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Xiao J, Turner JJ, Kõivomägi M, Skotheim JM. Whi5 hypo- and hyper-phosphorylation dynamics control cell-cycle entry and progression. Curr Biol 2024; 34:2434-2447.e5. [PMID: 38749424 PMCID: PMC11247822 DOI: 10.1016/j.cub.2024.04.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/18/2024] [Accepted: 04/23/2024] [Indexed: 05/28/2024]
Abstract
Progression through the cell cycle depends on the phosphorylation of key substrates by cyclin-dependent kinases. In budding yeast, these substrates include the transcriptional inhibitor Whi5 that regulates G1/S transition. In early G1 phase, Whi5 is hypo-phosphorylated and inhibits the Swi4/Swi6 (SBF) complex that promotes transcription of the cyclins CLN1 and CLN2. In late G1, Whi5 is rapidly hyper-phosphorylated by Cln1 and Cln2 in complex with the cyclin-dependent kinase Cdk1. This hyper-phosphorylation inactivates Whi5 and excludes it from the nucleus. Here, we set out to determine the molecular mechanisms responsible for Whi5's multi-site phosphorylation and how they regulate the cell cycle. To do this, we first identified the 19 Whi5 sites that are appreciably phosphorylated and then determined which of these sites are responsible for G1 hypo-phosphorylation. Mutation of 7 sites removed G1 hypo-phosphorylation, increased cell size, and delayed the G1/S transition. Moreover, the rapidity of Whi5 hyper-phosphorylation in late G1 depends on "priming" sites that dock the Cks1 subunit of Cln1,2-Cdk1 complexes. Hyper-phosphorylation is crucial for Whi5 nuclear export, normal cell size, full expression of SBF target genes, and timely progression through both the G1/S transition and S/G2/M phases. Thus, our work shows how Whi5 phosphorylation regulates the G1/S transition and how it is required for timely progression through S/G2/M phases and not only G1 as previously thought.
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Affiliation(s)
- Jordan Xiao
- Department of Biology, Stanford University, 327 Campus Dr., Stanford, CA 94305, USA
| | - Jonathan J Turner
- Department of Biology, Stanford University, 327 Campus Dr., Stanford, CA 94305, USA
| | - Mardo Kõivomägi
- Department of Biology, Stanford University, 327 Campus Dr., Stanford, CA 94305, USA; Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, 37 Convent Dr., Bethesda, MD 20892, USA.
| | - Jan M Skotheim
- Department of Biology, Stanford University, 327 Campus Dr., Stanford, CA 94305, USA; Chan Zuckerberg Biohub, 499 Illinois St., San Francisco, CA 94158, USA.
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2
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Sugiyama H, Goto Y, Kondo Y, Coudreuse D, Aoki K. Live-cell imaging defines a threshold in CDK activity at the G2/M transition. Dev Cell 2024; 59:545-557.e4. [PMID: 38228139 DOI: 10.1016/j.devcel.2023.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 10/05/2023] [Accepted: 12/21/2023] [Indexed: 01/18/2024]
Abstract
Cyclin-dependent kinase (CDK) determines the temporal ordering of the cell cycle phases. However, despite significant progress in studying regulators of CDK and phosphorylation patterns of CDK substrates at the population level, it remains elusive how CDK regulators coordinately affect CDK activity at the single-cell level and how CDK controls the temporal order of cell cycle events. Here, we elucidate the dynamics of CDK activity in fission yeast and mammalian cells by developing a CDK activity biosensor, Eevee-spCDK. We find that although CDK activity does not necessarily correlate with cyclin levels, it converges to the same level around mitotic onset in several mutant backgrounds, including pom1Δ cells and wee1 or cdc25 overexpressing cells. These data provide direct evidence that cells enter the M phase when CDK activity reaches a high threshold, consistent with the quantitative model of cell cycle progression in fission yeast.
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Affiliation(s)
- Hironori Sugiyama
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Yuhei Goto
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Basic Biology Program, Graduate Institute for Advanced Studies, SOKENDAI, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Yohei Kondo
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Basic Biology Program, Graduate Institute for Advanced Studies, SOKENDAI, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Damien Coudreuse
- Institute of Biochemistry and Cellular Genetics, UMR 5095, CNRS, Bordeaux University, 33077 Bordeaux, France
| | - Kazuhiro Aoki
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Basic Biology Program, Graduate Institute for Advanced Studies, SOKENDAI, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan.
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3
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Xiao J, Turner JJ, Kõivomägi M, Skotheim JM. Whi5 hypo- and hyper-phosphorylation dynamics control cell cycle entry and progression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.02.565392. [PMID: 37961465 PMCID: PMC10635099 DOI: 10.1101/2023.11.02.565392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Progression through the cell cycle depends on the phosphorylation of key substrates by cyclin-dependent kinases. In budding yeast, these substrates include the transcriptional inhibitor Whi5 that regulates the G1/S transition. In early G1 phase, Whi5 is hypo-phosphorylated and inhibits the SBF complex that promotes transcription of the cyclins CLN1 and CLN2 . In late-G1, Whi5 is rapidly hyper-phosphorylated by Cln1,2 in complex with the cyclin-dependent kinase Cdk1. This hyper-phosphorylation inactivates Whi5 and excludes it from the nucleus. Here, we set out to determine the molecular mechanisms responsible for Whi5's multi-site phosphorylation and how they regulate the cell cycle. To do this, we first identified the 19 Whi5 sites that are appreciably phosphorylated and then determined which of these sites are responsible for G1 hypo-phosphorylation. Mutation of 7 sites removed G1 hypo-phosphorylation, increased cell size, and delayed the G1/S transition. Moreover, the rapidity of Whi5 hyper-phosphorylation in late G1 depends on 'priming' sites that dock the Cks1 subunit of Cln1,2-Cdk1 complexes. Hyper-phosphorylation is crucial for Whi5 nuclear export, normal cell size, full expression of SBF target genes, and timely progression through both the G1/S transition and S/G2/M phases. Thus, our work shows how Whi5 phosphorylation regulates the G1/S transition and how it is required for timely progression through S/G2/M phases and not only G1 as previously thought.
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4
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Arnosti DN. Soft repression and chromatin modification by conserved transcriptional corepressors. Enzymes 2023; 53:69-96. [PMID: 37748837 DOI: 10.1016/bs.enz.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Transcriptional regulation in eukaryotic cells involves the activity of multifarious DNA-binding transcription factors and recruited corepressor complexes. Together, these complexes interact with the core transcriptional machinery, chromatin, and nuclear environment to effect complex patterns of gene regulation. Much focus has been paid to the action of master regulatory switches that are key to developmental and environmental responses, as these genetic elements have important phenotypic effects. The regulation of widely-expressed metabolic control genes has been less well studied, particularly in cases in which physically-interacting repressors and corepressors have subtle influences on steady-state expression. This latter phenomenon, termed "soft repression" is a topic of increasing interest as genomic approaches provide ever more powerful tools to uncover the significance of this level of control. This review provides an oversight of classic and current approaches to the study of transcriptional repression in eukaryotic systems, with a specific focus on opportunities and challenges that lie ahead in the study of soft repression.
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Affiliation(s)
- David N Arnosti
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States.
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5
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Merényi Z, Krizsán K, Sahu N, Liu XB, Bálint B, Stajich JE, Spatafora JW, Nagy LG. Genomes of fungi and relatives reveal delayed loss of ancestral gene families and evolution of key fungal traits. Nat Ecol Evol 2023; 7:1221-1231. [PMID: 37349567 PMCID: PMC10406608 DOI: 10.1038/s41559-023-02095-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 05/11/2023] [Indexed: 06/24/2023]
Abstract
Fungi are ecologically important heterotrophs that have radiated into most niches on Earth and fulfil key ecological services. Despite intense interest in their origins, major genomic trends of their evolutionary route from a unicellular opisthokont ancestor to derived multicellular fungi remain poorly known. Here we provide a highly resolved genome-wide catalogue of gene family changes across fungal evolution inferred from the genomes of 123 fungi and relatives. We show that a dominant trend in early fungal evolution has been the gradual shedding of protist genes and the punctuated emergence of innovation by two main gene duplication events. We find that the gene content of non-Dikarya fungi resembles that of unicellular opisthokonts in many respects, owing to the conservation of protist genes in their genomes. The most rapidly duplicating gene groups included extracellular proteins and transcription factors, as well as ones linked to the coordination of nutrient uptake with growth, highlighting the transition to a sessile osmotrophic feeding strategy and subsequent lifestyle evolution as important elements of early fungal history. These results suggest that the genomes of pre-fungal ancestors evolved into the typical filamentous fungal genome by a combination of gradual gene loss, turnover and several large duplication events rather than by abrupt changes. Consequently, the taxonomically defined Fungi represents a genomically non-uniform assemblage of species.
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Affiliation(s)
- Zsolt Merényi
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Krisztina Krizsán
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
- Institute of Forensic Genetics, Hungarian Institute for Forensic Sciences, Budapest, Hungary
| | - Neha Sahu
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Xiao-Bin Liu
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Balázs Bálint
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Jason E Stajich
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA, USA
| | - Joseph W Spatafora
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - László G Nagy
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary.
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6
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Carreras-Villaseñor N, Martínez-Rodríguez LA, Ibarra-Laclette E, Monribot-Villanueva JL, Rodríguez-Haas B, Guerrero-Analco JA, Sánchez-Rangel D. The biological relevance of the FspTF transcription factor, homologous of Bqt4, in Fusarium sp. associated with the ambrosia beetle Xylosandrus morigerus. Front Microbiol 2023; 14:1224096. [PMID: 37520351 PMCID: PMC10375492 DOI: 10.3389/fmicb.2023.1224096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 06/22/2023] [Indexed: 08/01/2023] Open
Abstract
Transcription factors in phytopathogenic fungi are key players due to their gene expression regulation leading to fungal growth and pathogenicity. The KilA-N family encompasses transcription factors unique to fungi, and the Bqt4 subfamily is included in it and is poorly understood in filamentous fungi. In this study, we evaluated the role in growth and pathogenesis of the homologous of Bqt4, FspTF, in Fusarium sp. isolated from the ambrosia beetle Xylosandrus morigerus through the characterization of a CRISPR/Cas9 edited strain in Fsptf. The phenotypic analysis revealed that TF65-6, the edited strain, modified its mycelia growth and conidia production, exhibited affectation in mycelia and culture pigmentation, and in the response to certain stress conditions. In addition, the plant infection process was compromised. Untargeted metabolomic and transcriptomic analysis, clearly showed that FspTF may regulate secondary metabolism, transmembrane transport, virulence, and diverse metabolic pathways such as lipid metabolism, and signal transduction. These data highlight for the first time the biological relevance of an orthologue of Bqt4 in Fusarium sp. associated with an ambrosia beetle.
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Affiliation(s)
- Nohemí Carreras-Villaseñor
- Laboratorios de Biología Molecular y Fitopatología, Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
| | - Luis A. Martínez-Rodríguez
- Laboratorios de Biología Molecular y Fitopatología, Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
| | - Enrique Ibarra-Laclette
- Laboratorio de Genómica y Transcriptómica, Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
| | - Juan L. Monribot-Villanueva
- Laboratorio de Química de Productos Naturales, Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
| | - Benjamín Rodríguez-Haas
- Laboratorios de Biología Molecular y Fitopatología, Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
| | - José A. Guerrero-Analco
- Laboratorio de Química de Productos Naturales, Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
| | - Diana Sánchez-Rangel
- Laboratorios de Biología Molecular y Fitopatología, Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
- Investigadora Por Mexico-CONAHCyT, Xalapa, Mexico
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7
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Abstract
Most cells live in environments that are permissive for proliferation only a small fraction of the time. Entering quiescence enables cells to survive long periods of nondivision and reenter the cell cycle when signaled to do so. Here, we describe what is known about the molecular basis for quiescence in Saccharomyces cerevisiae, with emphasis on the progress made in the last decade. Quiescence is triggered by depletion of an essential nutrient. It begins well before nutrient exhaustion, and there is extensive crosstalk between signaling pathways to ensure that all proliferation-specific activities are stopped when any one essential nutrient is limiting. Every aspect of gene expression is modified to redirect and conserve resources. Chromatin structure and composition change on a global scale, from histone modifications to three-dimensional chromatin structure. Thousands of proteins and RNAs aggregate, forming unique structures with unique fates, and the cytoplasm transitions to a glass-like state.
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Affiliation(s)
- Linda L Breeden
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA; ,
| | - Toshio Tsukiyama
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA; ,
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8
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Abstract
The most fundamental feature of cellular form is size, which sets the scale of all cell biological processes. Growth, form, and function are all necessarily linked in cell biology, but we often do not understand the underlying molecular mechanisms nor their specific functions. Here, we review progress toward determining the molecular mechanisms that regulate cell size in yeast, animals, and plants, as well as progress toward understanding the function of cell size regulation. It has become increasingly clear that the mechanism of cell size regulation is deeply intertwined with basic mechanisms of biosynthesis, and how biosynthesis can be scaled (or not) in proportion to cell size. Finally, we highlight recent findings causally linking aberrant cell size regulation to cellular senescence and their implications for cancer therapies.
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Affiliation(s)
- Shicong Xie
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Matthew Swaffer
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, California, USA;
- Chan Zuckerberg Biohub, San Francisco, California, USA
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9
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Abstract
It has been assumed that fungi are characterized by a haploid-dominant life cycle with a general absence of mitosis in the diploid stage (haplontic life cycles). However, this characterization is based largely on information for Dikarya, a group of fungi that contains mushrooms, lichens, molds, yeasts, and most described fungi. We now appreciate that most early-diverging lineages of fungi are not Dikarya and share traits with protists, such as flagellated life stages. Here, we generated an improved phylogeny of the fungi by generating genome sequences of 69 zoosporic fungi. We show, using the estimated heterozygosity of these genomes, that many fungal lineages have diploid-dominant life cycles (diplontic). This finding forces us to rethink the early evolution of the fungal cell. Most of the described species in kingdom Fungi are contained in two phyla, the Ascomycota and the Basidiomycota (subkingdom Dikarya). As a result, our understanding of the biology of the kingdom is heavily influenced by traits observed in Dikarya, such as aerial spore dispersal and life cycles dominated by mitosis of haploid nuclei. We now appreciate that Fungi comprises numerous phylum-level lineages in addition to those of Dikarya, but the phylogeny and genetic characteristics of most of these lineages are poorly understood due to limited genome sampling. Here, we addressed major evolutionary trends in the non-Dikarya fungi by phylogenomic analysis of 69 newly generated draft genome sequences of the zoosporic (flagellated) lineages of true fungi. Our phylogeny indicated five lineages of zoosporic fungi and placed Blastocladiomycota, which has an alternation of haploid and diploid generations, as branching closer to the Dikarya than to the Chytridiomyceta. Our estimates of heterozygosity based on genome sequence data indicate that the zoosporic lineages plus the Zoopagomycota are frequently characterized by diploid-dominant life cycles. We mapped additional traits, such as ancestral cell-cycle regulators, cell-membrane– and cell-wall–associated genes, and the use of the amino acid selenocysteine on the phylogeny and found that these ancestral traits that are shared with Metazoa have been subject to extensive parallel loss across zoosporic lineages. Together, our results indicate a gradual transition in the genetics and cell biology of fungi from their ancestor and caution against assuming that traits measured in Dikarya are typical of other fungal lineages.
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10
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Schmoller KM, Lanz MC, Kim J, Koivomagi M, Qu Y, Tang C, Kukhtevich IV, Schneider R, Rudolf F, Moreno DF, Aldea M, Lucena R, Skotheim JM. Whi5 is diluted and protein synthesis does not dramatically increase in pre- Start G1. Mol Biol Cell 2022; 33:lt1. [PMID: 35482510 PMCID: PMC9282012 DOI: 10.1091/mbc.e21-01-0029] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Kurt M Schmoller
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Germany
| | - Michael C Lanz
- Department of Biology, Stanford University, Stanford CA 94305
| | - Jacob Kim
- Department of Biology, Stanford University, Stanford CA 94305
| | - Mardo Koivomagi
- Department of Biology, Stanford University, Stanford CA 94305
| | - Yimiao Qu
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Chao Tang
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Igor V Kukhtevich
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Germany
| | - Robert Schneider
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Germany
| | - Fabian Rudolf
- D-BSSE, ETH Zurich and Swiss Institute of Bioinformatics, Zurich, Switzerland
| | - David F Moreno
- Molecular Biology Institute of Barcelona, CSIC, Catalonia, Spain
| | - Martí Aldea
- Molecular Biology Institute of Barcelona, CSIC, Catalonia, Spain
| | - Rafael Lucena
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford CA 94305
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11
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Laundon D, Chrismas N, Bird K, Thomas S, Mock T, Cunliffe M. A cellular and molecular atlas reveals the basis of chytrid development. eLife 2022; 11:73933. [PMID: 35227375 PMCID: PMC8887899 DOI: 10.7554/elife.73933] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 02/01/2022] [Indexed: 12/26/2022] Open
Abstract
The chytrids (phylum Chytridiomycota) are a major fungal lineage of ecological and evolutionary importance. Despite their importance, many fundamental aspects of chytrid developmental and cell biology remain poorly understood. To address these knowledge gaps, we combined quantitative volume electron microscopy and comparative transcriptome profiling to create an 'atlas' of the cellular and molecular basis of the chytrid life cycle, using the model chytrid Rhizoclosmatium globosum. From our developmental atlas, we describe the transition from the transcriptionally inactive free-swimming zoospore to the more biologically complex germling, and show that lipid processing is multifaceted and dynamic throughout the life cycle. We demonstrate that the chytrid apophysis is a compartmentalised site of high intracellular trafficking, linking the feeding/attaching rhizoids to the reproductive zoosporangium, and constituting division of labour in the chytrid cell plan. We provide evidence that during zoosporogenesis, zoospores display amoeboid morphologies and exhibit endocytotic cargo transport from the interstitial maternal cytoplasm. Taken together, our results reveal insights into chytrid developmental biology and provide a basis for future investigations into non-dikaryan fungal cell biology.
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Affiliation(s)
- Davis Laundon
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, United Kingdom.,School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
| | - Nathan Chrismas
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, United Kingdom
| | - Kimberley Bird
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, United Kingdom
| | - Seth Thomas
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, United Kingdom
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
| | - Michael Cunliffe
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, United Kingdom.,School of Biological and Marine Sciences, University of Plymouth, Plymouth, United Kingdom
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12
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Irwin NAT, Pittis AA, Richards TA, Keeling PJ. Systematic evaluation of horizontal gene transfer between eukaryotes and viruses. Nat Microbiol 2021; 7:327-336. [PMID: 34972821 DOI: 10.1038/s41564-021-01026-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 11/12/2021] [Indexed: 01/19/2023]
Abstract
Gene exchange between viruses and their hosts acts as a key facilitator of horizontal gene transfer and is hypothesized to be a major driver of evolutionary change. Our understanding of this process comes primarily from bacteria and phage co-evolution, but the mode and functional importance of gene transfers between eukaryotes and their viruses remain anecdotal. Here we systematically characterized viral-eukaryotic gene exchange across eukaryotic and viral diversity, identifying thousands of transfers and revealing their frequency, taxonomic distribution and projected functions. Eukaryote-derived viral genes, abundant in the Nucleocytoviricota, highlighted common strategies for viral host-manipulation, including metabolic reprogramming, proteolytic degradation and extracellular modification. Furthermore, viral-derived eukaryotic genes implicate genetic exchange in the early evolution and diversification of eukaryotes, particularly through viral-derived glycosyltransferases, which have impacted structures as diverse as algal cell walls, trypanosome mitochondria and animal tissues. These findings illuminate the nature of viral-eukaryotic gene exchange and its impact on the evolution of viruses and their eukaryotic hosts.
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Affiliation(s)
- Nicholas A T Irwin
- Merton College, University of Oxford, Oxford, UK. .,Department of Zoology, University of Oxford, Oxford, UK. .,Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Alexandros A Pittis
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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13
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Stephan OOH. Interactions, structural aspects, and evolutionary perspectives of the yeast 'START'-regulatory network. FEMS Yeast Res 2021; 22:6461095. [PMID: 34905017 DOI: 10.1093/femsyr/foab064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 12/11/2021] [Indexed: 11/12/2022] Open
Abstract
Molecular signal transduction networks which conduct transcription at the G1 to S phase transition of the eukaryotic cell division cycle have been identified in diverse taxa from mammals to baker´s yeast with analogous functional organization. However, regarding some network components, such as the transcriptional regulators STB1 and WHI5, only few orthologs exist which are confined to individual Saccharomycotina species. While Whi5 has been characterized as yeast analog of human Rb protein, in the particular case of Stb1 (Sin three binding protein 1) identification of functional analogs emerges as difficult because to date its exact functionality still remains obscured. By aiming to resolve Stb1´s enigmatic role this Perspectives article especially surveys works covering relations between Cyclin/CDKs, the heteromeric transcription factor complexes SBF (Swi4/Swi6) and MBF (Mbp1/Swi6), as well as additional coregulators (Whi5, Sin3, Rpd3, Nrm1) which are collectively associated with the orderly transcription at 'Start' of the Saccharomyces cerevisiae cell cycle. In this context, interaction capacities of the Sin3-scaffold protein are widely surveyed because its four PAH domains (Paired Amphiphatic Helix) represent a 'recruitment-code' for gene-specific targeting of repressive histone deacetylase activity (Rpd3) via different transcription factors. Here Stb1 plays a role in Sin3´s action on transcription at the G1/S-boundary. Through bioinformatic analyses a potential Sin3-interaction domain (SID) was detected in Stb1, and beyond that, connections within the G1/S-regulatory network are discussed in structural and evolutionary context thereby providing conceptual perspectives.
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Affiliation(s)
- Octavian O H Stephan
- Department of Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Bavaria, Germany
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14
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Prostak SM, Fritz-Laylin LK. Laboratory Maintenance of the Chytrid Fungus Batrachochytrium dendrobatidis. Curr Protoc 2021; 1:e309. [PMID: 34870903 DOI: 10.1002/cpz1.309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The chytrid fungus Batrachochytrium dendrobatidis (Bd) is a causative agent of chytridiomycosis, a skin disease associated with amphibian population declines around the world. Despite the major impact Bd is having on global ecosystems, much of Bd's basic biology remains unstudied. In addition to revealing mechanisms driving the spread of chytridiomycosis, studying Bd can shed light on the evolution of key fungal traits because chytrid fungi, including Bd, diverged before the radiation of the Dikaryotic fungi (multicellular fungi and yeast). Studying Bd in the laboratory is, therefore, of growing interest to a wide range of scientists, ranging from herpetologists and disease ecologists to molecular, cell, and evolutionary biologists. This protocol describes how to maintain developmentally synchronized liquid cultures of Bd for use in the laboratory, how to grow Bd on solid media, as well as cryopreservation and revival of frozen stocks. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Reviving cryopreserved Bd cultures Basic Protocol 2: Establishing synchronized liquid cultures of Bd Basic Protocol 3: Regular maintenance of synchronous Bd in liquid culture Alternate Protocol 1: Regular maintenance of asynchronous Bd in liquid culture Basic Protocol 4: Regular maintenance of synchronous Bd on solid medium Alternate Protocol 2: Starting a culture on solid medium from a liquid culture Basic Protocol 5: Cryopreservation of Bd.
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Affiliation(s)
- Sarah M Prostak
- Department of Biology, University of Massachusetts, Amherst, Massachusetts
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15
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Abstract
Cell growth can drive progression into the cell cycle by diluting a diverse set of cell-cycle inhibitors in yeast, animal, and plant cells. Inhibitor dilution mechanisms implement cell-size control when large and small cells inherit a similar number of inhibitor molecules, and new work shows that these mechanisms in plant cells include specific degradation and chromatin-partitioning components.
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Affiliation(s)
- Shicong Xie
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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16
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Pirincci Ercan D, Chrétien F, Chakravarty P, Flynn HR, Snijders AP, Uhlmann F. Budding yeast relies on G 1 cyclin specificity to couple cell cycle progression with morphogenetic development. SCIENCE ADVANCES 2021; 7:eabg0007. [PMID: 34088668 PMCID: PMC8177710 DOI: 10.1126/sciadv.abg0007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/19/2021] [Indexed: 05/04/2023]
Abstract
Two models have been put forward for cyclin-dependent kinase (Cdk) control of the cell cycle. In the qualitative model, cell cycle events are ordered by distinct substrate specificities of successive cyclin waves. Alternatively, in the quantitative model, the gradual rise of Cdk activity from G1 phase to mitosis leads to ordered substrate phosphorylation at sequential thresholds. Here, we study the relative contributions of qualitative and quantitative Cdk control in Saccharomyces cerevisiae All S phase and mitotic cyclins can be replaced by a single mitotic cyclin, albeit at the cost of reduced fitness. A single cyclin can also replace all G1 cyclins to support ordered cell cycle progression, fulfilling key predictions of the quantitative model. However, single-cyclin cells fail to polarize or grow buds and thus cannot survive. Our results suggest that budding yeast has become dependent on G1 cyclin specificity to couple cell cycle progression to essential morphogenetic events.
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Affiliation(s)
| | - Florine Chrétien
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
| | - Probir Chakravarty
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, London, UK
| | - Helen R Flynn
- Proteomics Science Technology Platform, The Francis Crick Institute, London, UK
| | | | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK.
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17
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Prostak SM, Robinson KA, Titus MA, Fritz-Laylin LK. The actin networks of chytrid fungi reveal evolutionary loss of cytoskeletal complexity in the fungal kingdom. Curr Biol 2021; 31:1192-1205.e6. [DOI: 10.1016/j.cub.2021.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 11/05/2020] [Accepted: 01/04/2021] [Indexed: 12/16/2022]
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18
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Ros-Rocher N, Pérez-Posada A, Leger MM, Ruiz-Trillo I. The origin of animals: an ancestral reconstruction of the unicellular-to-multicellular transition. Open Biol 2021; 11:200359. [PMID: 33622103 PMCID: PMC8061703 DOI: 10.1098/rsob.200359] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
How animals evolved from a single-celled ancestor, transitioning from a unicellular lifestyle to a coordinated multicellular entity, remains a fascinating question. Key events in this transition involved the emergence of processes related to cell adhesion, cell–cell communication and gene regulation. To understand how these capacities evolved, we need to reconstruct the features of both the last common multicellular ancestor of animals and the last unicellular ancestor of animals. In this review, we summarize recent advances in the characterization of these ancestors, inferred by comparative genomic analyses between the earliest branching animals and those radiating later, and between animals and their closest unicellular relatives. We also provide an updated hypothesis regarding the transition to animal multicellularity, which was likely gradual and involved the use of gene regulatory mechanisms in the emergence of early developmental and morphogenetic plans. Finally, we discuss some new avenues of research that will complement these studies in the coming years.
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Affiliation(s)
- Núria Ros-Rocher
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Catalonia, Spain
| | - Alberto Pérez-Posada
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Catalonia, Spain.,Centro Andaluz de Biología del Desarrollo (CSIC-Universidad Pablo de Olavide), Carretera de Utrera Km 1, 41013 Sevilla, Andalusia, Spain
| | - Michelle M Leger
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Catalonia, Spain
| | - Iñaki Ruiz-Trillo
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Catalonia, Spain.,Departament de Genètica, Microbiologia i Estadística, Institut de Recerca de la Biodiversitat, Universitat de Barcelona, Avinguda Diagonal 643, 08028 Barcelona, Catalonia, Spain.,ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
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19
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Direct Regulation of DNA Repair by E2F and RB in Mammals and Plants: Core Function or Convergent Evolution? Cancers (Basel) 2021; 13:cancers13050934. [PMID: 33668093 PMCID: PMC7956360 DOI: 10.3390/cancers13050934] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/10/2021] [Accepted: 02/19/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Retinoblastoma (RB) proteins and E2F transcription factors partner together to regulate the cell cycle in many eukaryotic organisms. In organisms that lack one or both of these proteins, other proteins have taken on the essential function of cell cycle regulation. RB and E2F also have important functions outside of the cell cycle, including DNA repair. This review summarizes the non-canonical functions of RB and E2F in maintaining genome integrity and raises the question of whether such functions have always been present or have evolved more recently. Abstract Members of the E2F transcription factor family regulate the expression of genes important for DNA replication and mitotic cell division in most eukaryotes. Homologs of the retinoblastoma (RB) tumor suppressor inhibit the activity of E2F factors, thus controlling cell cycle progression. Organisms such as budding and fission yeast have lost genes encoding E2F and RB, but have gained genes encoding other proteins that take on E2F and RB cell cycle-related functions. In addition to regulating cell proliferation, E2F and RB homologs have non-canonical functions outside the mitotic cell cycle in a variety of eukaryotes. For example, in both mammals and plants, E2F and RB homologs localize to DNA double-strand breaks (DSBs) and directly promote repair by homologous recombination (HR). Here, we discuss the parallels between mammalian E2F1 and RB and their Arabidopsis homologs, E2FA and RB-related (RBR), with respect to their recruitment to sites of DNA damage and how they help recruit repair factors important for DNA end resection. We also explore the question of whether this role in DNA repair is a conserved ancient function of the E2F and RB homologs in the last eukaryotic common ancestor or whether this function evolved independently in mammals and plants.
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20
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Bandyopadhyay S, Bhaduri S, Örd M, Davey NE, Loog M, Pryciak PM. Comprehensive Analysis of G1 Cyclin Docking Motif Sequences that Control CDK Regulatory Potency In Vivo. Curr Biol 2020; 30:4454-4466.e5. [PMID: 32976810 PMCID: PMC8009629 DOI: 10.1016/j.cub.2020.08.099] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 11/17/2022]
Abstract
Many protein-modifying enzymes recognize their substrates via docking motifs, but the range of functionally permissible motif sequences is often poorly defined. During eukaryotic cell division, cyclin-specific docking motifs help cyclin-dependent kinases (CDKs) phosphorylate different substrates at different stages, thus enforcing a temporally ordered series of events. In budding yeast, CDK substrates with Leu/Pro-rich (LP) docking motifs are recognized by Cln1/2 cyclins in late G1 phase, yet the key sequence features of these motifs were unknown. Here, we comprehensively analyze LP motif requirements in vivo by combining a competitive growth assay with deep mutational scanning. We quantified the effect of all single-residue replacements in five different LP motifs by using six distinct G1 cyclins from diverse fungi including medical and agricultural pathogens. The results uncover substantial tolerance for deviations from the consensus sequence, plus requirements at some positions that are contingent on the favorability of other motif residues. They also reveal the basis for variations in functional potency among wild-type motifs, and allow derivation of a quantitative matrix that predicts the strength of other candidate motif sequences. Finally, we find that variation in docking motif potency can advance or delay the time at which CDK substrate phosphorylation occurs, and thereby control the temporal ordering of cell cycle regulation. The overall results provide a general method for surveying viable docking motif sequences and quantifying their potency in vivo, and they reveal how variations in docking strength can tune the degree and timing of regulatory modifications.
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Affiliation(s)
- Sushobhana Bandyopadhyay
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Samyabrata Bhaduri
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Mihkel Örd
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Norman E Davey
- Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Mart Loog
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Peter M Pryciak
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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21
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Espinal-Centeno A, Dipp-Álvarez M, Saldaña C, Bako L, Cruz-Ramírez A. Conservation analysis of core cell cycle regulators and their transcriptional behavior during limb regeneration in Ambystoma mexicanum. Mech Dev 2020; 164:103651. [PMID: 33127453 DOI: 10.1016/j.mod.2020.103651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 10/01/2020] [Accepted: 10/19/2020] [Indexed: 11/18/2022]
Abstract
Ambystoma mexicanum (axolotl) has been one of the major experimental models for the study of regeneration during the past 100 years. Axolotl limb regeneration takes place through a multi-stage and complex developmental process called epimorphosis that involves diverse events of cell reprogramming. Such events start with dedifferentiation of somatic cells and the proliferation of quiescent stem cells to generate a population of proliferative cells called blastema. Once the blastema reaches a mature stage, cells undergo progressive differentiation into the diverse cell lineages that will form the new limb. Such pivotal cell reprogramming phenomena depend on the fine-tuned regulation of the cell cycle in each regeneration stage, where cell populations display specific proliferative capacities and differentiation status. The axolotl genome has been fully sequenced and released recently, and diverse RNA-seq approaches have also been generated, enabling the identification and conservatory analysis of core cell cycle regulators in this species. We report here our results from such analyses and present the transcriptional behavior of key regulatory factors during axolotl limb regeneration. We also found conserved protein interactions between axolotl Cyclin Dependent Kinases 2, 4 and 6 and Cyclins type D and E. Canonical CYC-CDK interactions that play major roles in modulating cell cycle progression in eukaryotes.
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Affiliation(s)
- Annie Espinal-Centeno
- Molecular and Developmental Complexity Group, Unidad de Genómica Avanzada (U.G.A.-LANGEBIO) CINVESTAV, Irapuato, Mexico; Facultad de Ciencias Naturales, Campus Juriquilla, Universidad Autónoma de Querétaro, Av. de las Ciencias S/N, Juriquilla, Querétaro, Qro. CP 76230, Mexico
| | - Melissa Dipp-Álvarez
- Molecular and Developmental Complexity Group, Unidad de Genómica Avanzada (U.G.A.-LANGEBIO) CINVESTAV, Irapuato, Mexico
| | - Carlos Saldaña
- Facultad de Ciencias Naturales, Campus Juriquilla, Universidad Autónoma de Querétaro, Av. de las Ciencias S/N, Juriquilla, Querétaro, Qro. CP 76230, Mexico
| | - Laszlo Bako
- Department of Plant Physiology, Umeå University, Umeå, Sweden.
| | - Alfredo Cruz-Ramírez
- Molecular and Developmental Complexity Group, Unidad de Genómica Avanzada (U.G.A.-LANGEBIO) CINVESTAV, Irapuato, Mexico.
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22
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Abstract
Diversity within the fungal kingdom is evident from the wide range of morphologies fungi display as well as the various ecological roles and industrial purposes they serve. Technological advances, particularly in long-read sequencing, coupled with the increasing efficiency and decreasing costs across sequencing platforms have enabled robust characterization of fungal genomes. These sequencing efforts continue to reveal the rampant diversity in fungi at the genome level. Here, we discuss studies that have furthered our understanding of fungal genetic diversity and genomic evolution. These studies revealed the presence of both small-scale and large-scale genomic changes. In fungi, research has recently focused on many small-scale changes, such as how hypermutation and allelic transmission impact genome evolution as well as how and why a few specific genomic regions are more susceptible to rapid evolution than others. High-throughput sequencing of a diverse set of fungal genomes has also illuminated the frequency, mechanisms, and impacts of large-scale changes, which include chromosome structural variation and changes in chromosome number, such as aneuploidy, polyploidy, and the presence of supernumerary chromosomes. The studies discussed herein have provided great insight into how the architecture of the fungal genome varies within species and across the kingdom and how modern fungi may have evolved from the last common fungal ancestor and might also pave the way for understanding how genomic diversity has evolved in all domains of life.
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Affiliation(s)
- Shelby J. Priest
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
| | - Vikas Yadav
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
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23
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Zatulovskiy E, Zhang S, Berenson DF, Topacio BR, Skotheim JM. Cell growth dilutes the cell cycle inhibitor Rb to trigger cell division. Science 2020; 369:466-471. [PMID: 32703881 PMCID: PMC7489475 DOI: 10.1126/science.aaz6213] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 05/19/2020] [Indexed: 12/21/2022]
Abstract
Cell size is fundamental to cell physiology. For example, cell size determines the spatial scale of organelles and intracellular transport and thereby affects biosynthesis. Although some genes that affect mammalian cell size have been identified, the molecular mechanisms through which cell growth drives cell division have remained elusive. We show that cell growth during the G1 phase of the cell division cycle dilutes the cell cycle inhibitor Retinoblastoma protein (Rb) to trigger division in human cells. RB overexpression increased cell size and G1 duration, whereas RB deletion decreased cell size and removed the inverse correlation between cell size at birth and the duration of the G1 phase. Thus, Rb dilution through cell growth in G1 provides one of the long-sought molecular mechanisms that promotes cell size homeostasis.
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Affiliation(s)
| | - Shuyuan Zhang
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | | | | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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24
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Regulation of Multiple Fission and Cell-Cycle-Dependent Gene Expression by CDKA1 and the Rb-E2F Pathway in Chlamydomonas. Curr Biol 2020; 30:1855-1865.e4. [PMID: 32243861 DOI: 10.1016/j.cub.2020.03.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/06/2020] [Accepted: 03/09/2020] [Indexed: 01/07/2023]
Abstract
The green alga Chlamydomonas proliferates by "multiple fission": a long G1 with >10-fold cell growth followed by multiple rapid divisions. Cells above a critical size threshold are "committed" and will divide independent of light and further cell growth. The number of divisions carried out depends on the initial size of the committed mother cell. Here, I show that CDKA1, the ortholog of the yeast and animal mitotic inducer CDK1, regulates the critical size for commitment. The Rb/E2F/Dp1 pathway regulates division number as well as commitment size. Epistasis analysis indicated that CDKA1 and Rb/E2F/Dp1 regulate multiple fission by distinct mechanisms. Rb-E2F/Dp1 regulates G1/S gene expression in animals and land plants. Transcriptome analysis showed that mat3 or dp1 disruption altered regulation of a large group of cell-division-associated genes with respect to cell size, but not with respect to synchronization timing. In contrast, cdka1 inactivation disturbed both temporal and cell-size regulation of expression. These defects were enhanced by double inactivation of cdka1 and dp1, suggesting interaction between CDKA1 and the Rb-E2F/Dp1 pathways in regulating cell-cycle-specific gene expression and cell-cycle initiation. In the context of a theoretical model for regulation of Chlamydomonas multiple fission, these results suggest that CDKA1 may promote a switch into a division-competent state, and E2F/Dp1 may promote maintenance of this state.
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25
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Medina EM, Robinson KA, Bellingham-Johnstun K, Ianiri G, Laplante C, Fritz-Laylin LK, Buchler NE. Genetic transformation of Spizellomyces punctatus, a resource for studying chytrid biology and evolutionary cell biology. eLife 2020; 9:52741. [PMID: 32392127 PMCID: PMC7213984 DOI: 10.7554/elife.52741] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 04/23/2020] [Indexed: 02/07/2023] Open
Abstract
Chytrids are early-diverging fungi that share features with animals that have been lost in most other fungi. They hold promise as a system to study fungal and animal evolution, but we lack genetic tools for hypothesis testing. Here, we generated transgenic lines of the chytrid Spizellomyces punctatus, and used fluorescence microscopy to explore chytrid cell biology and development during its life cycle. We show that the chytrid undergoes multiple rounds of synchronous nuclear division, followed by cellularization, to create and release many daughter ‘zoospores’. The zoospores, akin to animal cells, crawl using actin-mediated cell migration. After forming a cell wall, polymerized actin reorganizes into fungal-like cortical patches and cables that extend into hyphal-like structures. Actin perinuclear shells form each cell cycle and polygonal territories emerge during cellularization. This work makes Spizellomyces a genetically tractable model for comparative cell biology and understanding the evolution of fungi and early eukaryotes.
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Affiliation(s)
- Edgar M Medina
- University of Program in Genetics and Genomics, Duke University, Durham, United States.,Department of Molecular Genetics and Microbiology, Duke University, Durham, United States
| | - Kristyn A Robinson
- Department of Biology, University of Massachusetts, Amherst, United States
| | | | - Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University, Durham, United States
| | - Caroline Laplante
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, United States
| | | | - Nicolas E Buchler
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, United States
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26
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Zatulovskiy E, Skotheim JM. On the Molecular Mechanisms Regulating Animal Cell Size Homeostasis. Trends Genet 2020; 36:360-372. [PMID: 32294416 PMCID: PMC7162994 DOI: 10.1016/j.tig.2020.01.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/28/2020] [Accepted: 01/28/2020] [Indexed: 12/19/2022]
Abstract
Cell size is fundamental to cell physiology because it sets the scale of intracellular geometry, organelles, and biosynthetic processes. In animal cells, size homeostasis is controlled through two phenomenologically distinct mechanisms. First, size-dependent cell cycle progression ensures that smaller cells delay cell cycle progression to accumulate more biomass than larger cells prior to cell division. Second, size-dependent cell growth ensures that larger and smaller cells grow slower per unit mass than more optimally sized cells. This decade has seen dramatic progress in single-cell technologies establishing the diverse phenomena of cell size control in animal cells. Here, we review this recent progress and suggest pathways forward to determine the underlying molecular mechanisms.
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Affiliation(s)
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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27
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Pérez-Posada A, Dudin O, Ocaña-Pallarès E, Ruiz-Trillo I, Ondracka A. Cell cycle transcriptomics of Capsaspora provides insights into the evolution of cyclin-CDK machinery. PLoS Genet 2020; 16:e1008584. [PMID: 32176685 PMCID: PMC7098662 DOI: 10.1371/journal.pgen.1008584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 03/26/2020] [Accepted: 12/23/2019] [Indexed: 12/19/2022] Open
Abstract
Progression through the cell cycle in eukaryotes is regulated on multiple levels. The main driver of the cell cycle progression is the periodic activity of cyclin-dependent kinase (CDK) complexes. In parallel, transcription during the cell cycle is regulated by a transcriptional program that ensures the just-in-time gene expression. Many core cell cycle regulators are widely conserved in eukaryotes, among them cyclins and CDKs; however, periodic transcriptional programs are divergent between distantly related species. In addition, many otherwise conserved cell cycle regulators have been lost and independently evolved in yeast, a widely used model organism for cell cycle research. For a better understanding of the evolution of the cell cycle regulation in opisthokonts, we investigated the transcriptional program during the cell cycle of the filasterean Capsaspora owczarzaki, a unicellular species closely related to animals. We developed a protocol for cell cycle synchronization in Capsaspora cultures and assessed gene expression over time across the entire cell cycle. We identified a set of 801 periodic genes that grouped into five clusters of expression over time. Comparison with datasets from other eukaryotes revealed that the periodic transcriptional program of Capsaspora is most similar to that of animal cells. We found that orthologues of cyclin A, B and E are expressed at the same cell cycle stages as in human cells and in the same temporal order. However, in contrast to human cells where these cyclins interact with multiple CDKs, Capsaspora cyclins likely interact with a single ancestral CDK1-3. Thus, the Capsaspora cyclin-CDK system could represent an intermediate state in the evolution of animal-like cyclin-CDK regulation. Overall, our results demonstrate that Capsaspora could be a useful unicellular model system for animal cell cycle regulation.
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Affiliation(s)
- Alberto Pérez-Posada
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - Omaya Dudin
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - Eduard Ocaña-Pallarès
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
| | - Iñaki Ruiz-Trillo
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Catalonia, Spain
- ICREA, Barcelona, Catalonia, Spain
| | - Andrej Ondracka
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Catalonia, Spain
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28
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Bloomfield G. The molecular foundations of zygosis. Cell Mol Life Sci 2020; 77:323-330. [PMID: 31203379 PMCID: PMC11105095 DOI: 10.1007/s00018-019-03187-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/27/2019] [Accepted: 06/06/2019] [Indexed: 10/26/2022]
Abstract
Zygosis is the generation of new biological individuals by the sexual fusion of gamete cells. Our current understanding of eukaryotic phylogeny indicates that sex is ancestral to all extant eukaryotes. Although sexual development is extremely diverse, common molecular elements have been retained. HAP2-GCS1, a protein that promotes the fusion of gamete cell membranes that is related in structure to certain viral fusogens, is conserved in many eukaryotic lineages, even though gametes vary considerably in form and behaviour between species. Similarly, although zygotes have dramatically different forms and fates in different organisms, diverse eukaryotes share a common developmental programme in which homeodomain-containing transcription factors play a central role. These common mechanistic elements suggest possible common evolutionary histories that, if correct, would have profound implications for our understanding of eukaryogenesis.
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29
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Medina EM, Walsh E, Buchler NE. Evolutionary innovation, fungal cell biology, and the lateral gene transfer of a viral KilA-N domain. Curr Opin Genet Dev 2019; 58-59:103-110. [PMID: 31600629 DOI: 10.1016/j.gde.2019.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/27/2019] [Accepted: 08/31/2019] [Indexed: 10/25/2022]
Abstract
Fungi are found in diverse ecological niches as primary decomposers, mutualists, or parasites of plants and animals. Although animals and fungi share a common ancestor, fungi dramatically diversified their life cycle, cell biology, and metabolism as they evolved and colonized new niches. This review focuses on a family of fungal transcription factors (Swi4/Mbp1, APSES, Xbp1, Bqt4) derived from the lateral gene transfer of a KilA-N domain commonly found in prokaryotic and eukaryotic DNA viruses. These virus-derived fungal regulators play central roles in cell cycle, morphogenesis, sexual differentiation, and quiescence. We consider the possible origins of KilA-N and how this viral DNA binding domain came to be intimately associated with fungal processes.
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Affiliation(s)
- Edgar M Medina
- University Program in Genetics and Genomics, Duke University, Durham, NC 27710, USA
| | - Evan Walsh
- Bioinformatics Program, North Carolina State University, Raleigh, NC 27607, USA
| | - Nicolas E Buchler
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27606, USA.
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Roque Marques KM, do Desterro MR, de Arruda SM, de Araújo Neto LN, do Carmo Alves de Lima M, de Almeida SMV, da Silva ECD, de Aquino TM, da Silva-Júnior EF, de Araújo-Júnior JX, de M Silva M, de A Dantas MD, Santos JCC, Figueiredo IM, Bazin MA, Marchand P, da Silva TG, Mendonça Junior FJB. 5-Nitro-Thiophene-Thiosemicarbazone Derivatives Present Antitumor Activity Mediated by Apoptosis and DNA Intercalation. Curr Top Med Chem 2019; 19:1075-1091. [PMID: 31223089 DOI: 10.2174/1568026619666190621120304] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/12/2019] [Accepted: 04/02/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Considering the need for the development of new antitumor drugs, associated with the great antitumor potential of thiophene and thiosemicarbazonic derivatives, in this work we promote molecular hybridization approach to synthesize new compounds with increased anticancer activity. OBJECTIVE Investigate the antitumor activity and their likely mechanisms of action of a series of N-substituted 2-(5-nitro-thiophene)-thiosemicarbazone derivatives. METHODS Methods were performed in vitro (cytotoxicity, cell cycle progression, morphological analysis, mitochondrial membrane potential evaluation and topoisomerase assay), spectroscopic (DNA interaction studies), and in silico studies (docking and molecular modelling). RESULTS Most of the compounds presented significant inhibitory activity; the NCIH-292 cell line was the most resistant, and the HL-60 cell line was the most sensitive. The most promising compound was LNN-05 with IC50 values ranging from 0.5 to 1.9 µg.mL-1. The in vitro studies revealed that LNN-05 was able to depolarize (dose-dependently) the mitochondrial membrane, induceG1 phase cell cycle arrest noticeably, promote morphological cell changes associated with apoptosis in chronic human myelocytic leukaemia (K-562) cells, and presented no topoisomerase II inhibition. Spectroscopic UV-vis and molecular fluorescence studies showed that LNN compounds interact with ctDNA forming supramolecular complexes. Intercalation between nitrogenous bases was revealed through KI quenching and competitive ethidium bromide assays. Docking and Molecular Dynamics suggested that 5-nitro-thiophene-thiosemicarbazone compounds interact against the larger DNA groove, and corroborating the spectroscopic results, may assume an intercalating interaction mode. CONCLUSION Our findings highlight 5-nitro-thiophene-thiosemicarbazone derivatives, especially LNN-05, as a promising new class of compounds for further studies to provide new anticancer therapies.
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Affiliation(s)
- Karla Mirella Roque Marques
- Bioactive Products Prospecting Laboratory, Department of Antibiotics, Federal University of Pernambuco, Recife-PE, Brazil
| | - Maria Rodrigues do Desterro
- Bioactive Products Prospecting Laboratory, Department of Antibiotics, Federal University of Pernambuco, Recife-PE, Brazil
| | - Sandrine Maria de Arruda
- Bioactive Products Prospecting Laboratory, Department of Antibiotics, Federal University of Pernambuco, Recife-PE, Brazil
| | - Luiz Nascimento de Araújo Neto
- Laboratory of Chemistry and Therapeutic Innovation, Department of Antibiotics, Federal University of Pernambuco, Recife-PE, Brazil
| | - Maria do Carmo Alves de Lima
- Laboratory of Chemistry and Therapeutic Innovation, Department of Antibiotics, Federal University of Pernambuco, Recife-PE, Brazil
| | | | - Edjan Carlos Dantas da Silva
- Laboratory of Medicinal Chemistry, Nursing and Pharmacy School, Federal University of Alagoas, Maceio-AL, Brazil
| | - Thiago Mendonça de Aquino
- Laboratory of Medicinal Chemistry, Nursing and Pharmacy School, Federal University of Alagoas, Maceio-AL, Brazil
| | | | - João Xavier de Araújo-Júnior
- Laboratory of Medicinal Chemistry, Nursing and Pharmacy School, Federal University of Alagoas, Maceio-AL, Brazil
| | - Marina de M Silva
- Laboratory of Development and Instrumentation in Analytical Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Maceio-AL, Brazil
| | - Maria Dayanne de A Dantas
- Laboratory of Development and Instrumentation in Analytical Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Maceio-AL, Brazil
| | - Josué Carinhanha C Santos
- Laboratory of Development and Instrumentation in Analytical Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Maceio-AL, Brazil
| | - Isis M Figueiredo
- Laboratory of Development and Instrumentation in Analytical Chemistry, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Maceio-AL, Brazil
| | - Marc-Antoine Bazin
- Universite de Nantes, Cibles et medicaments des infections et du cancer, IICiMed, EA1155, F-44000 Nantes, France
| | - Pascal Marchand
- Universite de Nantes, Cibles et medicaments des infections et du cancer, IICiMed, EA1155, F-44000 Nantes, France
| | - Teresinha Gonçalves da Silva
- Bioactive Products Prospecting Laboratory, Department of Antibiotics, Federal University of Pernambuco, Recife-PE, Brazil
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Wideman JG, Novick A, Muñoz-Gómez SA, Doolittle WF. Neutral evolution of cellular phenotypes. Curr Opin Genet Dev 2019; 58-59:87-94. [PMID: 31574422 DOI: 10.1016/j.gde.2019.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/29/2022]
Abstract
Eukaryotes exhibit a great diversity of cellular and subcellular morphologies, but their basic underlying architecture is fairly constant. All have a nucleus, Golgi, cytoskeleton, plasma membrane, vesicles, ribosomes, and all known lineages but one have mitochondrion-related organelles. Moreover, most eukaryotes undergo processes such as mitosis, meiosis, DNA recombination, and often perform feats such as phagocytosis, and amoeboid and flagellar movement. With all of these commonalities, it is obvious that eukaryotes evolved from a common ancestor, but it is not obvious how eukaryotes came to have their diverse structural phenotypes. Are these phenotypes adaptations to particular niches, their evolution dominated by positive natural selection? Or is eukaryotic cellular diversity substantially the product of neutral evolutionary processes, with adaptation either illusory or a secondary consequence? In this paper, we outline how a hierarchical view of phenotype can be used to articulate a neutral theory of phenotypic evolution, involving processes such as gene loss, gene replacement by homologues or analogues, gene duplication followed by subfunctionalization, and constructive neutral evolution. We suggest that neutral iterations of these processes followed by entrenchment of their products can explain much of the diversity of cellular, developmental, and biochemical phenotypes of unicellular eukaryotes and should be explored in addition to adaptive explanations.
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Affiliation(s)
- Jeremy G Wideman
- Centre for Mechanisms of Evolution, Arizona State University, Tempe, AZ, 85287, USA; Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Aaron Novick
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada; Department of Philosophy, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada; Department of Philosophy, Purdue University, West Lafayette, IN, 47907, USA
| | - Sergio A Muñoz-Gómez
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - W Ford Doolittle
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
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Steenwyk JL, Opulente DA, Kominek J, Shen XX, Zhou X, Labella AL, Bradley NP, Eichman BF, Čadež N, Libkind D, DeVirgilio J, Hulfachor AB, Kurtzman CP, Hittinger CT, Rokas A. Extensive loss of cell-cycle and DNA repair genes in an ancient lineage of bipolar budding yeasts. PLoS Biol 2019; 17:e3000255. [PMID: 31112549 PMCID: PMC6528967 DOI: 10.1371/journal.pbio.3000255] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 04/18/2019] [Indexed: 02/06/2023] Open
Abstract
Cell-cycle checkpoints and DNA repair processes protect organisms from potentially lethal mutational damage. Compared to other budding yeasts in the subphylum Saccharomycotina, we noticed that a lineage in the genus Hanseniaspora exhibited very high evolutionary rates, low Guanine-Cytosine (GC) content, small genome sizes, and lower gene numbers. To better understand Hanseniaspora evolution, we analyzed 25 genomes, including 11 newly sequenced, representing 18/21 known species in the genus. Our phylogenomic analyses identify two Hanseniaspora lineages, a faster-evolving lineage (FEL), which began diversifying approximately 87 million years ago (mya), and a slower-evolving lineage (SEL), which began diversifying approximately 54 mya. Remarkably, both lineages lost genes associated with the cell cycle and genome integrity, but these losses were greater in the FEL. E.g., all species lost the cell-cycle regulator WHIskey 5 (WHI5), and the FEL lost components of the spindle checkpoint pathway (e.g., Mitotic Arrest-Deficient 1 [MAD1], Mitotic Arrest-Deficient 2 [MAD2]) and DNA-damage-checkpoint pathway (e.g., Mitosis Entry Checkpoint 3 [MEC3], RADiation sensitive 9 [RAD9]). Similarly, both lineages lost genes involved in DNA repair pathways, including the DNA glycosylase gene 3-MethylAdenine DNA Glycosylase 1 (MAG1), which is part of the base-excision repair pathway, and the DNA photolyase gene PHotoreactivation Repair deficient 1 (PHR1), which is involved in pyrimidine dimer repair. Strikingly, the FEL lost 33 additional genes, including polymerases (i.e., POLymerase 4 [POL4] and POL32) and telomere-associated genes (e.g., Repressor/activator site binding protein-Interacting Factor 1 [RIF1], Replication Factor A 3 [RFA3], Cell Division Cycle 13 [CDC13], Pbp1p Binding Protein [PBP2]). Echoing these losses, molecular evolutionary analyses reveal that, compared to the SEL, the FEL stem lineage underwent a burst of accelerated evolution, which resulted in greater mutational loads, homopolymer instabilities, and higher fractions of mutations associated with the common endogenously damaged base, 8-oxoguanine. We conclude that Hanseniaspora is an ancient lineage that has diversified and thrived, despite lacking many otherwise highly conserved cell-cycle and genome integrity genes and pathways, and may represent a novel, to our knowledge, system for studying cellular life without them.
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Affiliation(s)
- Jacob L Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Dana A Opulente
- Laboratory of Genetics, Genome Center of Wisconsin, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Wisconsin, United States of America
| | - Jacek Kominek
- Laboratory of Genetics, Genome Center of Wisconsin, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Wisconsin, United States of America
| | - Xing-Xing Shen
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Xiaofan Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Abigail L Labella
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Noah P Bradley
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Neža Čadež
- University of Ljubljana Biotechnical Faculty, Department of Food Science and Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Diego Libkind
- Laboratorio de Microbiología Aplicada, Biotecnología y Bioinformática, Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales, Universidad Nacional del Comahue-CONICET, San Carlos de Bariloche, Río Negro, Argentina
| | - Jeremy DeVirgilio
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, Illinois, United States of America
| | - Amanda Beth Hulfachor
- Laboratory of Genetics, Genome Center of Wisconsin, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Cletus P Kurtzman
- Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, Illinois, United States of America
| | - Chris Todd Hittinger
- Laboratory of Genetics, Genome Center of Wisconsin, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Wisconsin, United States of America
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
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Topacio BR, Zatulovskiy E, Cristea S, Xie S, Tambo CS, Rubin SM, Sage J, Kõivomägi M, Skotheim JM. Cyclin D-Cdk4,6 Drives Cell-Cycle Progression via the Retinoblastoma Protein's C-Terminal Helix. Mol Cell 2019; 74:758-770.e4. [PMID: 30982746 PMCID: PMC6800134 DOI: 10.1016/j.molcel.2019.03.020] [Citation(s) in RCA: 160] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 02/01/2019] [Accepted: 03/19/2019] [Indexed: 01/10/2023]
Abstract
The cyclin-dependent kinases Cdk4 and Cdk6 form complexes with D-type cyclins to drive cell proliferation. A well-known target of cyclin D-Cdk4,6 is the retinoblastoma protein Rb, which inhibits cell-cycle progression until its inactivation by phosphorylation. However, the role of Rb phosphorylation by cyclin D-Cdk4,6 in cell-cycle progression is unclear because Rb can be phosphorylated by other cyclin-Cdks, and cyclin D-Cdk4,6 has other targets involved in cell division. Here, we show that cyclin D-Cdk4,6 docks one side of an alpha-helix in the Rb C terminus, which is not recognized by cyclins E, A, and B. This helix-based docking mechanism is shared by the p107 and p130 Rb-family members across metazoans. Mutation of the Rb C-terminal helix prevents its phosphorylation, promotes G1 arrest, and enhances Rb's tumor suppressive function. Our work conclusively demonstrates that the cyclin D-Rb interaction drives cell division and expands the diversity of known cyclin-based protein docking mechanisms.
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Affiliation(s)
| | | | - Sandra Cristea
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shicong Xie
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Carrie S Tambo
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Julien Sage
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mardo Kõivomägi
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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White MW, Suvorova ES. Apicomplexa Cell Cycles: Something Old, Borrowed, Lost, and New. Trends Parasitol 2018; 34:759-771. [PMID: 30078701 PMCID: PMC6157590 DOI: 10.1016/j.pt.2018.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 02/04/2023]
Abstract
Increased parasite burden is linked to the severity of clinical disease caused by Apicomplexa parasites such as Toxoplasma gondii, Plasmodium spp, and Cryptosporidium. Pathogenesis of apicomplexan infections is greatly affected by the growth rate of the parasite asexual stages. This review discusses recent advances in deciphering the mitotic structures and cell cycle regulatory factors required by Apicomplexa parasites to replicate. As the molecular details become clearer, it is evident that the highly unconventional cell cycles of these parasites is a blending of many ancient and borrowed elements, which were then adapted to enable apicomplexan proliferation in a wide variety of different animal hosts.
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Affiliation(s)
- Michael W White
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Elena S Suvorova
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA.
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35
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Hendler A, Medina EM, Buchler NE, de Bruin RAM, Aharoni A. The evolution of a G1/S transcriptional network in yeasts. Curr Genet 2018; 64:81-86. [PMID: 28744706 DOI: 10.1007/s00294-017-0726-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 07/11/2017] [Accepted: 07/17/2017] [Indexed: 11/28/2022]
Abstract
The G1-to-S cell cycle transition is promoted by the periodic expression of a large set of genes. In Saccharomyces cerevisiae G1/S gene expression is regulated by two transcription factor (TF) complexes, the MBF and SBF, which bind to specific DNA sequences, the MCB and SCB, respectively. Despite extensive research little is known regarding the evolution of the G1/S transcription regulation including the co-evolution of the DNA binding domains with their respective DNA binding sequences. We have recently examined the co-evolution of the G1/S TF specificity through the systematic generation and examination of chimeric Mbp1/Swi4 TFs containing different orthologue DNA binding domains in S. cerevisiae (Hendler et al. in PLoS Genet 13:e1006778. doi: 10.1371/journal.pgen.1006778 , 2017). Here, we review the co-evolution of G1/S transcriptional network and discuss the evolutionary dynamics and specificity of the MBF-MCB and SBF-SCB interactions in different fungal species.
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Affiliation(s)
- Adi Hendler
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, 84105, Beersheba, Israel
| | - Edgar M Medina
- Department of Biology, Duke University, Durham, NC, USA
- Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Nicolas E Buchler
- Department of Biology, Duke University, Durham, NC, USA.
- Center for Genomic and Computational Biology, Duke University, Durham, NC, USA.
| | - Robertus A M de Bruin
- MRC Laboratory for Molecular Cell Biology, University College London, London, WC1E 6BT, UK.
| | - Amir Aharoni
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, 84105, Beersheba, Israel.
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Hanson SJ, Byrne KP, Wolfe KH. Flip/flop mating-type switching in the methylotrophic yeast Ogataea polymorpha is regulated by an Efg1-Rme1-Ste12 pathway. PLoS Genet 2017; 13:e1007092. [PMID: 29176810 PMCID: PMC5720833 DOI: 10.1371/journal.pgen.1007092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 12/07/2017] [Accepted: 10/31/2017] [Indexed: 01/01/2023] Open
Abstract
In haploid cells of Ogataea (Hansenula) polymorpha an environmental signal, nitrogen starvation, induces a reversible change in the structure of a chromosome. This process, mating-type switching, inverts a 19-kb DNA region to place either MATa or MATα genes under centromeric repression of transcription, depending on the orientation of the region. Here, we investigated the genetic pathway that controls switching. We characterized the transcriptomes of haploid and diploid O. polymorpha by RNAseq in rich and nitrogen-deficient media, and found that there are no constitutively a-specific or α-specific genes other than the MAT genes themselves. We mapped a switching defect in a sibling species (O. parapolymorpha strain DL-1) by interspecies bulk segregant analysis to a frameshift in the transcription factor EFG1, which in Candida albicans regulates filamentous growth and white-opaque switching. Gene knockout, overexpression and ChIPseq experiments show that EFG1 regulates RME1, which in turn regulates STE12, to achieve mating-type switching. All three genes are necessary both for switching and for mating. Overexpression of RME1 or STE12 is sufficient to induce switching without a nitrogen depletion signal. The homologous recombination genes RAD51 and RAD17 are also necessary for switching. The pathway controlling switching in O. polymorpha shares no components with the regulation of HO in S. cerevisiae, which does not involve any environmental signal, but it shares some components with mating-type switching in Kluyveromyces lactis and with white-opaque phenotypic switching in C. albicans. The molecular mechanisms of self-fertility (homothallism) vary enormously among fungal species. We previously found that in the yeast Ogataea polymorpha, homothallism is achieved by a novel mating-type switching mechanism that exchanges the locations of MATa and MATα genes between expression and repression contexts. Switching in this species is induced by nitrogen depletion, unlike the analogous process in Saccharomyces cerevisiae. Here, we show that the upstream parts of the genetic pathway controlling the environmental induction of switching in O. polymorpha are the same as the environmental pathway that induces competence for mating in this species.
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Affiliation(s)
- Sara J. Hanson
- UCD Conway Institute, School of Medicine, University College Dublin, Dublin 4, Ireland
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado, United States of America
- * E-mail:
| | - Kevin P. Byrne
- UCD Conway Institute, School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Kenneth H. Wolfe
- UCD Conway Institute, School of Medicine, University College Dublin, Dublin 4, Ireland
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Abstract
In many contexts, the problem arises of determining which of many candidate mutations is the most likely to be causative for some phenotype. It is desirable to have a way to evaluate this probability that relies as little as possible on previous knowledge, to avoid bias against discovering new genes or functions. We have isolated mutants with blocked cell cycle progression in Chlamydomonas and determined mutant genome sequences. Due to the intensity of UV mutagenesis required for efficient mutant collection, the mutants contain multiple mutations altering coding sequence. To provide a quantitative estimate of probability that each individual mutation in a given mutant is the causative one, we developed a Bayesian approach. The approach employs four independent indicators: sequence conservation of the mutated coding sequence with Arabidopsis; severity of the mutation relative to Chlamydomonas wild-type based on Blosum62 scores; meiotic mapping information for location of the causative mutation relative to known molecular markers; and, for a subset of mutants, the transcriptional profile of the candidate wild-type genes through the mitotic cell cycle. These indicators are statistically independent, and so can be combined quantitatively into a single probability calculation. We validate this calculation: recently isolated mutations that were not in the training set for developing the indicators, with high calculated probability of causality, are confirmed in every case by additional genetic data to indeed be causative. Analysis of “best reciprocal BLAST” (BRB) relationships among Chlamydomonas and other eukaryotes indicate that the temperature sensitive-lethal (Ts-lethal) mutants that our procedure recovers are highly enriched for fundamental cell-essential functions conserved broadly across plants and other eukaryotes, accounting for the high information content of sequence alignment to Arabidopsis.
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Liban TJ, Medina EM, Tripathi S, Sengupta S, Henry RW, Buchler NE, Rubin SM. Conservation and divergence of C-terminal domain structure in the retinoblastoma protein family. Proc Natl Acad Sci U S A 2017; 114:4942-4947. [PMID: 28439018 PMCID: PMC5441720 DOI: 10.1073/pnas.1619170114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The retinoblastoma protein (Rb) and the homologous pocket proteins p107 and p130 negatively regulate cell proliferation by binding and inhibiting members of the E2F transcription factor family. The structural features that distinguish Rb from other pocket proteins have been unclear but are critical for understanding their functional diversity and determining why Rb has unique tumor suppressor activities. We describe here important differences in how the Rb and p107 C-terminal domains (CTDs) associate with the coiled-coil and marked-box domains (CMs) of E2Fs. We find that although CTD-CM binding is conserved across protein families, Rb and p107 CTDs show clear preferences for different E2Fs. A crystal structure of the p107 CTD bound to E2F5 and its dimer partner DP1 reveals the molecular basis for pocket protein-E2F binding specificity and how cyclin-dependent kinases differentially regulate pocket proteins through CTD phosphorylation. Our structural and biochemical data together with phylogenetic analyses of Rb and E2F proteins support the conclusion that Rb evolved specific structural motifs that confer its unique capacity to bind with high affinity those E2Fs that are the most potent activators of the cell cycle.
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Affiliation(s)
- Tyler J Liban
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064
| | - Edgar M Medina
- Department of Biology, Duke University, Durham, NC 27708
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708
| | - Sarvind Tripathi
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064
| | - Satyaki Sengupta
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - R William Henry
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824
| | - Nicolas E Buchler
- Department of Biology, Duke University, Durham, NC 27708
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064;
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Hendler A, Medina EM, Kishkevich A, Abu-Qarn M, Klier S, Buchler NE, de Bruin RAM, Aharoni A. Gene duplication and co-evolution of G1/S transcription factor specificity in fungi are essential for optimizing cell fitness. PLoS Genet 2017; 13:e1006778. [PMID: 28505153 PMCID: PMC5448814 DOI: 10.1371/journal.pgen.1006778] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 05/30/2017] [Accepted: 04/24/2017] [Indexed: 01/21/2023] Open
Abstract
Transcriptional regulatory networks play a central role in optimizing cell survival. How DNA binding domains and cis-regulatory DNA binding sequences have co-evolved to allow the expansion of transcriptional networks and how this contributes to cellular fitness remains unclear. Here we experimentally explore how the complex G1/S transcriptional network evolved in the budding yeast Saccharomyces cerevisiae by examining different chimeric transcription factor (TF) complexes. Over 200 G1/S genes are regulated by either one of the two TF complexes, SBF and MBF, which bind to specific DNA binding sequences, SCB and MCB, respectively. The difference in size and complexity of the G1/S transcriptional network across yeast species makes it well suited to investigate how TF paralogs (SBF and MBF) and DNA binding sequences (SCB and MCB) co-evolved after gene duplication to rewire and expand the network of G1/S target genes. Our data suggests that whilst SBF is the likely ancestral regulatory complex, the ancestral DNA binding element is more MCB-like. G1/S network expansion took place by both cis- and trans- co-evolutionary changes in closely related but distinct regulatory sequences. Replacement of the endogenous SBF DNA-binding domain (DBD) with that from more distantly related fungi leads to a contraction of the SBF-regulated G1/S network in budding yeast, which also correlates with increased defects in cell growth, cell size, and proliferation.
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Affiliation(s)
- Adi Hendler
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Edgar M. Medina
- Department of Biology, Duke University, Durham, United States
- Center for Genomic and Computational Biology, Duke University, Durham, United States
| | - Anastasiya Kishkevich
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Mehtap Abu-Qarn
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Steffi Klier
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Nicolas E. Buchler
- Department of Biology, Duke University, Durham, United States
- Center for Genomic and Computational Biology, Duke University, Durham, United States
| | - Robertus A. M. de Bruin
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Amir Aharoni
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be’er Sheva, Israel
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Kelliher CM, Haase SB. Connecting virulence pathways to cell-cycle progression in the fungal pathogen Cryptococcus neoformans. Curr Genet 2017; 63:803-811. [PMID: 28265742 PMCID: PMC5605583 DOI: 10.1007/s00294-017-0688-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 11/01/2022]
Abstract
Proliferation and host evasion are critical processes to understand at a basic biological level for improving infectious disease treatment options. The human fungal pathogen Cryptococcus neoformans causes fungal meningitis in immunocompromised individuals by proliferating in cerebrospinal fluid. Current antifungal drugs target "virulence factors" for disease, such as components of the cell wall and polysaccharide capsule in C. neoformans. However, mechanistic links between virulence pathways and the cell cycle are not as well studied. Recently, cell-cycle synchronized C. neoformans cells were profiled over time to identify gene expression dynamics (Kelliher et al., PLoS Genet 12(12):e1006453, 2016). Almost 20% of all genes in the C. neoformans genome were periodically activated during the cell cycle in rich media, including 40 genes that have previously been implicated in virulence pathways. Here, we review important findings about cell-cycle-regulated genes in C. neoformans and provide two examples of virulence pathways-chitin synthesis and G-protein coupled receptor signaling-with their putative connections to cell division. We propose that a "comparative functional genomics" approach, leveraging gene expression timing during the cell cycle, orthology to genes in other fungal species, and previous experimental findings, can lead to mechanistic hypotheses connecting the cell cycle to fungal virulence.
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Affiliation(s)
- Christina M Kelliher
- Department of Biology, Duke University, Box 90338, 130 Science Drive, Durham, NC, 27708-0338, USA
| | - Steven B Haase
- Department of Biology, Duke University, Box 90338, 130 Science Drive, Durham, NC, 27708-0338, USA.
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Investigating Conservation of the Cell-Cycle-Regulated Transcriptional Program in the Fungal Pathogen, Cryptococcus neoformans. PLoS Genet 2016; 12:e1006453. [PMID: 27918582 PMCID: PMC5137879 DOI: 10.1371/journal.pgen.1006453] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/01/2016] [Indexed: 12/24/2022] Open
Abstract
The pathogenic yeast Cryptococcus neoformans causes fungal meningitis in immune-compromised patients. Cell proliferation in the budding yeast form is required for C. neoformans to infect human hosts, and virulence factors such as capsule formation and melanin production are affected by cell-cycle perturbation. Thus, understanding cell-cycle regulation is critical for a full understanding of virulence factors for disease. Our group and others have demonstrated that a large fraction of genes in Saccharomyces cerevisiae is expressed periodically during the cell cycle, and that proper regulation of this transcriptional program is important for proper cell division. Despite the evolutionary divergence of the two budding yeasts, we found that a similar percentage of all genes (~20%) is periodically expressed during the cell cycle in both yeasts. However, the temporal ordering of periodic expression has diverged for some orthologous cell-cycle genes, especially those related to bud emergence and bud growth. Genes regulating DNA replication and mitosis exhibited a conserved ordering in both yeasts, suggesting that essential cell-cycle processes are conserved in periodicity and in timing of expression (i.e. duplication before division). In S. cerevisiae cells, we have proposed that an interconnected network of periodic transcription factors (TFs) controls the bulk of the cell-cycle transcriptional program. We found that temporal ordering of orthologous network TFs was not always maintained; however, the TF network topology at cell-cycle commitment appears to be conserved in C. neoformans. During the C. neoformans cell cycle, DNA replication genes, mitosis genes, and 40 genes involved in virulence are periodically expressed. Future work toward understanding the gene regulatory network that controls cell-cycle genes is critical for developing novel antifungals to inhibit pathogen proliferation.
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Abstract
How and when eukaryotic cells make the irrevocable commitment to divide remain central questions in the cell-cycle field. Parallel studies in yeast and mammalian cells seemed to suggest analogous control mechanisms operating during the G1 phase—at Start or the restriction (R) point, respectively—to integrate nutritional and developmental signals and decide between distinct cell fates: cell-cycle arrest or exit versus irreversible commitment to a round of division. Recent work has revealed molecular mechanisms underlying this decision-making process in both yeast and mammalian cells but also cast doubt on the nature and timing of cell-cycle commitment in multicellular organisms. These studies suggest an expanded temporal window of mitogen sensing under certain growth conditions, illuminate unexpected obstacles and exit ramps on the path to full cell-cycle commitment, and raise new questions regarding the functions of cyclin-dependent kinases (CDKs) that drive G1 progression and S-phase entry.
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Affiliation(s)
- Robert P Fisher
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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