed by immunohistochemistry, Sgk protein was nuclear in granulosa cells and some thecal cells of large preovulatory follicles. In contrast, Sgk protein was cytoplasmic in luteal cells as well as some cells within the stromal compartment. Intense immunostaining was also observed in oocytes present in primordial follicles, but not in growing follicles. Collectively, these results show that FSH and LH stimulate marked increases in the cellular content of Sgk, as well as dramatic changes in the subcellular distribution of this kinase. The specific nuclear vs. cytoplasmic compartmentalization of Sgk in granulosa cells and luteal cells, respectively, indicates that Sgk controls distinct functions in proliferative vs. terminally differentiated granulosa cells.
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Affiliation(s)
- T N Alliston
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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33
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Abstract
An increasing body of evidence shows that many of the key inositol lipids and enzymes responsible for their metabolism reside in nuclei. Moreover, the association of the nuclear phosphoinositide cycle with progression through the cell cycle and commitment toward differentiation has built a wider picture of the implications of phosphoinositides in the control of nuclear functions. This article reviews a central aspect of inositide nuclear signaling, i.e., the spatial organization of the signaling system within the nucleus in relationship to the nuclear organization in functional domains. Most of the evidence obtained with a variety of confocal and electron microscopy immunocytochemical techniques indicates that the phosphoinositides, the enzymes required for their synthesis and hydrolysis, and the targets of the lipid second messengers are localized at ribonucleoprotein structures involved in the transcript processing in the interchromatin domains. These findings demonstrate that nuclear inositol lipids exist in a nonmembranous form, linked to structural nuclear proteins of the inner nuclear matrix. They also suggest that the inositol signaling in the nucleus is completely independent of that at the cell surface and that it probably preceded in evolution the systems that are present at the cytoskeletal and cell membrane level.
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Affiliation(s)
- N M Maraldi
- Institute of Normal and Pathological Cytomorphology, C.N.R., Laboratory of Cell Biology, IOR, Bologna, Italy.
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34
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Mercier PA, Winegarden NA, Westwood JT. Human heat shock factor 1 is predominantly a nuclear protein before and after heat stress. J Cell Sci 1999; 112 ( Pt 16):2765-74. [PMID: 10413683 DOI: 10.1242/jcs.112.16.2765] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The induction of the heat shock genes in eukaryotes by heat and other forms of stress is mediated by a transcription factor known as heat shock factor 1 (HSF1). HSF1 is present in unstressed metazoan cells as a monomer with low affinity for DNA, and upon exposure to stress it is converted to an ‘active’ homotrimer that binds the promoters of heat shock genes with high affinity and induces their transcription. The conversion of HSF1 to its active form is hypothesized to be a multistep process involving physical changes in the HSF1 molecule and the possible translocation of HSF1 from the cytoplasm to the nucleus. While all studies to date have found active HSF1 to be a nuclear protein, there have been conflicting reports on whether the inactive form of HSF is predominantly a cytoplasmic or nuclear protein. In this study, we have made antibodies against human HSF1 and have reexamined its localization in unstressed and heat-shocked human HeLa and A549 cells, and in green monkey Vero cells. Biochemical fractionation of heat-shocked HeLa cells followed by western blot analysis showed that HSF1 was mostly found in the nuclear fraction. In extracts made from unshocked cells, HSF1 was predominantly found in the cytoplasmic fraction using one fractionation procedure, but was distributed approximately equally between the cytoplasmic and nuclear fractions when a different procedure was used. Immunofluorescence microscopy revealed that HSF1 was predominantly a nuclear protein in both heat shocked and unstressed cells. Quantification of HSF1 staining showed that approximately 80% of HSF1 was present in the nucleus both before and after heat stress. These results suggest that HSF1 is predominantly a nuclear protein prior to being exposed to stress, but has low affinity for the nucleus and is easily extracted using most biochemical fractionation procedures. These results also imply that HSF1 translocation is probably not part of the multistep process in HSF1 activation for many cell types.
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Affiliation(s)
- P A Mercier
- Department of Zoology, University of Toronto, Mississauga, Ontario, Canada L5L 1C6
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35
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Bell P, Scheer U. Developmental changes in RNA polymerase I and TATA box-binding protein during early Xenopus embryogenesis. Exp Cell Res 1999; 248:122-35. [PMID: 10094820 DOI: 10.1006/excr.1999.4411] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Xenopus early embryos are transcriptionally quiescent until the midblastula transition (MBT). We have examined the question of whether the absence of rRNA synthesis is related to a deficiency in the RNA polymerase I (pol I) transcription machinery. Previously we have demonstrated that the maternally provided pol I transcription factor UBF already binds to the inactive rRNA genes of pre-MBT embryos (P. Bell et al., 1997, J. Cell Sci. 110, 2053-2063). Here we have analyzed the fate of pol I and the TATA box-binding protein (TBP) through immunofluorescence and immunoblotting experiments. Pol I stockpiled in the egg is taken up by in vitro assembled pronuclei and concentrated into numerous distinct nuclear domains. Comparable storage sites of template-free pol I are also seen in nuclei of blastula to neurula stage embryos. In contrast, the amount of TBP is relatively low in oocytes and eggs but increases dramatically during the cleavage stages. Most of the newly synthesized TBP colocalizes with the stored form of pol I in the extranucleolar domains of blastula/gastrula embryos. The amount of TBP per embryo reaches peak values at the blastula/gastrula stage and then rapidly declines to normal somatic levels. The positive correlation of maximal TBP levels with the timing of the MBT suggests that overproduction of TBP is required for the formation of productive transcription complexes.
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Affiliation(s)
- P Bell
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Am Hubland, Würzburg, D-97074, Germany
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36
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Lee Y, Lloyd AM, Roux SJ. Antisense expression of the CK2 alpha-subunit gene in Arabidopsis. Effects on light-regulated gene expression and plant growth. PLANT PHYSIOLOGY 1999; 119:989-1000. [PMID: 10069836 PMCID: PMC32112 DOI: 10.1104/pp.119.3.989] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/1998] [Accepted: 11/21/1998] [Indexed: 05/17/2023]
Abstract
The protein kinase CK2 (formerly casein kinase II) is thought to be involved in light-regulated gene expression in plants because of its ability to phosphorylate transcription factors that bind to the promoter regions of light-regulated genes in vitro. To address this possibility in vivo and to learn more about the potential physiological roles of CK2 in plants, we transformed Arabidopsis with an antisense construct of the CK2 alpha-subunit gene and investigated both morphological and molecular phenotypes. Antisense transformants had a smaller adult leaf size and showed increased expression of chs in darkness and of cab and rbcS after red-light treatment. The latter molecular phenotype implied that CK2 might serve as one of several negative and quantitative effectors in light-regulated gene expression. The possible mechanism of CK2 action and its involvement in the phytochrome signal transduction pathway are discussed.
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MESH Headings
- Arabidopsis/enzymology
- Arabidopsis/genetics
- Arabidopsis/growth & development
- Base Sequence
- CDC2 Protein Kinase/genetics
- CDC2 Protein Kinase/metabolism
- Casein Kinase II
- DNA, Antisense/genetics
- Gene Expression Regulation, Enzymologic/radiation effects
- Gene Expression Regulation, Plant/radiation effects
- Genes, Plant
- Light
- Plant Leaves/growth & development
- Plants, Genetically Modified
- Protein Serine-Threonine Kinases/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Transformation, Genetic
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Affiliation(s)
- Y Lee
- Department of Botany and Institute for Cellular and Molecular Biology, The University of Texas, Austin, Texas 78713, USA
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37
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Orford RL, Robinson C, Haydon JM, Patient RK, Guille MJ. The maternal CCAAT box transcription factor which controls GATA-2 expression is novel and developmentally regulated and contains a double-stranded-RNA-binding subunit. Mol Cell Biol 1998; 18:5557-66. [PMID: 9710639 PMCID: PMC109140 DOI: 10.1128/mcb.18.9.5557] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/1998] [Accepted: 06/10/1998] [Indexed: 11/20/2022] Open
Abstract
The transcription factor GATA-2 is expressed at high levels in the nonneural ectoderm of the Xenopus embryo at neurula stages, with lower amounts of RNA present in the ventral mesoderm and endoderm. The promoter of the GATA-2 gene contains an inverted CCAAT box conserved among Xenopus laevis, humans, chickens, and mice. We have shown that this sequence is essential for GATA-2 transcription during early development and that the factor binding it is maternal. The DNA-binding activity of this factor is detectable in nuclei and chromatin bound only when zygotic GATA-2 transcription starts. Here we report the characterization of this factor, which we call CBTF (CCAAT box transcription factor). CBTF activity mainly appears late in oogenesis, when it is nuclear, and the complex has multiple subunits. We have identified one subunit of the factor as p122, a Xenopus double-stranded-RNA-binding protein. The p122 protein is perinuclear during early embryonic development but moves from the cytoplasm into the nuclei of embryonic cells at stage 9, prior to the detection of CBTF activity in the nucleus. Thus, the accumulation of CBTF activity in the nucleus is a multistep process. We show that the p122 protein is expressed mainly in the ectoderm. Expression of p122 mRNA is more restricted, mainly to the anterior ectoderm and mesoderm and to the neural tube. Two properties of CBTF, its dual role and its cytoplasm-to-nucleus translocation, are shared with other vertebrate maternal transcription factors and may be general properties of these proteins.
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Affiliation(s)
- R L Orford
- Biophysics Laboratories, Division of Molecular and Cell Biology, Institute of Biomolecular and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DY, United Kingdom
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38
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Jiang YW, Veschambre P, Erdjument-Bromage H, Tempst P, Conaway JW, Conaway RC, Kornberg RD. Mammalian mediator of transcriptional regulation and its possible role as an end-point of signal transduction pathways. Proc Natl Acad Sci U S A 1998; 95:8538-43. [PMID: 9671713 PMCID: PMC21111 DOI: 10.1073/pnas.95.15.8538] [Citation(s) in RCA: 252] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A multiprotein complex isolated from murine cells is identified as a counterpart of the yeast Mediator of transcriptional regulation on the basis of the following: homologs of two subunits of yeast Mediator, Srb7 and Med7, copurify with the complex; peptide sequencing reveals, in addition, homologs of the yeast Mediator subunits Rgr1 and Med6; as with yeast Mediator, the mouse complex binds to the RNA polymerase II C-terminal domain (CTD) and stimulates phosphorylation of the CTD by TFIIH. Peptide sequencing also identifies a component of mouse Mediator as a relative of Ring-3 protein, a mitogen-activated nuclear protein kinase, raising the possibility of Mediator as an end point of signal transduction pathways.
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Affiliation(s)
- Y W Jiang
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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39
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Topilko P, Levi G, Merlo G, Mantero S, Desmarquet C, Mancardi G, Charnay P. Differential regulation of the zinc finger genes Krox-20 and Krox-24 (Egr-1) suggests antagonistic roles in Schwann cells. J Neurosci Res 1997; 50:702-12. [PMID: 9418958 DOI: 10.1002/(sici)1097-4547(19971201)50:5<702::aid-jnr7>3.0.co;2-l] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Krox-20 and Krox-24 (Egr-1) encode closely related zinc finger transcription factors, which interact with the same DNA target sequences. Krox-20 is required for myelination in the peripheral nervous system. Using lacZ knock-in mutant mouse lines as well as immunohistochemical analyses, we have studied the expression of Krox-20 and Krox-24 in the Schwann cell lineage during normal development and following nerve lesion in the mouse and in human neuropathies. During embryogenesis, the two genes are expressed in a successive and mutually exclusive manner, Krox-24 being restricted to Schwann cell precursors and Krox-20 to mature Schwann cells. At birth, Krox-24 is reactivated and the two genes are coexpressed. In the adult, Krox-20 is expressed in myelinating cells, while Krox-24 is restricted to nonmyelinating cells. Following nerve lesion, Krox-24 is strongly induced in Schwann cells, reinforcing the link between its expression and the nonmyelinating and/or proliferative state, whereas Krox-20 is downregulated. These data are consistent with Krox-20 and Krox-24 playing antagonistic roles during the development of the Schwann cell lineage. In particular, their balance of expression might participate in the choice between myelinating and nonmyelinating pathways.
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Affiliation(s)
- P Topilko
- Unité 368 de l'Institut National de la Santé et de la Recherche Médicale, Ecole Normale Supérieure, Paris, France
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40
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Yang Y, Yang Y, Smith HC. Multiple protein domains determine the cell type-specific nuclear distribution of the catalytic subunit required for apolipoprotein B mRNA editing. Proc Natl Acad Sci U S A 1997; 94:13075-80. [PMID: 9371802 PMCID: PMC24265 DOI: 10.1073/pnas.94.24.13075] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/1997] [Accepted: 10/03/1997] [Indexed: 02/05/2023] Open
Abstract
Apolipoprotein B (apoB) mRNA editing catalyzed by apoB mRNA editing catalytic subunit 1 (APOBEC-1) has been proposed to be a nuclear process. To test this hypothesis, the subcellular distribution of hemagglutinin- (HA) tagged APOBEC-1 expressed in transiently transfected hepatoma cells was determined by indirect immunofluorescence microscopy. HA-APOBEC-1 was detected in both the nucleus and cytoplasm of rat and human hepatoma cells. Mutagenesis of APOBEC-1 demonstrated that the N-terminal 56 amino acids (1-56) were necessary for the nuclear distribution of APOBEC-1, but this region did not contain a functional nuclear localization signal (NLS). However, we identified a 24-amino acid domain in the C terminus of APOBEC-1 with characteristics of a cytoplasmic retention signal (CRS) or a nuclear export signal (NES). These data suggest, therefore, that the nuclear import of APOBEC-1 may not be mediated by a positive NLS; rather, it may be achieved by overcoming the effect of a CRS/NES. We also demonstrated that the nuclear distribution of APOBEC-1 occurred only in cell lines that were capable of editing apoB RNA. We propose that the cellular distribution of APOBEC-1 is determined by multiple domains within this protein, and a nuclear localization of the enzyme may be regulated by cell type-specific factors that render these cells uniquely editing competent.
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Affiliation(s)
- Y Yang
- Department of Biochemistry, University of Rochester, NY 14642, USA
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41
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Koike K, Uchiumi T, Ohga T, Toh S, Wada M, Kohno K, Kuwano M. Nuclear translocation of the Y-box binding protein by ultraviolet irradiation. FEBS Lett 1997; 417:390-4. [PMID: 9409758 DOI: 10.1016/s0014-5793(97)01296-9] [Citation(s) in RCA: 156] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Y-box binding protein, YB-1, is a member of a DNA binding protein family with a structurally and functionally conserved cold shock domain. Using Western blotting and immunohistochemical methods, larger amounts of YB-1 were detected in the cytosol, particularly at the perinuclear region, than in the nucleus of human cancer cells. UV irradiation increased accumulation of YB-1 in the nucleus at 20 min and thereafter. This translocation of YB-1 into the nucleus by UV irradiation was blocked by the protein kinase inhibitor H-7, but not HA-1004. Both green fluorescent protein (GFP)-YB-1 and GFP-YB-1C with the C-terminus (248-317) of YB-1 were located mainly in the cytosol, but GFP-YB-1deltaC with a deletion at the C-terminus of YB-1 was located in the nucleus. YB-1 is translocated into the nucleus by UV irradiation, possibly through a protein kinase C-mediated signal transduction pathway, and the C-terminal region of YB-1 might be important for cytoplasmic retention of YB-1.
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Affiliation(s)
- K Koike
- Department of Biochemistry, Kyushu University School of Medicine, Fukuoka, Japan.
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Andreoli JM, Jang SI, Chung E, Coticchia CM, Steinert PM, Markova NG. The expression of a novel, epithelium-specific ets transcription factor is restricted to the most differentiated layers in the epidermis. Nucleic Acids Res 1997; 25:4287-95. [PMID: 9336459 PMCID: PMC147045 DOI: 10.1093/nar/25.21.4287] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Ets proteins have been implicated in the regulation of gene expression during a variety of biological processes, including growth control, differentiation, development and transformation. More than 35 related proteins containing the 'ets domain' have now been found which specifically interact with DNA sequences encompassing the core tetranucleotide GGAA. Although ets responsive genes have been identified in the epidermis, little is known about their distribution and function in this tissue. We have now demonstrated that epidermis and cultured epidermal keratinocytes synthesize numerous ets proteins. The expression of some of these proteins is regulated as a function of differentiation. Among these is a novel ets transcription factor with a dual DNA-binding specificity, which we have called jen. The expression of jen is not only epithelial specific, but it is the only ets protein so far described, and one of the very few transcription factors whose expression is restricted to the most differentiated epidermal layers. We show that two epidermal marker genes whose expression coincides with that of jen are transregulated by this protein in a complex mode which involves interactions with other transcriptional regulators such as Sp1 and AP1.
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Affiliation(s)
- J M Andreoli
- Laboratory of Skin Biology, NIAMS, NIH, Bethesda, MD 20892-2752, USA
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43
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Winge DR. Copper-regulatory domain involved in gene expression. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1997; 58:165-95. [PMID: 9308366 DOI: 10.1016/s0079-6603(08)60036-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Copper ion homeostasis in yeast is maintained through regulated expression of genes involved in copper ion uptake, Cu(I) sequestration, and defense against reactive oxygen intermediates. Positive and negative copper ion regulation is observed, and both effects are mediated by Cu(I)-sensing transcription factors. The mechanism of Cu(I) regulation is distinct for transcriptional activation versus transcriptional repression. Cu(I) activation of gene expression in S. cerevisiae and C. glabrata occurs through Cu-regulated DNA binding. The activation process involves Cu(I) cluster formation within the regulatory domain in Ace1 and Amt1. Cu(I) binding stabilizes a specific conformation capable of high-affinity interaction with specific DNA promoter sequences. Cu(I)-activated transcription factors are modular proteins in which the DNA-binding domain is distinct from the domain that mediates transcriptional activation. The all-or-nothing formation of the polycopper cluster permits a graded response of the cell to environmental copper. Cu(I) triggering may involve a metal exchange reaction converting Ace1 from a Zn(II)-specific conformer to a clustered Cu(I) conformer. The Cu(I) regulatory domain occurs in transcription factors from S. cerevisiae and C. glabrata. Sequence homologs are also known in Y. lipolytica and S. pombe, although no functional information is available for these candidate regulatory molecules. The presence of the Cu(I) regulatory domain in four distinct yeast strains suggests that this Cu-responsive domain may occur in other eukaryotes. Cu-mediated repression of gene expression in S. cerevisiae occurs through Cu(I) regulation of Mac1. Cu(I) binding to Mac1 appears to inhibit the transactivation domain. The Cu(I) specificity of this repression is likely to arise from formation of a polycopper thiolate cluster.
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Affiliation(s)
- D R Winge
- Department of Medicine, University of Utah Health Sciences Center, Salt Lake City 84132, USA
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44
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Abstract
Xenopus nuclear factor 7 (xnf7) is a maternally expressed nuclear protein that is retained in the cytoplasm from oocyte maturation until the midblastula transition (MBT). Mutations of the xnf7 phosphorylation sites to glutamic acids (dnxnf7) resulted in the retention of the endogenous protein in the cytoplasm past the MBT, indicating that cytoplasmic retention is a phosphorylation dependent process. In addition, dnxnf7 acted as a dominant negative mutant by keeping the endogenous xnf7 protein in the cytoplasm past the MBT. Overexpression of dnxnf7 in future dorsal blastomeres resulted in a ventralized or posteriorized phenotype in which the embryos lacked anterior structures, while overexpression in ventral blastomeres resulted in dorsalized embryos. dnxnf7 also affected the expression of both dorsal and ventral mesodermal markers. These data suggest that xnf7 functions in dorsal/ventral patterning and that the movement of the protein from the cytoplasm to the nucleus at the MBT is critical for the execution of a genetic program conferring a dorsal or ventral identity to the mesoderm.
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Affiliation(s)
- H M El-Hodiri
- Department of Molecular Genetics, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA
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45
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Abstract
Growth of the rae1-1 mutant of Schizosaccharomyces pombe at restrictive temperature results in accumulation of poly(A)+ RNA in the nucleus and a cell cycle arrest at the G2/M boundary. We demonstrate here that rae1 function is required for a process other than mRNA export which is essential for advancement through mitosis. Cells lacking rae1 function arrest with elevated Cdc2p kinase levels at a step before the formation of a mitotic spindle and without separation of the spindle pole bodies. Rae1p was localized to the nuclear periphery, consistent with a role in nucleocytoplasmic trafficking, which could include protein import. We propose a model where rae1 functions in cell cycle progression through trafficking of proteins required for mitosis.
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Affiliation(s)
- W A Whalen
- Laboratory of Molecular Virology, National Cancer Institute, Bethesda, MD 20892, USA
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46
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El-Hodiri HM, Che S, Nelman-Gonzalez M, Kuang J, Etkin LD. Mitogen-activated protein kinase and cyclin B/Cdc2 phosphorylate Xenopus nuclear factor 7 (xnf7) in extracts from mature oocytes. Implications for regulation of xnf7 subcellular localization. J Biol Chem 1997; 272:20463-70. [PMID: 9252356 DOI: 10.1074/jbc.272.33.20463] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Xenopus nuclear factor 7 (xnf7) is a maternally expressed putative transcription factor that exhibits phosphorylation-dependent changes in subcellular localization during early Xenopus development. Xnf7 is localized to the germinal vesicle (nucleus) of immature oocytes in a hypophosphorylated state. Xnf7 is phosphorylated during oocyte maturation and released to the cytoplasm. The protein is retained in the cytoplasm during early embryonic cleavage stages but returns to nuclei at the mid-blastula transition. Xnf7 is phosphorylated at two sites during oocyte maturation, designated P1, consisting of one threonine at position 103, and P2, consisting of three clustered threonines at positions 209, 212, and 218. Phosphorylation of both sites is important in regulating xnf7 localization. The P1 site can be phosphorylated by cyclin B/Cdc2 in vitro. To further understand the mechanisms regulating subcellular localization of xnf7 during early development, kinases capable of catalyzing phosphorylation of the P2 site were purified from mature oocyte extracts. We found that mitogen-activated protein kinase phosphorylated Thr212 and cyclin B/Cdc2 phosphorylated Thr 209 and Thr212. No other kinase in mature oocyte extracts phosphorylated the xnf7 P2 site to a significant extent. These results implicate mitogen-activated protein kinase and cyclin B/Cdc2 in regulating xnf7 localization during oocyte maturation. This also suggests that localization of xnf7 may be regulated by multiple kinase activation pathways.
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Affiliation(s)
- H M El-Hodiri
- Department of Molecular Genetics, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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47
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Kumar AS, Venkatesh VC, Planer BC, Feinstein SI, Ballard PL. Phorbol ester down-regulation of lung surfactant protein B gene expression by cytoplasmic trapping of thyroid transcription factor-1 and hepatocyte nuclear factor 3. J Biol Chem 1997; 272:20764-73. [PMID: 9252399 DOI: 10.1074/jbc.272.33.20764] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The lung-specific surfactant protein B (SP-B) is essential for surfactant function and normal respiration. We investigated the role of thyroid transcription factor-1 (TTF-1) and hepatocyte nuclear factor 3 (HNF3) in the down-regulation of SP-B gene expression by phorbol ester in pulmonary adenocarcinoma H441 cells. Responsiveness to 12-O-tetradecanoylphorbol-13-acetate (TPA) localized to the SP-B proximal promoter (-140/-65 bp) and specifically to binding sites for TTF-1 and HNF3, which act as cell-specific enhancers of SP-B expression. Treatment of cells with TPA (10 nM) caused a time-dependent decrease in both TTF-1 and HNF3 in nuclear extracts and accumulation of both factors in the cytoplasm as assessed by electromobility shift, Western, Southwestern, and immunofluorescence assays. Treatment did not alter the mRNA content or DNA binding activity for either transcription factor. We conclude that down-regulation of SP-B gene expression by phorbol ester involves cytoplasmic trapping and loss of TTF-1 and HNF3 from the nucleus. This mechanism of action is independent of AP-1 and other transcription factors known to be influenced by phorbol ester.
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Affiliation(s)
- A S Kumar
- University of Pennsylvania School of Medicine, Institute for Environmental Medicine, Philadelphia, Pennsylvania 19104-6068, USA
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48
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Abstract
The interaction of proteins with DNA is a central theme of molecular biology. In this article, we review some of the principal techniques currently used for the identification and characterization of DNA binding proteins, and for investigation of the molecular interactions that are responsible for the recognition of specific DNA sequences.
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Affiliation(s)
- M J Guille
- Division of Molecular and Cell Biology, School of Biological Science, University of Portsmouth, UK
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Ghoshroy S, Lartey R, Sheng J, Citovsky V. TRANSPORT OF PROTEINS AND NUCLEIC ACIDS THROUGH PLASMODESMATA. ACTA ACUST UNITED AC 1997; 48:27-50. [PMID: 15012255 DOI: 10.1146/annurev.arplant.48.1.27] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite a potentially key role in cell-to-cell communication, plant intercellular connections-the plasmodesmata-have long been a biological "black box." Little is known about their protein composition, regulatory mechanisms, or transport pathways. However, recent studies have shed some light on plasmodesmal function. These connections have been shown to actively traffic proteins and protein-nucleic acid complexes between plant cells. This review describes these transport processes-specifically, cell-to-cell movement of plant viruses as well as endogenous cellular proteins-and discusses their possible mechanism(s). For comparison and to provide a broader perspective on the plasmodesmal transport process, the current model for nuclear import, the only other known example of transport of large proteins and protein-nucleic acid complexes through a membrane pore, is summarized. Finally, the function of plasmodesmata as communication boundaries within plant tissue is discussed.
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Affiliation(s)
- Soumitra Ghoshroy
- Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, New York 11794-5215
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50
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Graden JA, Winge DR. Copper-mediated repression of the activation domain in the yeast Mac1p transcription factor. Proc Natl Acad Sci U S A 1997; 94:5550-5. [PMID: 9159110 PMCID: PMC20816 DOI: 10.1073/pnas.94.11.5550] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The expression of a number of genes encoding products involved in copper ion uptake in yeast is specifically inhibited by copper ions. We show here that copper metalloregulation occurs through Cu-dependent repression of the transactivation activity of Mac1p. A segment of the yeast transcription factor Mac1p was identified that activated transcription in vivo in a heterologous system using fusion polypeptides with the yeast Gal4 DNA-binding domain. The Gal4/Mac1p hybrid exhibits transactivation activity that is repressed in cells cultured in the presence of copper salts and derepressed in cells with reduced copper uptake. The repressive effect is specific for copper ions. The concentration dependency of the Cu-inactivation of Gal4/Mac1p is similar to that of Cu-inhibition of CTR1 expression, a known Cu-regulated gene in vivo. Copper inhibition of gene expression is not observed with a Gal4/Mac1p chimera containing the MAC1(up1) substitution within the transactivation domain. Cells harboring the MAC1(up1) allele fail to attenuate FRE1 and CTR1 expression in a Cu-dependent manner. Additional MAC1(up) alleles exist within the first of two cysteine-rich sequence motifs adjacent to the His --> Gln MAC1(up1) encoded substitution. Thus, Cu-regulation of Mac1p function arises from a novel Cu-specific repression of the transactivation domain function. Models for the mechanism of Cu-repression of Mac1p function will be discussed.
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Affiliation(s)
- J A Graden
- University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA
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