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Marquardt S, Petrillo E, Manavella PA. Cotranscriptional RNA processing and modification in plants. THE PLANT CELL 2023; 35:1654-1670. [PMID: 36259932 PMCID: PMC10226594 DOI: 10.1093/plcell/koac309] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/14/2022] [Indexed: 05/30/2023]
Abstract
The activities of RNA polymerases shape the epigenetic landscape of genomes with profound consequences for genome integrity and gene expression. A fundamental event during the regulation of eukaryotic gene expression is the coordination between transcription and RNA processing. Most primary RNAs mature through various RNA processing and modification events to become fully functional. While pioneering results positioned RNA maturation steps after transcription ends, the coupling between the maturation of diverse RNA species and their transcription is becoming increasingly evident in plants. In this review, we discuss recent advances in our understanding of the crosstalk between RNA Polymerase II, IV, and V transcription and nascent RNA processing of both coding and noncoding RNAs.
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Affiliation(s)
- Sebastian Marquardt
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Ezequiel Petrillo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET-UBA), Buenos Aires, C1428EHA, Argentina
| | - Pablo A Manavella
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe 3000, Argentina
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2
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Fukudome A, Ishiga Y, Nagashima Y, Davidson KH, Chou HA, Mysore KS, Koiwa H. Functional diversity of Medicago truncatula RNA polymerase II CTD phosphatase isoforms produced in the Arabidopsis thaliana superexpression platform. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 321:111309. [PMID: 35696909 DOI: 10.1016/j.plantsci.2022.111309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 04/25/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
Medicago truncatula is a model system for legume plants, which has substantially expanded the genome relative to the prototypical model dicot plant, Arabidopsis thaliana. An essential transcriptional regulator, FCP1 (transcription factor IIF-interacting RNA polymerase II carboxyl-terminal phosphatase 1) ortholog, is encoded by a single essential gene CPL4 (CTD-phosphatase-like 4), whereas M. truncatula genome contains four genes homologous to FCP1/AtCPL4, and splicing variants of MtCPL4 are observed. Functional diversification of MtCPL4 family proteins was analyzed using recombinant proteins (MtCPL4a1, MtCPL4a2, and MtCPL4b) produced in Arabidopsis cell culture system developed for plant protein overexpression. In vitro CTD phosphatase assay using highly purified MtCPL4 preparations revealed a potent CTD phosphatase activity in MtCPL4b, but not two splicing variants of MtCPL4a. On the other hand, in planta binding assay to RNA polymerase II (pol II) revealed a greater pol II-binding activity of both MtCPL4a variants. Our results indicate functional diversification of MtCPL4 isoforms and suggest the presence of a large number of functionally specialized CTD-phosphatase-like proteins in plants.
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Affiliation(s)
- Akihito Fukudome
- Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Yasuhiro Ishiga
- Noble Research Institute, LLC., Ardmore, OK 73401, USA; Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yukihiro Nagashima
- Vegetable and Fruit Development Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Katherine H Davidson
- Vegetable and Fruit Development Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Hsiu-An Chou
- Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Kirankumar S Mysore
- Noble Research Institute, LLC., Ardmore, OK 73401, USA; Institute for Agricultural Biosciences, Oklahoma State University, Ardmore, Oklahoma 73401, USA; Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma 74044, USA
| | - Hisashi Koiwa
- Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX 77843, USA; Vegetable and Fruit Development Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA.
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3
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Fukudome A, Aksoy E, Wu X, Kumar K, Jeong IS, May K, Russell WK, Koiwa H. Arabidopsis CPL4 is an essential C-terminal domain phosphatase that suppresses xenobiotic stress responses. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:27-39. [PMID: 25041272 DOI: 10.1111/tpj.12612] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 06/27/2014] [Accepted: 07/02/2014] [Indexed: 05/20/2023]
Abstract
Eukaryotic gene expression is both promoted and inhibited by the reversible phosphorylation of the C-terminal domain of RNA polymerase II (pol II CTD). More than 20 Arabidopsis genes encode CTD phosphatase homologs, including four CTD phosphatase-like (CPL) family members. Although in vitro CTD phosphatase activity has been established for some CPLs, none have been shown to be involved in the phosphoregulation of pol II in vivo. Here we report that CPL4 is a CTD phosphatase essential for the viability of Arabidopsis thaliana. Mass spectrometry analysis identified the pol II subunits RPB1, RPB2 and RPB3 in the affinity-purified CPL4 complex. CPL4 dephosphorylates both Ser2- and Ser5-PO(4) of the CTD in vitro, with a preference for Ser2-PO(4). Arabidopsis plants overexpressing CPL4 accumulated hypophosphorylated pol II, whereas RNA interference-mediated silencing of CPL4 promoted hyperphosphorylation of pol II. A D128A mutation in the conserved DXDXT motif of the CPL4 catalytic domain resulted in a dominant negative form of CPL4, the overexpression of which inhibited transgene expression in transient assays. Inhibition was abolished by truncation of the phosphoprotein-binding Breast Cancer 1 C-terminal domain of CPL4, suggesting that both catalytic function and protein-protein interaction are essential for CPL4-mediated regulation of gene expression. We were unable to recover a homozygous cpl4 mutant, probably due to the zygotic lethality of this mutation. The reduction in CPL4 levels in CPL4(RNAi) plants increased transcript levels of a suite of herbicide/xenobiotic-responsive genes and improved herbicide tolerance, thus suggesting an additional role for CPL4 as a negative regulator of the xenobiotic detoxification pathway.
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Affiliation(s)
- Akihito Fukudome
- Molecular and Environmental Plant Sciences, Department of Horticultural Sciences, Vegetable and Fruit Development Center, Texas A&M University, College Station, TX, 77843, USA
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4
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Regulation of abiotic stress signalling by Arabidopsis C-terminal domain phosphatase-like 1 requires interaction with a k-homology domain-containing protein. PLoS One 2013; 8:e80509. [PMID: 24303021 PMCID: PMC3841200 DOI: 10.1371/journal.pone.0080509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 10/03/2013] [Indexed: 11/26/2022] Open
Abstract
Arabidopsis thaliana CARBOXYL-TERMINAL DOMAIN (CTD) PHOSPHATASE-LIKE 1 (CPL1) regulates plant transcriptional responses to diverse stress signals. Unlike typical CTD phosphatases, CPL1 contains two double-stranded (ds) RNA binding motifs (dsRBMs) at its C-terminus. Some dsRBMs can bind to dsRNA and/or other proteins, but the function of the CPL1 dsRBMs has remained obscure. Here, we report identification of REGULATOR OF CBF GENE EXPRESSION 3 (RCF3) as a CPL1-interacting protein. RCF3 co-purified with tandem-affinity-tagged CPL1 from cultured Arabidopsis cells and contains multiple K-homology (KH) domains, which were predicted to be important for binding to single-stranded DNA/RNA. Yeast two-hybrid, luciferase complementation imaging, and bimolecular fluorescence complementation analyses established that CPL1 and RCF3 strongly associate in vivo, an interaction mediated by the dsRBM1 of CPL1 and the KH3/KH4 domains of RCF3. Mapping of functional regions of CPL1 indicated that CPL1 in vivo function requires the dsRBM1, catalytic activity, and nuclear targeting of CPL1. Gene expression profiles of rcf3 and cpl1 mutants were similar during iron deficiency, but were distinct during the cold response. These results suggest that tethering CPL1 to RCF3 via dsRBM1 is part of the mechanism that confers specificity to CPL1-mediated transcriptional regulation.
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Barbazuk WB, Fu Y, McGinnis KM. Genome-wide analyses of alternative splicing in plants: opportunities and challenges. Genome Res 2008; 18:1381-92. [PMID: 18669480 DOI: 10.1101/gr.053678.106] [Citation(s) in RCA: 254] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Alternative splicing (AS) creates multiple mRNA transcripts from a single gene. While AS is known to contribute to gene regulation and proteome diversity in animals, the study of its importance in plants is in its early stages. However, recently available plant genome and transcript sequence data sets are enabling a global analysis of AS in many plant species. Results of genome analysis have revealed differences between animals and plants in the frequency of alternative splicing. The proportion of plant genes that have one or more alternative transcript isoforms is approximately 20%, indicating that AS in plants is not rare, although this rate is approximately one-third of that observed in human. The majority of plant AS events have not been functionally characterized, but evidence suggests that AS participates in important plant functions, including stress response, and may impact domestication and trait selection. The increasing availability of plant genome sequence data will enable larger comparative analyses that will identify functionally important plant AS events based on their evolutionary conservation, determine the influence of genome duplication on the evolution of AS, and discover plant-specific cis-elements that regulate AS. This review summarizes recent analyses of AS in plants, discusses the importance of further analysis, and suggests directions for future efforts.
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Affiliation(s)
- W Brad Barbazuk
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA.
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Tamada Y, Nakamori K, Nakatani H, Matsuda K, Hata S, Furumoto T, Izui K. Temporary expression of the TAF10 gene and its requirement for normal development of Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2007; 48:134-46. [PMID: 17148695 DOI: 10.1093/pcp/pcl048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
TAF10 is one of the TATA box-binding protein (TBP)-associated factors (TAFs) which constitute a TFIID with a TBP. Initially most TAFs were thought to be necessary for accurate transcription initiation from a broad group of core promoters. However, it was recently revealed that several TAFs are expressed in limited tissues during animal embryogenesis, and are indispensable for normal development of the tissues. They are called 'selective' TAFs. In plants, however, little is known as to these 'selective' TAFs and their function. Here we isolated the Arabidopsis thaliana TAF10 gene (atTAF10), which is a single gene closely related to the TAF10 genes of other organisms. atTAF10 was expressed transiently during the development of several organs such as lateral roots, rosette leaves and most floral organs. Such an expression pattern was clearly distinct from that of Arabidopsis Rpb1, which encodes a component of RNA polymerase II, suggesting that atTAF10 functions in not only general transcription but also the selective expression of a subset of genes. In a knockdown mutant of atTAF10, we observed several abnormal phenotypes involved in meristem activity and leaf development, suggesting that atTAF10 is concerned in pleiotropic, but selected morphological events in Arabidopsis. These results clearly demonstrate that TAF10 is a 'selective' TAF in plants, providing a new insight into the function of TAFs in plants.
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Affiliation(s)
- Yosuke Tamada
- Laboratory of Plant Physiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan
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7
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Pintér M, Lent DD, Strausfeld NJ. Memory consolidation and gene expression in Periplaneta americana. Learn Mem 2005; 12:30-8. [PMID: 15647592 PMCID: PMC548493 DOI: 10.1101/lm.87905] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A unique behavioral paradigm has been developed for Periplaneta americana that assesses the timing and success of memory consolidation leading to long-term memory of visual-olfactory associations. The brains of trained and control animals, removed at the critical consolidation period, were screened by two-directional suppression subtractive hybridization. Screens identified neurobiologically relevant as well as novel genes that are differentially expressed at the consolidation phase of memory. The differential expression of six transcripts was confirmed with real-time RT-PCR experiments. There are mitochondrial DNA encoded transcripts among the up-regulated ones (COX, ATPase6). One of the confirmed down-regulated transcripts is RNA polymerase II largest subunit. The mitochondrial genes are of particular interest because mitochondria represent autonomous DNA at synapses. These transcripts will be used as one of several tools in the identification of neuronal circuits, such as in the mushroom bodies, that are implicated in memory consolidation.
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Affiliation(s)
- Marianna Pintér
- Arizona Research Laboratories, Division of Neurobiology, The University of Arizona, Tucson, Arizona 85721, USA.
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8
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Wang W, Chen X. HUA ENHANCER3 reveals a role for a cyclin-dependent protein kinase in the specification of floral organ identity in Arabidopsis. Development 2004; 131:3147-56. [PMID: 15175247 PMCID: PMC5142244 DOI: 10.1242/dev.01187] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In plants, organs are generated post-embryonically from highly organized structures known as meristems. Cell division in the meristem is closely integrated with cell fate specification and organ formation. The presence of multiple cyclin-dependent kinases (CDKs) and their partner cyclins in plants and other multicellular organisms probably reflects the complexity of cell cycle regulation within developmental contexts. The Arabidopsis genome encodes at least eight CDKs and 30 cyclins. However, no mutants in any CDKs have been reported, and the function of the great majority of these genes in plant development is unknown. We show that HUA ENHANCER3 (HEN3), which encodes CDKE, a homolog of mammalian CDK8, is required for the specification of stamen and carpel identities and for the proper termination of stem cells in the floral meristem. Therefore, CDK8 plays a role in cell differentiation in a multicellular organism.
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9
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Koiwa H, Barb AW, Xiong L, Li F, McCully MG, Lee BH, Sokolchik I, Zhu J, Gong Z, Reddy M, Sharkhuu A, Manabe Y, Yokoi S, Zhu JK, Bressan RA, Hasegawa PM. C-terminal domain phosphatase-like family members (AtCPLs) differentially regulate Arabidopsis thaliana abiotic stress signaling, growth, and development. Proc Natl Acad Sci U S A 2002; 99:10893-8. [PMID: 12149434 PMCID: PMC125069 DOI: 10.1073/pnas.112276199] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cold, hyperosmolarity, and abscisic acid (ABA) signaling induce RD29A expression, which is an indicator of the plant stress adaptation response. Two nonallelic Arabidopsis thaliana (ecotype C24) T-DNA insertional mutations, cpl1 and cpl3, were identified based on hyperinduction of RD29A expression that was monitored by using the luciferase (LUC) reporter gene (RD29ALUC) imaging system. Genetic linkage analysis and complementation data established that the recessive cpl1 and cpl3 mutations are caused by T-DNA insertions in AtCPL1 (Arabidopsis C-terminal domain phosphatase-like) and AtCPL3, respectively. Gel assays using recombinant AtCPL1 and AtCPL3 detected innate phosphatase activity like other members of the phylogenetically conserved family that dephosphorylate the C-terminal domain of RNA polymerase II (RNAP II). cpl1 mutation causes RD29ALUC hyperexpression and transcript accumulation in response to cold, ABA, and NaCl treatments, whereas the cpl3 mutation mediates hyperresponsiveness only to ABA. Northern analysis confirmed that LUC transcript accumulation also occurs in response to these stimuli. cpl1 plants accumulate biomass more rapidly and exhibit delayed flowering relative to wild type whereas cpl3 plants grow more slowly and flower earlier than wild-type plants. Hence AtCPL1 and AtCPL3 are negative regulators of stress responsive gene transcription and modulators of growth and development. These results suggest that C-terminal domain phosphatase regulation of RNAP II phosphorylation status is a focal control point of complex processes like plant stress responses and development. AtCPL family members apparently have both unique and overlapping transcriptional regulatory functions that differentiate the signal output that determines the plant response.
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Affiliation(s)
- Hisashi Koiwa
- Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, IN 47907-1165, USA
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10
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Oxelman B, Bremer B. Discovery of paralogous nuclear gene sequences coding for the second-largest subunit of RNA polymerase II (RPB2) and their phylogenetic utility in gentianales of the asterids. Mol Biol Evol 2000; 17:1131-45. [PMID: 10908634 DOI: 10.1093/oxfordjournals.molbev.a026396] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Paralogous sequences of the RPB2 gene are demonstrated in the angiosperm order Gentianales. Two different copies were found by using different PCR primer pairs targeting a region that corresponds to exons 22-24 in the Arabidopsis RPB2 gene. One of the copies (RPB2-d) lacks introns in this region, whereas the other has introns at locations corresponding to those of green plants previously investigated. When analyzed with other available RPB2 sequences from this region, all 28 RPB2-d sequences obtained from the Gentianales and the four sequences from the Lamiales form a monophyletic group, together with a previously published tomato cDNA sequence. The substitution patterns, relative rates of change, and nucleotide compositions of the two paralogous RPB2 exon regions are similar, and none of them shows any signs of being a pseudogene. Although multiple copies of similar, paralogous sequences can confound phylogenetic interpretations, the lack of introns in RPB2-d make a priori homology assessment easy. The phylogenetic utility of RPB2-d within the Gentianales is evaluated in comparison with the chloroplast genes ndhF and rbcL. The hierarchical information in the RPB2-d region sequenced is more incongruent with that of the plastid genes than the plastid genes are with each other as determined by incongruence length difference tests. In contrast to the plastid genes, parsimony-informative third codon positions of RPB2 have a significantly higher rate of change than first and second positions. Topologically, the trees from the three genes are similar, and the differences are usually only weakly supported. In terms of support, RPB2 gives the highest jackknife support per sequenced nucleotide, whereas ndhF gives the highest Bremer support per sequenced nucleotide. The RPB2-d locus has the potential to be a valuable nuclear marker for determination of phylogenetic relationships within the euasterid I group of plants.
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Affiliation(s)
- B Oxelman
- Department of Systematic Botany, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
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11
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Larkin RM, Hagen G, Guilfoyle TJ. Arabidopsis thaliana RNA polymerase II subunits related to yeast and human RPB5. Gene X 1999; 231:41-7. [PMID: 10231567 DOI: 10.1016/s0378-1119(99)00090-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Arabidopsis thaliana contains at least four genes that are predicted to encode polypeptides related to the RPB5 subunit found in yeast and human RNA polymerase II. This subunit has been shown to be the largest subunit common to yeast RNA polymerases I, II, and III (RPABC27). More than one of these genes is expressed in Arabidopsis suspension culture cells, but only one of the encoded polypeptides is found in purified RNA polymerases II and III. This polypeptide has a predicted pI of 9.6, matches 14 of 16 amino acids in the amino terminus of cauliflower RPB5 that was microsequenced, and shows 42 and 53% amino acid sequence identity with the yeast and human RPB5 subunits, respectively.
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Affiliation(s)
- R M Larkin
- Department of Biochemistry, 117 Schweitzer Hall, University of Missouri, Columbia, MO 65211, USA
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12
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Sepehri S, Hernandez N. The largest subunit of human RNA polymerase III is closely related to the largest subunit of yeast and trypanosome RNA polymerase III. Genome Res 1997; 7:1006-19. [PMID: 9331371 PMCID: PMC310672 DOI: 10.1101/gr.7.10.1006] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/1997] [Accepted: 08/27/1997] [Indexed: 02/05/2023]
Abstract
In both yeast and mammalian systems, considerable progress has been made toward the characterization of the transcription factors required for transcription by RNA polymerase III. However, whereas in yeast all of the RNA polymerase III subunits have been cloned, relatively little is known about the enzyme itself in higher eukaryotes. For example, no higher eukaryotic sequence corresponding to the largest RNA polymerase III subunit is available. Here we describe the isolation of cDNAs that encode the largest subunit of human RNA polymerase III, as suggested by the observations that (1) antibodies directed against the cloned protein immunoprecipitate an active enzyme whose sensitivity to different concentrations of alpha-amanitin is that expected for human RNA polymerase III; and (2) depletion of transcription extracts with the same antibodies results in inhibition of transcription from an RNA polymerase III, but not from an RNA polymerase II, promoter. Sequence comparisons reveal that regions conserved in the RNA polymerase I, II, and III largest subunits characterized so far are also conserved in the human RNA polymerase III sequence, and thus probably perform similar functions for the human RNA polymerase III enzyme.
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Affiliation(s)
- S Sepehri
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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13
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Stiller JW, Hall BD. The origin of red algae: implications for plastid evolution. Proc Natl Acad Sci U S A 1997; 94:4520-5. [PMID: 9114022 PMCID: PMC20755 DOI: 10.1073/pnas.94.9.4520] [Citation(s) in RCA: 217] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The origin of the red algae has remained an enigma. Historically the Rhodophyta were classified first as plants and later as the most ancient eukaryotic organisms. Recent molecular studies have indicated similarities between red and green plastids, which suggest that there was a single endosymbiotic origin for these organelles in a common ancestor of the rhodophytes and green plants. Previous efforts to confirm or reject this effort by analyses of nuclear DNA have been inconclusive; thus, additional molecular markers are needed to establish the relationship between the host cell lineages, independent of the evolutionary history of their plastids. To furnish such a data set we have sequenced the largest subunit of RNA polymerase II from two red algae, a green alga and a relatively derived amoeboid protist. Phylogenetic analyses provide strong statistical support for an early evolutionary emergence of the Rhodophyta that preceded the origin of the line that led to plants, animals, and fungi. These data, which are congruent with results from extensive analyses of nuclear rDNA, argue for a reexamination of current models of plastid evolution.
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Affiliation(s)
- J W Stiller
- University of Washington, Department of Botany, Box 355325, Seattle, WA 98195, USA
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14
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Simpson GG, Filipowicz W. Splicing of precursors to mRNA in higher plants: mechanism, regulation and sub-nuclear organisation of the spliceosomal machinery. PLANT MOLECULAR BIOLOGY 1996; 32:1-41. [PMID: 8980472 DOI: 10.1007/bf00039375] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The removal of introns from pre-mRNA transcripts and the concomitant ligation of exons is known as pre-mRNA splicing. It is a fundamental aspect of constitutive eukaryotic gene expression and an important level at which gene expression is regulated. The process is governed by multiple cis-acting elements of limited sequence content and particular spatial constraints, and is executed by a dynamic ribonucleoprotein complex termed the spliceosome. The mechanism and regulation of pre-mRNA splicing, and the sub-nuclear organisation of the spliceosomal machinery in higher plants is reviewed here. Heterologous introns are often not processed in higher plants indicating that, although highly conserved, the process of pre-mRNA splicing in plants exhibits significant differences that distinguish it from splicing in yeast and mammals. A fundamental distinguishing feature is the presence of and requirement for AU or U-rich intron sequence in higher-plant pre-mRNA splicing. In this review we document the properties of higher-plant introns and trans-acting spliceosomal components and discuss the means by which these elements combine to determine the accuracy and efficiency of pre-mRNA processing. We also detail examples of how introns can effect regulated gene expression by affecting the nature and abundance of mRNA in plants and list the effects of environmental stresses on splicing. Spliceosomal components exhibit a distinct pattern of organisation in higher-plant nuclei. Effective probes that reveal this pattern have only recently become available, but the domains in which spliceosomal components concentrate were identified in plant nuclei as enigmatic structures some sixty years ago. The organisation of spliceosomal components in plant nuclei is reviewed and these recent observations are unified with previous cytochemical and ultrastructural studies of plant ribonuleoprotein domains.
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Affiliation(s)
- G G Simpson
- Friedrich Miescher-Institut, Basel, Switzerland
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15
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Ulmasov T, Larkin RM, Guilfoyle TJ. Association between 36- and 13.6-kDa alpha-like subunits of Arabidopsis thaliana RNA polymerase II. J Biol Chem 1996; 271:5085-94. [PMID: 8617787 DOI: 10.1074/jbc.271.9.5085] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Two subunits in RNA polymerase II (e.g. RPB3 and RPB11 in yeast) and two subunits common to RNA polymerases I and III (e.g. AC40 and AC19 in yeast) contain one or two motifs related to the alpha subunit in prokaryotic RNA polymerases. We have sequenced two different cDNAs (AtRPB36a and AtRPB36b), the two corresponding genes from Arabidopsis thaliana that are homologs of yeast RPB3, and an Arabidopsis cDNA (AtRPB13.6) that is a homolog of yeast RPB11. The B36a subunit is the predominant B36 subunit associated with RNA polymerase II purified from Arabidopsis suspension culture cells, and this subunit has a stoichiometry of about 1. Results from protein association assays showed that the B36a and B36b subunits did not associate, but each of these subunits did associate with the B13.6 subunit in vivo and in vitro. Two motifs in the B36b subunit related to the prokaryotic alpha subunit were shown to be required for the in vitro interactions with the B13.6 subunit. Our results suggest that the B36 and B13.6 subunits associate to form heterodimers in Arabidopsis RNA polymerase II like the AC40 and AC19 heterodimers reported for yeast RNA polymerases I and III but unlike the B44 homodimers reported for yeast RNA polymerase II.
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Affiliation(s)
- T Ulmasov
- Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA
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Ulmasov T, Larkin RM, Guilfoyle TJ. Arabidopsis expresses two genes that encode polypeptides similar to the yeast RNA polymerase I and III AC40 subunit. Gene X 1995; 167:203-7. [PMID: 8566778 DOI: 10.1016/0378-1119(95)00643-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A 40-kDa subunit in eukaryotic RNA polymerases (Pol) I and III (e.g., yeast yAC40) is related in a part of its aa sequence to the alpha subunit of prokaryotic Pol and to a 35-44-kDa subunit in Pol II (e.g., yeast yB44). We have cloned two cDNAs, AtRPAC42 and AtRPAC43, from an Arabidopsis thaliana (At) (ecotype Columbia) lambda Yes expression library that encode Pol I and III subunits related to yAC40. The aa sequences derived from the cDNA clones were found to be 72% identical to each other and 40% identical to yeast Pol I and III subunits yAC40, but only 30% identical to yeast Pol II subunit yB44. While most other nuclear Pol genes identified to date are single-copy genes, two genes encode 42 and 43-kDa subunits of At Pol I and/or III. A 42-kDa subunit with identical mobility in SDS-PAGE to the aAC42 in vitro translated subunit is found in Pol III purified from At suspension culture cells.
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Affiliation(s)
- T Ulmasov
- Department of Biochemistry, University of Missouri, Columbia 65211, USA
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17
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Klahre U, Hemmings-Mieszczak M, Filipowicz W. Extreme heterogeneity of polyadenylation sites in mRNAs encoding chloroplast RNA-binding proteins in Nicotiana plumbaginifolia. PLANT MOLECULAR BIOLOGY 1995; 28:569-74. [PMID: 7632924 DOI: 10.1007/bf00020402] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We have previously characterized nuclear cDNA clones encoding two RNA binding proteins, CP-RBP30 and CP-RBP-31, which are targeted to chloroplasts in Nicotiana plumbaginifolia. In this report we describe the analysis of the 3'-untranslated regions (3'-UTRs) in 22 CP-RBP30 and 8 CP-RBP31 clones which reveals that mRNAs encoding both proteins have a very complex polyadenylation pattern. Fourteen distinct poly(A) sites were identified among CP-RBP30 clones and four sites among the CP-RBP31 clones. The authenticity of the sites was confirmed by RNase A/T1 mapping of N. plumbaginifolia RNA. CP-RBP30 provides an extreme example of the heterogeneity known to be a feature of mRNA polyadenylation in higher plants. Using PCR we have demonstrated that CP-RBP genes in N. plumbaginifolia and N. sylvestris, in addition to the previously described introns interrupting the coding region, contain an intron located in the 3' non-coding part of the gene. In the case of the CP-RBP31, we have identified one polyadenylation event occurring in this intron.
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Affiliation(s)
- U Klahre
- Friedrich Miescher-Institut, Basel, Switzerland
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18
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Klenk HP, Zilllg W, Lanzendorfer M, Grampp B, Palm P. Location of Protist Lineages in a Phylogenetic Tree Inferred from Sequences of DNA-dependent RNA Polymerases. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0003-9365(11)80317-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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19
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Bakó L, Nuotio S, Dudits D, Schell J, Koncz C. RNAPII: a specific target for the cell cycle kinase complex. Results Probl Cell Differ 1994; 20:25-64. [PMID: 8036318 DOI: 10.1007/978-3-540-48037-2_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- L Bakó
- Institute of Plant Physiology, Hungarian Academy of Sciences, Szeged
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20
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Luehrsen KR, Taha S, Walbot V. Nuclear pre-mRNA processing in higher plants. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1994; 47:149-93. [PMID: 8016320 DOI: 10.1016/s0079-6603(08)60252-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- K R Luehrsen
- Department of Biological Sciences, Stanford University, California 94305
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21
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Ulmasov T, Guilfoyle T. Sequence of the fifth largest subunit of RNA polymerase II from plants. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)50071-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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22
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Barron-Casella E, Corden JL. Conservation of the mammalian RNA polymerase II largest-subunit C-terminal domain. J Mol Evol 1992; 35:405-10. [PMID: 1487824 DOI: 10.1007/bf00171818] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have isolated and sequenced a portion of the gene encoding the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II from three mammals. These mammalian sequences include one rodent and two primate CTDs. Comparisons of the new sequences to mouse and Chinese hamster show a high degree of conservation among the mammalian CTDs. Due to synonymous codon usage, the nucleotide differences between hamster, rat, ape, and human result in no amino acid changes. The amino acid sequence for the mouse CTD appears to have one different amino acid when compared to the other four sequences. Therefore, except for the one variation in mouse, all of the known mammalian CTDs have identical amino acid sequences. This is in marked contrast to the situation among more divergent species. The present study suggests that there is a strong evolutionary pressure to maintain the primary structure of the mammalian CTD.
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Affiliation(s)
- E Barron-Casella
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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