101
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Kaur H, Ahuja JS, Lichten M. Methods for Controlled Protein Depletion to Study Protein Function during Meiosis. Methods Enzymol 2018; 601:331-357. [PMID: 29523238 PMCID: PMC10798147 DOI: 10.1016/bs.mie.2017.11.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Proteins with potential roles in meiotic recombination often have essential or important functions during the mitotic cell cycle. In addition, proteins may have different functions at different times during meiosis. In such cases, it can be challenging to precisely determine protein function during meiosis using null or hypomorphic mutants. One example is the Sgs1-Top3-Rmi1 helicase-decatenase complex, which is required for normal vegetative growth and genome stability. In such cases, conditional loss-of-function mutants can be useful. In this chapter, we describe the construction of two types of conditional mutants, meiotic depletion alleles and auxin-induced degradation alleles, that allow protein depletion specifically during budding yeast meiosis, and illustrate their use with Sgs1. We also describe a modified method for the isolation of meiotic recombination intermediates that combines previous psoralen cross-linking and cetyltrimethylammonium bromide isolation methods.
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Affiliation(s)
- Hardeep Kaur
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States
| | - Jasvinder S Ahuja
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States
| | - Michael Lichten
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States.
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102
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Repression of Middle Sporulation Genes in Saccharomyces cerevisiae by the Sum1-Rfm1-Hst1 Complex Is Maintained by Set1 and H3K4 Methylation. G3-GENES GENOMES GENETICS 2017; 7:3971-3982. [PMID: 29066473 PMCID: PMC5714494 DOI: 10.1534/g3.117.300150] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The conserved yeast histone methyltransferase Set1 targets H3 lysine 4 (H3K4) for mono, di, and trimethylation and is linked to active transcription due to the euchromatic distribution of these methyl marks and the recruitment of Set1 during transcription. However, loss of Set1 results in increased expression of multiple classes of genes, including genes adjacent to telomeres and middle sporulation genes, which are repressed under normal growth conditions because they function in meiotic progression and spore formation. The mechanisms underlying Set1-mediated gene repression are varied, and still unclear in some cases, although repression has been linked to both direct and indirect action of Set1, associated with noncoding transcription, and is often dependent on the H3K4me2 mark. We show that Set1, and particularly the H3K4me2 mark, are implicated in repression of a subset of middle sporulation genes during vegetative growth. In the absence of Set1, there is loss of the DNA-binding transcriptional regulator Sum1 and the associated histone deacetylase Hst1 from chromatin in a locus-specific manner. This is linked to increased H4K5ac at these loci and aberrant middle gene expression. These data indicate that, in addition to DNA sequence, histone modification status also contributes to proper localization of Sum1 Our results also show that the role for Set1 in middle gene expression control diverges as cells receive signals to undergo meiosis. Overall, this work dissects an unexplored role for Set1 in gene-specific repression, and provides important insights into a new mechanism associated with the control of gene expression linked to meiotic differentiation.
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103
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Xu XX, Komatsuzaki A, Chiba Y, Gao XD, Yoko-O T. PER1, GUP1 and CWH43 of methylotrophic yeast Ogataea minuta are involved in cell wall integrity. Yeast 2017; 35:225-236. [PMID: 29027702 DOI: 10.1002/yea.3285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 09/25/2017] [Accepted: 10/03/2017] [Indexed: 12/23/2022] Open
Abstract
In eukaryotes, the glycosylphosphatidylinositol (GPI) modification of many glycoproteins on the cell surface is highly conserved. The lipid moieties of GPI-anchored proteins undergo remodelling processes during their maturation. To date, the products of the PER1, GUP1 and CWH43 genes of the yeast Saccharomyces cerevisiae have been shown to be involved in the lipid remodelling. Here, we focus on the putative GPI remodelling pathway in the methylotrophic yeast Ogataea minuta. We found that the O. minuta homologues of PER1, GUP1 and CWH43 are functionally compatible with those of S. cerevisiae. Disruption of GUP1 or CWH43 in O. minuta caused a growth defect under non-permissive conditions. The O. minuta per1Δ mutant exhibited a more fragile phenotype than the gup1Δ or cwh43Δ mutants. To address the role of GPI modification in O. minuta, we assessed the effect of these mutations on the processing and localization of the O. minuta homologues of the Gas1 protein; in S. cerevisiae, Gas1p is an abundant and well-characterized GPI-anchored protein. We found that O. minuta possesses two copies of the GAS1 gene, which we designate GAS1A and GAS1B. Microscopy and western blotting analysis showed mislocalization and/or lower retention of Gas1Ap and Gas1Bp within the membrane fraction in per1Δ or gup1Δ mutant cells, suggesting the significance of lipid remodelling for GPI-anchored proteins in O. minuta. Localization behaviour of Gas1Bp differed from that of Gas1Ap. Our data reveals, for the first time (to our knowledge), the existence of genes related to GPI anchor remodelling in O. minuta cells.
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Affiliation(s)
- Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China.,Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
| | - Akiko Komatsuzaki
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
| | - Yasunori Chiba
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Takehiko Yoko-O
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
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104
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Zhou S, Sternglanz R, Neiman AM. Developmentally regulated internal transcription initiation during meiosis in budding yeast. PLoS One 2017; 12:e0188001. [PMID: 29136644 PMCID: PMC5685637 DOI: 10.1371/journal.pone.0188001] [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: 08/16/2017] [Accepted: 10/30/2017] [Indexed: 02/07/2023] Open
Abstract
Sporulation of budding yeast is a developmental process in which cells undergo meiosis to generate stress-resistant progeny. The dynamic nature of the budding yeast meiotic transcriptome has been well established by a number of genome-wide studies. Here we develop an analysis pipeline to systematically identify novel transcription start sites that reside internal to a gene. Application of this pipeline to data from a synchronized meiotic time course reveals over 40 genes that display specific internal initiations in mid-sporulation. Consistent with the time of induction, motif analysis on upstream sequences of these internal transcription start sites reveals a significant enrichment for the binding site of Ndt80, the transcriptional activator of middle sporulation genes. Further examination of one gene, MRK1, demonstrates the Ndt80 binding site is necessary for internal initiation and results in the expression of an N-terminally truncated protein isoform. When the MRK1 paralog RIM11 is downregulated, the MRK1 internal transcript promotes efficient sporulation, indicating functional significance of the internal initiation. Our findings suggest internal transcriptional initiation to be a dynamic, regulated process with potential functional impacts on development.
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Affiliation(s)
- Sai Zhou
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States of America
- Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, United States of America
| | - Rolf Sternglanz
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States of America
| | - Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States of America
- * E-mail:
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105
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Omerza G, Tio CW, Philips T, Diamond A, Neiman AM, Winter E. The meiosis-specific Cdc20 family-member Ama1 promotes binding of the Ssp2 activator to the Smk1 MAP kinase. Mol Biol Cell 2017; 29:66-74. [PMID: 29118076 PMCID: PMC5746067 DOI: 10.1091/mbc.e17-07-0473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/27/2017] [Accepted: 10/31/2017] [Indexed: 02/02/2023] Open
Abstract
Smk1 is a meiosis-specific MAP kinase that is activated by a binding partner, Ssp2. This study shows that the meiosis-specific Cdc20 homologue, Ama1, triggers Ssp2/Smk1 complex formation at specialized meiotic membranes as nuclear segregation is being completed, thus triggering kinase activity at a specific place and time during this developmental program. Smk1 is a meiosis-specific MAP kinase (MAPK) in budding yeast that is required for spore formation. It is localized to prospore membranes (PSMs), the structures that engulf haploid cells during meiosis II (MII). Similar to canonically activated MAPKs, Smk1 is controlled by phosphorylation of its activation-loop threonine (T) and tyrosine (Y). However, activation loop phosphorylation occurs via a noncanonical two-step mechanism in which 1) the cyclin-dependent kinase activating kinase Cak1 phosphorylaytes T207 during MI, and 2) Smk1 autophosphorylates Y209 as MII draws to a close. Autophosphorylation of Y209 and catalytic activity for substrates require Ssp2, a meiosis-specific protein that is translationally repressed until anaphase of MII. Ama1 is a meiosis-specific targeting subunit of the anaphase-promoting complex/cyclosome that regulates multiple steps in meiotic development, including exit from MII. Here, we show that Ama1 activates autophosphorylation of Smk1 on Y209 by promoting formation of the Ssp2/Smk1 complex at PSMs. These findings link meiotic exit to Smk1 activation and spore wall assembly.
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Affiliation(s)
- Gregory Omerza
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107
| | - Chong Wai Tio
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107
| | - Timothy Philips
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107
| | - Aviva Diamond
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794
| | - Aaron M Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794
| | - Edward Winter
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107
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106
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Bunina D, Štefl M, Huber F, Khmelinskii A, Meurer M, Barry JD, Kats I, Kirrmaier D, Huber W, Knop M. Upregulation of SPS100 gene expression by an antisense RNA via a switch of mRNA isoforms with different stabilities. Nucleic Acids Res 2017; 45:11144-11158. [PMID: 28977638 PMCID: PMC5737743 DOI: 10.1093/nar/gkx737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/09/2017] [Accepted: 08/21/2017] [Indexed: 12/19/2022] Open
Abstract
Pervasive transcription of genomes generates multiple classes of non-coding RNAs. One of these classes are stable long non-coding RNAs which overlap coding genes in antisense direction (asRNAs). The function of such asRNAs is not fully understood but several cases of antisense-dependent gene expression regulation affecting the overlapping genes have been demonstrated. Using high-throughput yeast genetics and a limited set of four growth conditions we previously reported a regulatory function for ∼25% of asRNAs, most of which repress the expression of the sense gene. To further explore the roles of asRNAs we tested more conditions and identified 15 conditionally antisense-regulated genes, 6 of which exhibited antisense-dependent enhancement of gene expression. We focused on the sporulation-specific gene SPS100, which becomes upregulated upon entry into starvation or sporulation as a function of the antisense transcript SUT169. We demonstrate that the antisense effect is mediated by its 3' intergenic region (3'-IGR) and that this regulation can be transferred to other genes. Genetic analysis revealed that SUT169 functions by changing the relative expression of SPS100 mRNA isoforms from a short and unstable transcript to a long and stable species. These results suggest a novel mechanism of antisense-dependent gene regulation via mRNA isoform switching.
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Affiliation(s)
- Daria Bunina
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Martin Štefl
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Florian Huber
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Anton Khmelinskii
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Matthias Meurer
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Joseph D. Barry
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Ilia Kats
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Daniel Kirrmaier
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
- Deutsches Krebsforschungszentrum (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Wolfgang Huber
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Michael Knop
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
- Deutsches Krebsforschungszentrum (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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107
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Exiting prophase I: no clear boundary. Curr Genet 2017; 64:423-427. [PMID: 29071381 DOI: 10.1007/s00294-017-0771-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 10/17/2017] [Accepted: 10/20/2017] [Indexed: 12/18/2022]
Abstract
The meiotic cell cycle provides a unique model to study the relationship between recombinational DNA repair and the cell cycle, since homologous recombination, induced by programmed DNA double-strand breaks (DSBs), is integrated as an essential step during meiosis. The pachytene checkpoint, which is situated towards the end of meiotic prophase I, coordinates homologous recombination and cell cycle progression, similar to the DNA damage checkpoint mechanisms operating in vegetative cells. However, there are a number of features unique to meiosis, making the system optimized for the purpose of meiosis. Our recent work highlights the involvement of three major cell cycle kinases, Dbf4-dependent Cdc7 kinase, Polo kinase and CDK, in coordinating homologous recombination and the meiotic cell cycle. In this review, we will discuss the unique interplay between meiotic cell cycle control and homologous recombination during meiosis I.
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108
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Chia M, Tresenrider A, Chen J, Spedale G, Jorgensen V, Ünal E, van Werven FJ. Transcription of a 5' extended mRNA isoform directs dynamic chromatin changes and interference of a downstream promoter. eLife 2017; 6:e27420. [PMID: 28906248 PMCID: PMC5655139 DOI: 10.7554/elife.27420] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/13/2017] [Indexed: 12/16/2022] Open
Abstract
Cell differentiation programs require dynamic regulation of gene expression. During meiotic prophase in Saccharomyces cerevisiae, expression of the kinetochore complex subunit Ndc80 is downregulated by a 5' extended long undecoded NDC80 transcript isoform. Here we demonstrate a transcriptional interference mechanism that is responsible for inhibiting expression of the coding NDC80 mRNA isoform. Transcription from a distal NDC80 promoter directs Set1-dependent histone H3K4 dimethylation and Set2-dependent H3K36 trimethylation to establish a repressive chromatin state in the downstream canonical NDC80 promoter. As a consequence, NDC80 expression is repressed during meiotic prophase. The transcriptional mechanism described here is rapidly reversible, adaptable to fine-tune gene expression, and relies on Set2 and the Set3 histone deacetylase complex. Thus, expression of a 5' extended mRNA isoform causes transcriptional interference at the downstream promoter. We demonstrate that this is an effective mechanism to promote dynamic changes in gene expression during cell differentiation.
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Affiliation(s)
| | - Amy Tresenrider
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Jingxun Chen
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | | | - Victoria Jorgensen
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Elçin Ünal
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
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109
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Abstract
Regulation of gene expression by DNA-binding transcription factors is essential for proper control of growth and development in all organisms. In this study, we annotate and characterize growth and developmental phenotypes for transcription factor genes in the model filamentous fungus Neurospora crassa. We identified 312 transcription factor genes, corresponding to 3.2% of the protein coding genes in the genome. The largest class was the fungal-specific Zn2Cys6 (C6) binuclear cluster, with 135 members, followed by the highly conserved C2H2 zinc finger group, with 61 genes. Viable knockout mutants were produced for 273 genes, and complete growth and developmental phenotypic data are available for 242 strains, with 64% possessing at least one defect. The most prominent defect observed was in growth of basal hyphae (43% of mutants analyzed), followed by asexual sporulation (38%), and the various stages of sexual development (19%). Two growth or developmental defects were observed for 21% of the mutants, while 8% were defective in all three major phenotypes tested. Analysis of available mRNA expression data for a time course of sexual development revealed mutants with sexual phenotypes that correlate with transcription factor transcript abundance in wild type. Inspection of this data also implicated cryptic roles in sexual development for several cotranscribed transcription factor genes that do not produce a phenotype when mutated.
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110
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Argunhan B, Leung WK, Afshar N, Terentyev Y, Subramanian VV, Murayama Y, Hochwagen A, Iwasaki H, Tsubouchi T, Tsubouchi H. Fundamental cell cycle kinases collaborate to ensure timely destruction of the synaptonemal complex during meiosis. EMBO J 2017; 36:2488-2509. [PMID: 28694245 DOI: 10.15252/embj.201695895] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 01/07/2023] Open
Abstract
The synaptonemal complex (SC) is a proteinaceous macromolecular assembly that forms during meiotic prophase I and mediates adhesion of paired homologous chromosomes along their entire lengths. Although prompt disassembly of the SC during exit from prophase I is a landmark event of meiosis, the underlying mechanism regulating SC destruction has remained elusive. Here, we show that DDK (Dbf4-dependent Cdc7 kinase) is central to SC destruction. Upon exit from prophase I, Dbf4, the regulatory subunit of DDK, directly associates with and is phosphorylated by the Polo-like kinase Cdc5. In parallel, upregulated CDK1 activity also targets Dbf4. An enhanced Dbf4-Cdc5 interaction pronounced phosphorylation of Dbf4 and accelerated SC destruction, while reduced/abolished Dbf4 phosphorylation hampered destruction of SC proteins. SC destruction relieved meiotic inhibition of the ubiquitous recombinase Rad51, suggesting that the mitotic recombination machinery is reactivated following prophase I exit to repair any persisting meiotic DNA double-strand breaks. Taken together, we propose that the concerted action of DDK, Polo-like kinase, and CDK1 promotes efficient SC destruction at the end of prophase I to ensure faithful inheritance of the genome.
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Affiliation(s)
- Bilge Argunhan
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton, East Sussex, UK.,Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Wing-Kit Leung
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton, East Sussex, UK
| | - Negar Afshar
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton, East Sussex, UK.,Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Yaroslav Terentyev
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton, East Sussex, UK
| | | | - Yasuto Murayama
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | | | - Hiroshi Iwasaki
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Tomomi Tsubouchi
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton, East Sussex, UK .,National Institute for Basic Biology, Okazaki, Japan
| | - Hideo Tsubouchi
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton, East Sussex, UK .,National Institute for Basic Biology, Okazaki, Japan
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111
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Regulating the construction and demolition of the synaptonemal complex. Nat Struct Mol Biol 2017; 23:369-77. [PMID: 27142324 DOI: 10.1038/nsmb.3208] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/18/2016] [Indexed: 01/11/2023]
Abstract
The synaptonemal complex (SC) is a meiosis-specific scaffold that links homologous chromosomes from end to end during meiotic prophase and is required for the formation of meiotic crossovers. Assembly of SC components is regulated by a combination of associated nonstructural proteins and post-translational modifications, such as SUMOylation, which together coordinate the timing between homologous chromosome pairing, double-strand-break formation and recombination. In addition, transcriptional and translational control mechanisms ensure the timely disassembly of the SC after crossover resolution and before chromosome segregation at anaphase I.
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112
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The Mitotic Exit Network Regulates Spindle Pole Body Selection During Sporulation of Saccharomyces cerevisiae. Genetics 2017; 206:919-937. [PMID: 28450458 DOI: 10.1534/genetics.116.194522] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 04/11/2017] [Indexed: 01/11/2023] Open
Abstract
Age-based inheritance of centrosomes in eukaryotic cells is associated with faithful chromosome distribution in asymmetric cell divisions. During Saccharomyces cerevisiae ascospore formation, such an inheritance mechanism targets the yeast centrosome equivalents, the spindle pole bodies (SPBs) at meiosis II onset. Decreased nutrient availability causes initiation of spore formation at only the younger SPBs and their associated genomes. This mechanism ensures encapsulation of nonsister genomes, which preserves genetic diversity and provides a fitness advantage at the population level. Here, by usage of an enhanced system for sporulation-induced protein depletion, we demonstrate that the core mitotic exit network (MEN) is involved in age-based SPB selection. Moreover, efficient genome inheritance requires Dbf2/20-Mob1 during a late step in spore maturation. We provide evidence that the meiotic functions of the MEN are more complex than previously thought. In contrast to mitosis, completion of the meiotic divisions does not strictly rely on the MEN whereas its activity is required at different time points during spore development. This is reminiscent of vegetative MEN functions in spindle polarity establishment, mitotic exit, and cytokinesis. In summary, our investigation contributes to the understanding of age-based SPB inheritance during sporulation of S. cerevisiae and provides general insights on network plasticity in the context of a specialized developmental program. Moreover, the improved system for a developmental-specific tool to induce protein depletion will be useful in other biological contexts.
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113
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Predicted RNA Binding Proteins Pes4 and Mip6 Regulate mRNA Levels, Translation, and Localization during Sporulation in Budding Yeast. Mol Cell Biol 2017; 37:MCB.00408-16. [PMID: 28193845 DOI: 10.1128/mcb.00408-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 02/05/2017] [Indexed: 02/05/2023] Open
Abstract
In response to starvation, diploid cells of Saccharomyces cerevisiae undergo meiosis and form haploid spores, a process collectively referred to as sporulation. The differentiation into spores requires extensive changes in gene expression. The transcriptional activator Ndt80 is a central regulator of this process, which controls many genes essential for sporulation. Ndt80 induces ∼300 genes coordinately during meiotic prophase, but different mRNAs within the NDT80 regulon are translated at different times during sporulation. The protein kinase Ime2 and RNA binding protein Rim4 are general regulators of meiotic translational delay, but how differential timing of individual transcripts is achieved was not known. This report describes the characterization of two related NDT80-induced genes, PES4 and MIP6, encoding predicted RNA binding proteins. These genes are necessary to regulate the steady-state expression, translational timing, and localization of a set of mRNAs that are transcribed by NDT80 but not translated until the end of meiosis II. Mutations in the predicted RNA binding domains within PES4 alter the stability of target mRNAs. PES4 and MIP6 affect only a small portion of the NDT80 regulon, indicating that they act as modulators of the general Ime2/Rim4 pathway for specific transcripts.
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114
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High-Throughput Screening to Identify Regulators of Meiosis-Specific Gene Expression in Saccharomyces cerevisiae. Methods Mol Biol 2017. [PMID: 28349394 DOI: 10.1007/978-1-4939-6340-9_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Meiosis and gamete formation are processes that are essential for sexual reproduction in all eukaryotic organisms. Multiple intracellular and extracellular signals feed into pathways that converge on transcription factors that induce the expression of meiosis-specific genes. Once triggered the meiosis-specific gene expression program proceeds in a cascade that drives progress through the events of meiosis and gamete formation. Meiosis-specific gene expression is tightly controlled by a balance of positive and negative regulatory factors that respond to a plethora of signaling pathways. The budding yeast Saccharomyces cerevisiae has proven to be an outstanding model for the dissection of gametogenesis owing to the sophisticated genetic manipulations that can be performed with the cells. It is possible to use a variety selection and screening methods to identify genes and their functions. High-throughput screening technology has been developed to allow an array of all viable yeast gene deletion mutants to be screened for phenotypes and for regulators of gene expression. This chapter describes a protocol that has been used to screen a library of homozygous diploid yeast deletion strains to identify regulators of the meiosis-specific IME1 gene.
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115
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Genetic Approaches to Study Meiosis and Meiosis-Specific Gene Expression in Saccharomyces cerevisiae. Methods Mol Biol 2017. [PMID: 28349388 DOI: 10.1007/978-1-4939-6340-9_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The budding yeast Saccharomyces cerevisiae has a long history as a model organism for studies of meiosis and the cell cycle. The popularity of this yeast as a model is in large part due to the variety of genetic and cytological approaches that can be effectively performed with the cells. Cultures of the cells can be induced to synchronously progress through meiosis and sporulation allowing large-scale gene expression and biochemical studies to be performed. Additionally, the spore tetrads resulting from meiosis make it possible to characterize the haploid products of meiosis allowing investigation of meiotic recombination and chromosome segregation. Here we describe genetic methods for analysis progression of S. cerevisiae through meiosis and sporulation with an emphasis on strategies for the genetic analysis of regulators of meiosis-specific genes.
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116
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Nocedal I, Mancera E, Johnson AD. Gene regulatory network plasticity predates a switch in function of a conserved transcription regulator. eLife 2017; 6:e23250. [PMID: 28327289 PMCID: PMC5391208 DOI: 10.7554/elife.23250] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 03/21/2017] [Indexed: 12/15/2022] Open
Abstract
The rewiring of gene regulatory networks can generate phenotypic novelty. It remains an open question, however, how the large number of connections needed to form a novel network arise over evolutionary time. Here, we address this question using the network controlled by the fungal transcription regulator Ndt80. This conserved protein has undergone a dramatic switch in function-from an ancestral role regulating sporulation to a derived role regulating biofilm formation. This switch in function corresponded to a large-scale rewiring of the genes regulated by Ndt80. However, we demonstrate that the Ndt80-target gene connections were undergoing extensive rewiring prior to the switch in Ndt80's regulatory function. We propose that extensive drift in the Ndt80 regulon allowed for the exploration of alternative network structures without a loss of ancestral function, thereby facilitating the formation of a network with a new function.
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Affiliation(s)
- Isabel Nocedal
- Department of Microbiology and Immunology, University of California, San Francisco, United States
- Department of Biochemistry and Biophysics, University of California, San Francisco, United States
| | - Eugenio Mancera
- Department of Microbiology and Immunology, University of California, San Francisco, United States
- Department of Biochemistry and Biophysics, University of California, San Francisco, United States
| | - Alexander D Johnson
- Department of Microbiology and Immunology, University of California, San Francisco, United States
- Department of Biochemistry and Biophysics, University of California, San Francisco, United States
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117
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Becker E, Com E, Lavigne R, Guilleux MH, Evrard B, Pineau C, Primig M. The protein expression landscape of mitosis and meiosis in diploid budding yeast. J Proteomics 2017; 156:5-19. [DOI: 10.1016/j.jprot.2016.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/14/2016] [Accepted: 12/26/2016] [Indexed: 12/12/2022]
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118
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Coordination of Double Strand Break Repair and Meiotic Progression in Yeast by a Mek1-Ndt80 Negative Feedback Loop. Genetics 2017; 206:497-512. [PMID: 28249986 DOI: 10.1534/genetics.117.199703] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 02/25/2017] [Indexed: 11/18/2022] Open
Abstract
During meiosis, homologous chromosomes are physically connected by crossovers and sister chromatid cohesion. Interhomolog crossovers are generated by the highly regulated repair of programmed double strand breaks (DSBs). The meiosis-specific kinase Mek1 is critical for this regulation. Mek1 downregulates the mitotic recombinase Rad51, indirectly promoting interhomolog strand invasion by the meiosis-specific recombinase Dmc1. Mek1 also promotes the formation of crossovers that are distributed throughout the genome by interference and is the effector kinase for a meiosis-specific checkpoint that delays entry into Meiosis I until DSBs have been repaired. The target of this checkpoint is a meiosis-specific transcription factor, Ndt80, which is necessary to express the polo-like kinase CDC5 and the cyclin CLB1 thereby allowing completion of recombination and meiotic progression. This work shows that Mek1 and Ndt80 negatively feedback on each other such that when DSB levels are high, Ndt80 is inactive due to high levels of Mek1 activity. As DSBs are repaired, chromosomes synapse and Mek1 activity is reduced below a threshold that allows activation of Ndt80. Ndt80 transcription of CDC5 results in degradation of Red1, a meiosis-specific protein required for Mek1 activation, thereby abolishing Mek1 activity completely. Elimination of Mek1 kinase activity allows Rad51-mediated repair of any remaining DSBs. In this way, cells do not enter Meiosis I until recombination is complete and all DSBs are repaired.
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119
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Zhang R, Yuan H, Wang S, Ouyang Q, Chen Y, Hao N, Luo C. High-throughput single-cell analysis for the proteomic dynamics study of the yeast osmotic stress response. Sci Rep 2017; 7:42200. [PMID: 28181485 PMCID: PMC5299847 DOI: 10.1038/srep42200] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 01/06/2017] [Indexed: 11/22/2022] Open
Abstract
Motorized fluorescence microscopy combined with high-throughput microfluidic chips is a powerful method to obtain information about different biological processes in cell biology studies. Generally, to observe different strains under different environments, high-throughput microfluidic chips require complex preparatory work. In this study, we designed a novel and easily operated high-throughput microfluidic system to observe 96 different GFP-tagged yeast strains in one switchable culture condition or 24 different GFP-tagged yeast strains in four parallel switchable culture conditions. A multi-pipette is the only additional equipment required for high-throughput patterning of cells in the chip. Only eight connections are needed to control 96 conditions. Using these devices, the proteomic dynamics of the yeast stress response pathway were carefully studied based on single-cell data. A new method to characterize the proteomic dynamics using a single cell’s data is proposed and compared to previous methods, and the new technique should be useful for studying underlying control networks. Our method provides an easy and systematic way to study signaling pathways at the single-cell level.
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Affiliation(s)
- Rongfei Zhang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Haiyu Yuan
- The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China
| | - Shujing Wang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Qi Ouyang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Yong Chen
- Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris, France
| | - Nan Hao
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, California, USA
| | - Chunxiong Luo
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, China
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120
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Dayan IE, Arga KY, Ulgen KO. Multiomics Approach to Novel Therapeutic Targets for Cancer and Aging-Related Diseases: Role of Sld7 in Yeast Aging Network. ACTA ACUST UNITED AC 2017; 21:100-113. [DOI: 10.1089/omi.2016.0157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Irem E. Dayan
- Department of Chemical Engineering, Bogazici University, Istanbul, Turkey
| | | | - Kutlu O. Ulgen
- Department of Chemical Engineering, Bogazici University, Istanbul, Turkey
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121
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Bdf1 Bromodomains Are Essential for Meiosis and the Expression of Meiotic-Specific Genes. PLoS Genet 2017; 13:e1006541. [PMID: 28068333 PMCID: PMC5261807 DOI: 10.1371/journal.pgen.1006541] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 01/24/2017] [Accepted: 12/15/2016] [Indexed: 11/19/2022] Open
Abstract
Bromodomain and Extra-terminal motif (BET) proteins play a central role in transcription regulation and chromatin signalling pathways. They are present in unicellular eukaryotes and in this study, the role of the BET protein Bdf1 has been explored in Saccharomyces cerevisiae. Mutation of Bdf1 bromodomains revealed defects on both the formation of spores and the meiotic progression, blocking cells at the exit from prophase, before the first meiotic division. This phenotype is associated with a massive deregulation of the transcription of meiotic genes and Bdf1 bromodomains are required for appropriate expression of the key meiotic transcription factor NDT80 and almost all the Ndt80-inducible genes, including APC complex components. Bdf1 notably accumulates on the promoter of Ndt80 and its recruitment is dependent on Bdf1 bromodomains. In addition, the ectopic expression of NDT80 during meiosis partially bypasses this dependency. Finally, purification of Bdf1 partners identified two independent complexes with Bdf2 or the SWR complex, neither of which was required to complete sporulation. Taken together, our results unveil a new role for Bdf1 –working independently from its predominant protein partners Bdf2 and the SWR1 complex–as a regulator of meiosis-specific genes. Chromatin modifying proteins play a central role in transcription regulation and chromatin signalling. In this study we investigated the functional role of the bromodomains of the chromatin protein Bdf1 during yeast gametogenesis. Our results show that the bromodomains of Bdf1 are essential for meiotic progression and the formation of mature spores. Bdf1 bromodomains are required for the expression of key meiotic genes and the master regulator NDT80. Forced expression of NDT80 can partially rescue the formation of spores when Bdf1 bromodomains are mutated. The results presented here indicate that Bdf1 forms two exclusive complexes, with Bdf2 or with the SWR complex. However, none of these complexes are required for sporulation progression. To conclude, our findings suggest that Bdf1 is a new regulator of the meiotic transcription program and of the expression of the master regulator NDT80.
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122
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Kumar V, Chhabra JK, Kumar D. Grey Wolf Algorithm-Based Clustering Technique. JOURNAL OF INTELLIGENT SYSTEMS 2017. [DOI: 10.1515/jisys-2014-0137] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractThe main problem of classical clustering technique is that it is easily trapped in the local optima. An attempt has been made to solve this problem by proposing the grey wolf algorithm (GWA)-based clustering technique, called GWA clustering (GWAC), through this paper. The search capability of GWA is used to search the optimal cluster centers in the given feature space. The agent representation is used to encode the centers of clusters. The proposed GWAC technique is tested on both artificial and real-life data sets and compared to six well-known metaheuristic-based clustering techniques. The computational results are encouraging and demonstrate that GWAC provides better values in terms of precision, recall, G-measure, and intracluster distances. GWAC is further applied for gene expression data set and its performance is compared to other techniques. Experimental results reveal the efficiency of the GWAC over other techniques.
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Affiliation(s)
- Vijay Kumar
- 1Computer Science and Engineering Department, Thapar University, Patiala, Punjab, India
| | - Jitender Kumar Chhabra
- 2Computer Engineering Department, National Institute of Technology, Kurukshetra, Haryana, India
| | - Dinesh Kumar
- 3Computer Science and Engineering Department, GJUS and T, Hisar, Haryana, India
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123
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Wen FP, Guo YS, Hu Y, Liu WX, Wang Q, Wang YT, Yu HY, Tang CM, Yang J, Zhou T, Xie ZP, Sha JH, Guo X, Li W. Distinct temporal requirements for autophagy and the proteasome in yeast meiosis. Autophagy 2016; 12:671-88. [PMID: 27050457 DOI: 10.1080/15548627.2016.1149659] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Meiosis is a special type of cellular renovation that involves 2 successive cell divisions and a single round of DNA replication. Two major degradation systems, the autophagy-lysosome and the ubiquitin-proteasome, are involved in meiosis, but their roles have yet to be elucidated. Here we show that autophagy mainly affects the initiation of meiosis but not the nuclear division. Autophagy works not only by serving as a dynamic recycling system but also by eliminating some negative meiotic regulators such as Ego4 (Ynr034w-a). In a quantitative proteomics study, the proteasome was found to be significantly upregulated during meiotic divisions. We found that proteasomal activity is essential to the 2 successive meiotic nuclear divisions but not for the initiation of meiosis. Our study defines the roles of autophagy and the proteasome in meiosis: Autophagy mainly affects the initiation of meiosis, whereas the proteasome mainly affects the 2 successive meiotic divisions.
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Affiliation(s)
- Fu-ping Wen
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,c University of Chinese Academy of Sciences , Beijing , China
| | - Yue-shuai Guo
- b State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development , Department of Histology and Embryology , Nanjing Medical University , Nanjing , Jiangsu , China
| | - Yang Hu
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,d College of Life Sciences, China West Normal University , Nanchong , China
| | - Wei-xiao Liu
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China
| | - Qian Wang
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,c University of Chinese Academy of Sciences , Beijing , China
| | - Yuan-ting Wang
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,c University of Chinese Academy of Sciences , Beijing , China
| | - Hai-Yan Yu
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,c University of Chinese Academy of Sciences , Beijing , China
| | - Chao-ming Tang
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China.,c University of Chinese Academy of Sciences , Beijing , China
| | - Jun Yang
- d College of Life Sciences, China West Normal University , Nanchong , China
| | - Tao Zhou
- b State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development , Department of Histology and Embryology , Nanjing Medical University , Nanjing , Jiangsu , China
| | - Zhi-ping Xie
- e School of Life Sciences and Biotechnology, Shanghai Jiao Tong University , Shanghai , China
| | - Jia-hao Sha
- b State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development , Department of Histology and Embryology , Nanjing Medical University , Nanjing , Jiangsu , China
| | - Xuejiang Guo
- b State Key Laboratory of Reproductive Medicine, Collaborative Innovation Center of Genetics and Development , Department of Histology and Embryology , Nanjing Medical University , Nanjing , Jiangsu , China
| | - Wei Li
- a State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences , Beijing , China
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124
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Cavero S, Herruzo E, Ontoso D, San-Segundo PA. Impact of histone H4K16 acetylation on the meiotic recombination checkpoint in Saccharomyces cerevisiae. MICROBIAL CELL 2016; 3:606-620. [PMID: 28357333 PMCID: PMC5348980 DOI: 10.15698/mic2016.12.548] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In meiotic cells, the pachytene checkpoint or meiotic recombination checkpoint is
a surveillance mechanism that monitors critical processes, such as recombination
and chromosome synapsis, which are essential for proper distribution of
chromosomes to the meiotic progeny. Failures in these processes lead to the
formation of aneuploid gametes. Meiotic recombination occurs in the context of
chromatin; in fact, the histone methyltransferase Dot1 and the histone
deacetylase Sir2 are known regulators of the pachytene checkpoint in
Saccharomyces cerevisiae. We report here that Sas2-mediated
acetylation of histone H4 at lysine 16 (H4K16ac), one of the Sir2 targets,
modulates meiotic checkpoint activity in response to synaptonemal complex
defects. We show that, like sir2, the H4-K16Q
mutation, mimicking constitutive acetylation of H4K16, eliminates the delay in
meiotic cell cycle progression imposed by the checkpoint in the
synapsis-defective zip1 mutant. We also demonstrate that, like
in dot1, zip1-induced phosphorylation of the
Hop1 checkpoint adaptor at threonine 318 and the ensuing Mek1 activation are
impaired in H4-K16 mutants. However, in contrast to
sir2 and dot1, the
H4-K16R and H4-K16Q mutations have only a
minor effect in checkpoint activation and localization of the nucleolar Pch2
checkpoint factor in ndt80-prophase-arrested cells. We also
provide evidence for a cross-talk between Dot1-dependent H3K79 methylation and
H4K16ac and show that Sir2 excludes H4K16ac from the rDNA region on meiotic
chromosomes. Our results reveal that proper levels of H4K16ac orchestrate this
meiotic quality control mechanism and that Sir2 impinges on additional targets
to fully activate the checkpoint.
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Affiliation(s)
- Santiago Cavero
- Instituto de Biología Funcional y Genómica. Consejo Superior de Investigaciones Científicas and University of Salamanca, 37007 Salamanca, Spain. ; Present address: Department of Experimental and Health Sciences, Pompeu Fabra University, 08003-Barcelona, Spain
| | - Esther Herruzo
- Instituto de Biología Funcional y Genómica. Consejo Superior de Investigaciones Científicas and University of Salamanca, 37007 Salamanca, Spain
| | - David Ontoso
- Instituto de Biología Funcional y Genómica. Consejo Superior de Investigaciones Científicas and University of Salamanca, 37007 Salamanca, Spain. ; Present address: Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Pedro A San-Segundo
- Instituto de Biología Funcional y Genómica. Consejo Superior de Investigaciones Científicas and University of Salamanca, 37007 Salamanca, Spain
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125
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Chia M, van Werven FJ. Temporal Expression of a Master Regulator Drives Synchronous Sporulation in Budding Yeast. G3 (BETHESDA, MD.) 2016; 6:3553-3560. [PMID: 27605516 PMCID: PMC5100854 DOI: 10.1534/g3.116.034983] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/29/2016] [Indexed: 11/30/2022]
Abstract
Yeast cells enter and undergo gametogenesis relatively asynchronously, making it technically challenging to perform stage-specific genomic and biochemical analyses. Cell-to-cell variation in the expression of the master regulator of entry into sporulation, IME1, has been implicated to be the underlying cause of asynchronous sporulation. Here, we find that timing of IME1 expression is of critical importance for inducing cells to undergo sporulation synchronously. When we force expression of IME1 from an inducible promoter in cells incubated in sporulation medium for 2 hr, the vast majority of cells exhibit synchrony during premeiotic DNA replication and meiotic divisions. Inducing IME1 expression too early or too late affects the synchrony of sporulation. Surprisingly, our approach for synchronous sporulation does not require growth in acetate-containing medium, but can be achieved in cells grown in rich medium until saturation. Our system requires solely IME1, because the expression of the N6-methyladenosine methyltransferase IME4, another key regulator of early sporulation, is controlled by IME1 itself. The approach described here can be combined easily with other stage-specific synchronization methods, and thereby applied to study specific stages of sporulation, or the complete sporulation program.
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Affiliation(s)
- Minghao Chia
- Cell Fate and Gene Regulation Laboratory, The Francis Crick Institute, London WC2A 3LY, UK
| | - Folkert J van Werven
- Cell Fate and Gene Regulation Laboratory, The Francis Crick Institute, London WC2A 3LY, UK
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126
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Wang D, He F, Maslov S, Gerstein M. DREISS: Using State-Space Models to Infer the Dynamics of Gene Expression Driven by External and Internal Regulatory Networks. PLoS Comput Biol 2016; 12:e1005146. [PMID: 27760135 PMCID: PMC5070849 DOI: 10.1371/journal.pcbi.1005146] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 09/15/2016] [Indexed: 11/26/2022] Open
Abstract
Gene expression is controlled by the combinatorial effects of regulatory factors from different biological subsystems such as general transcription factors (TFs), cellular growth factors and microRNAs. A subsystem’s gene expression may be controlled by its internal regulatory factors, exclusively, or by external subsystems, or by both. It is thus useful to distinguish the degree to which a subsystem is regulated internally or externally–e.g., how non-conserved, species-specific TFs affect the expression of conserved, cross-species genes during evolution. We developed a computational method (DREISS, dreiss.gerteinlab.org) for analyzing the Dynamics of gene expression driven by Regulatory networks, both External and Internal based on State Space models. Given a subsystem, the “state” and “control” in the model refer to its own (internal) and another subsystem’s (external) gene expression levels. The state at a given time is determined by the state and control at a previous time. Because typical time-series data do not have enough samples to fully estimate the model’s parameters, DREISS uses dimensionality reduction, and identifies canonical temporal expression trajectories (e.g., degradation, growth and oscillation) representing the regulatory effects emanating from various subsystems. To demonstrate capabilities of DREISS, we study the regulatory effects of evolutionarily conserved vs. divergent TFs across distant species. In particular, we applied DREISS to the time-series gene expression datasets of C. elegans and D. melanogaster during their embryonic development. We analyzed the expression dynamics of the conserved, orthologous genes (orthologs), seeing the degree to which these can be accounted for by orthologous (internal) versus species-specific (external) TFs. We found that between two species, the orthologs have matched, internally driven expression patterns but very different externally driven ones. This is particularly true for genes with evolutionarily ancient functions (e.g. the ribosomal proteins), in contrast to those with more recently evolved functions (e.g., cell-cell communication). This suggests that despite striking morphological differences, some fundamental embryonic-developmental processes are still controlled by ancient regulatory systems. The dynamics of a biological system can be controlled by its own internal mechanisms and external perturbations. To gain intuition on this, we may draw a comparison with a mass hanging from a spring. The mass will move naturally by itself but its dynamics is also affected by one’s pulling it. That is, the dynamics of the mass is governed by the effect of the external perturbations superimposed on the internal mechanism of the spring (i.e. Hooke’s law). Similarly, given a group of genes, their temporal gene expression dynamics can be controlled by both transcription factors inside the group and external regulatory factors. Therefore, it is useful to identify the expression dynamics that are exclusively controlled by internal or external factors and compare them across various systems. While state-space models have been widely used to decouple the internal and external effects in physical systems, such as the mass and spring, typical biological systems do not have enough time samples to infer all the model’s parameters, and applications of state-space models were not very effective in these instances. Hence, we developed a general-purpose computational method by integrating state-space models and dimensionality reduction to identify temporal gene expression patterns driven by internal and external regulatory networks. We applied our method to the embryonic developmental datasets in the worm and fly (and also in a human cancer context). We successfully identified the temporal expression dynamics of cross-species conserved genes that were driven by conserved and species-specific regulatory networks.
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Affiliation(s)
- Daifeng Wang
- Department of Biomedical Informatics, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook Medicine, Stony Brook, New York, United States of America
| | - Fei He
- Biology Department, Brookhaven National Laboratory, Upton, New York, United States of America
| | - Sergei Maslov
- Biology Department, Brookhaven National Laboratory, Upton, New York, United States of America
- Department of Bioengineering and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Mark Gerstein
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Computer Science, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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127
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Choose Your Own Adventure: The Role of Histone Modifications in Yeast Cell Fate. J Mol Biol 2016; 429:1946-1957. [PMID: 27769718 DOI: 10.1016/j.jmb.2016.10.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/07/2016] [Accepted: 10/07/2016] [Indexed: 12/16/2022]
Abstract
When yeast cells are challenged by a fluctuating environment, signaling networks activate differentiation programs that promote their individual or collective survival. These programs include the initiation of meiotic sporulation, the formation of filamentous growth structures, and the activation of programmed cell death pathways. The establishment and maintenance of these distinct cell fates are driven by massive gene expression programs that promote the necessary changes in morphology and physiology. While these genomic reprogramming events depend on a specialized network of transcription factors, a diverse set of chromatin regulators, including histone-modifying enzymes, chromatin remodelers, and histone variants, also play essential roles. Here, we review the broad functions of histone modifications in initiating cell fate transitions, with particular focus on their contribution to the control of expression of key genes required for the differentiation programs and chromatin reorganization that accompanies these cell fates.
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128
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Liu YT, Chang KM, Ma CH, Jayaram M. Replication-dependent and independent mechanisms for the chromosome-coupled persistence of a selfish genome. Nucleic Acids Res 2016; 44:8302-23. [PMID: 27492289 PMCID: PMC5041486 DOI: 10.1093/nar/gkw694] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/26/2016] [Accepted: 07/27/2016] [Indexed: 12/21/2022] Open
Abstract
The yeast 2-micron plasmid epitomizes the evolutionary optimization of selfish extra-chromosomal genomes for stable persistence without jeopardizing their hosts' fitness. Analyses of fluorescence-tagged single-copy reporter plasmids and/or the plasmid partitioning proteins in native and non-native hosts reveal chromosome-hitchhiking as the likely means for plasmid segregation. The contribution of the partitioning system to equal segregation is bipartite- replication-independent and replication-dependent. The former nearly eliminates 'mother bias' (preferential plasmid retention in the mother cell) according to binomial distribution, thus limiting equal segregation of a plasmid pair to 50%. The latter enhances equal segregation of plasmid sisters beyond this level, elevating the plasmid close to chromosome status. Host factors involved in plasmid partitioning can be functionally separated by their participation in the replication-independent and/or replication-dependent steps. In the hitchhiking model, random tethering of a pair of plasmids to chromosomes signifies the replication-independent component of segregation; the symmetric tethering of plasmid sisters to sister chromatids embodies the replication-dependent component. The 2-micron circle broadly resembles the episomes of certain mammalian viruses in its chromosome-associated propagation. This unifying feature among otherwise widely differing selfish genomes suggests their evolutionary convergence to the common logic of exploiting, albeit via distinct molecular mechanisms, host chromosome segregation machineries for self-preservation.
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Affiliation(s)
- Yen-Ting Liu
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Keng-Ming Chang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Chien-Hui Ma
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Makkuni Jayaram
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
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129
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Cerri R, Barros RC, P. L. F. de Carvalho AC, Jin Y. Reduction strategies for hierarchical multi-label classification in protein function prediction. BMC Bioinformatics 2016; 17:373. [PMID: 27627880 PMCID: PMC5024469 DOI: 10.1186/s12859-016-1232-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 08/30/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Hierarchical Multi-Label Classification is a classification task where the classes to be predicted are hierarchically organized. Each instance can be assigned to classes belonging to more than one path in the hierarchy. This scenario is typically found in protein function prediction, considering that each protein may perform many functions, which can be further specialized into sub-functions. We present a new hierarchical multi-label classification method based on multiple neural networks for the task of protein function prediction. A set of neural networks are incrementally training, each being responsible for the prediction of the classes belonging to a given level. RESULTS The method proposed here is an extension of our previous work. Here we use the neural network output of a level to complement the feature vectors used as input to train the neural network in the next level. We experimentally compare this novel method with several other reduction strategies, showing that it obtains the best predictive performance. Empirical results also show that the proposed method achieves better or comparable predictive performance when compared with state-of-the-art methods for hierarchical multi-label classification in the context of protein function prediction. CONCLUSIONS The experiments showed that using the output in one level as input to the next level contributed to better classification results. We believe the method was able to learn the relationships between the protein functions during training, and this information was useful for classification. We also identified in which functional classes our method performed better.
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Affiliation(s)
- Ricardo Cerri
- Department of Computer Science, UFSCar Federal University of São Carlos, Rodovia Washington Luís, Km 235, São Carlos, 13565-905 SP Brazil
| | - Rodrigo C. Barros
- Faculdade de Informática, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga, 6681, Porto Alegre, 90619-900 RS Brazil
| | - André C. P. L. F. de Carvalho
- Instituto de Ciências Matemáticas e de Computação, Universidade de São Paulo, Campus de São Carlos 135, São Carlos, 13566-590 SP Brazil
| | - Yaochu Jin
- Department of Computer Science, University of Surrey, GU2 7XH Guildford, Surrey, United Kingdom
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130
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Taghia J, Leijon A. Variational Inference for Watson Mixture Model. IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2016; 38:1886-1900. [PMID: 26571512 DOI: 10.1109/tpami.2015.2498935] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper addresses modelling data using the Watson distribution. The Watson distribution is one of the simplest distributions for analyzing axially symmetric data. This distribution has gained some attention in recent years due to its modeling capability. However, its Bayesian inference is fairly understudied due to difficulty in handling the normalization factor. Recent development of Markov chain Monte Carlo (MCMC) sampling methods can be applied for this purpose. However, these methods can be prohibitively slow for practical applications. A deterministic alternative is provided by variational methods that convert inference problems into optimization problems. In this paper, we present a variational inference for Watson mixture models. First, the variational framework is used to side-step the intractability arising from the coupling of latent states and parameters. Second, the variational free energy is further lower bounded in order to avoid intractable moment computation. The proposed approach provides a lower bound on the log marginal likelihood and retains distributional information over all parameters. Moreover, we show that it can regulate its own complexity by pruning unnecessary mixture components while avoiding over-fitting. We discuss potential applications of the modeling with Watson distributions in the problem of blind source separation, and clustering gene expression data sets.
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131
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Doyle CE, Kitty Cheung H, Spence KL, Saville BJ. Unh1, an Ustilago maydis Ndt80-like protein, controls completion of tumor maturation, teliospore development, and meiosis. Fungal Genet Biol 2016; 94:54-68. [DOI: 10.1016/j.fgb.2016.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/04/2016] [Accepted: 07/06/2016] [Indexed: 10/21/2022]
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132
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Honigberg SM. Similar environments but diverse fates: Responses of budding yeast to nutrient deprivation. MICROBIAL CELL 2016; 3:302-328. [PMID: 27917388 PMCID: PMC5134742 DOI: 10.15698/mic2016.08.516] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diploid budding yeast (Saccharomyces cerevisiae) can adopt one
of several alternative differentiation fates in response to nutrient limitation,
and each of these fates provides distinct biological functions. When different
strain backgrounds are taken into account, these various fates occur in response
to similar environmental cues, are regulated by the same signal transduction
pathways, and share many of the same master regulators. I propose that the
relationships between fate choice, environmental cues and signaling pathways are
not Boolean, but involve graded levels of signals, pathway activation and
master-regulator activity. In the absence of large differences between
environmental cues, small differences in the concentration of cues may be
reinforced by cell-to-cell signals. These signals are particularly essential for
fate determination within communities, such as colonies and biofilms, where fate
choice varies dramatically from one region of the community to another. The lack
of Boolean relationships between cues, signaling pathways, master regulators and
cell fates may allow yeast communities to respond appropriately to the wide
range of environments they encounter in nature.
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Affiliation(s)
- Saul M Honigberg
- Division of Cell Biology and Biophysics, University of Missouri-Kansas City, 5007 Rockhill Rd, Kansas City MO 64110, USA
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133
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Yan GX, Zhang J, Shodhan A, Tian M, Miao W. Cdk3, a conjugation-specific cyclin-dependent kinase, is essential for the initiation of meiosis in Tetrahymena thermophila. Cell Cycle 2016; 15:2506-14. [PMID: 27420775 DOI: 10.1080/15384101.2016.1207838] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Meiosis is an important process in sexual reproduction. Meiosis initiation has been found to be highly diverse among species. In yeast, it has been established that cyclin-dependent kinases (Cdks) and cyclins are essential components in the meiosis initiation pathway. In this study, we identified 4 Cdks in the model ciliate, Tetrahymena thermophila, and we found one of them, Cdk3, which is specifically expressed during early conjugation, to be essential for meiosis initiation. Cdk3 deletion led to arrest at the pair formation stage of conjugation. We then confirmed that Cdk3 acts upstream of double-strand break (DSB) formation. Moreover, we detected that Cdk3 is necessary for the expression of many genes involved in early meiotic events. Through proteomic quantification of phosphorylation, co-expression analysis and RNA-Seq analyses, we identified a conjugation-specific cyclin, Cyc2, which most likely partners with Cdk3 to initiate meiosis.
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Affiliation(s)
- Guan-Xiong Yan
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Jing Zhang
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Anura Shodhan
- c Department of Chromosome Biology and Max F. Perutz Laboratories , Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Miao Tian
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,c Department of Chromosome Biology and Max F. Perutz Laboratories , Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Wei Miao
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China
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134
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Quigley DA, Kandyba E, Huang P, Halliwill KD, Sjölund J, Pelorosso F, Wong CE, Hirst GL, Wu D, Delrosario R, Kumar A, Balmain A. Gene Expression Architecture of Mouse Dorsal and Tail Skin Reveals Functional Differences in Inflammation and Cancer. Cell Rep 2016; 16:1153-1165. [PMID: 27425619 DOI: 10.1016/j.celrep.2016.06.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/16/2016] [Accepted: 06/14/2016] [Indexed: 12/13/2022] Open
Abstract
Inherited germline polymorphisms can cause gene expression levels in normal tissues to differ substantially between individuals. We present an analysis of the genetic architecture of normal adult skin from 470 genetically unique mice, demonstrating the effect of germline variants, skin tissue location, and perturbation by exogenous inflammation or tumorigenesis on gene signaling pathways. Gene networks related to specific cell types and signaling pathways, including sonic hedgehog (Shh), Wnt, Lgr family stem cell markers, and keratins, differed at these tissue sites, suggesting mechanisms for the differential susceptibility of dorsal and tail skin to development of skin diseases and tumorigenesis. The Pten tumor suppressor gene network is rewired in premalignant tumors compared to normal tissue, but this response to perturbation is lost during malignant progression. We present a software package for expression quantitative trait loci (eQTL) network analysis and demonstrate how network analysis of whole tissues provides insights into interactions between cell compartments and signaling molecules.
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Affiliation(s)
- David A Quigley
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Genetics, Institute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital, Oslo 0310, Norway; K.G. Jebsen Centre for Breast Cancer Research, Institute for Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo 0313, Norway; Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Eve Kandyba
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Phillips Huang
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Genome Institute of Singapore, 60 Biopolis Street, #02-01 Genome Building, Singapore 138672, Singapore
| | - Kyle D Halliwill
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jonas Sjölund
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, 22381 Lund, Sweden
| | - Facundo Pelorosso
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 9(th) Floor, Ciudad Autónoma de Buenos Aires 1121, Argentina
| | - Christine E Wong
- Institute of Surgical Pathology, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Gillian L Hirst
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Di Wu
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Reyno Delrosario
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Atul Kumar
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Allan Balmain
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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135
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Garcia G, Finnigan GC, Heasley LR, Sterling SM, Aggarwal A, Pearson CG, Nogales E, McMurray MA, Thorner J. Assembly, molecular organization, and membrane-binding properties of development-specific septins. J Cell Biol 2016; 212:515-29. [PMID: 26929450 PMCID: PMC4772501 DOI: 10.1083/jcb.201511029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Analysis of the contribution of meiotic septins Spr3 and Spr28 to overall septin complex architecture at the ultrastructural level provides insights into how alternative subunits endow septin complexes with unique properties. Septin complexes display remarkable plasticity in subunit composition, yet how a new subunit assembled into higher-order structures confers different functions is not fully understood. Here, this question is addressed in budding yeast, where during meiosis Spr3 and Spr28 replace the mitotic septin subunits Cdc12 and Cdc11 (and Shs1), respectively. In vitro, the sole stable complex that contains both meiosis-specific septins is a linear Spr28–Spr3–Cdc3–Cdc10–Cdc10–Cdc3–Spr3–Spr28 hetero-octamer. Only coexpressed Spr3 and Spr28 colocalize with Cdc3 and Cdc10 in mitotic cells, indicating that incorporation requires a Spr28-Spr3 protomer. Unlike their mitotic counterparts, Spr28-Spr3–capped rods are unable to form higher-order structures in solution but assemble to form long paired filaments on lipid monolayers containing phosphatidylinositol-4,5-bisphosphate, mimicking presence of this phosphoinositide in the prospore membrane. Spr28 and Spr3 fail to rescue the lethality of a cdc11Δ cdc12Δ mutant, and Cdc11 and Cdc12 fail to restore sporulation proficiency to spr3Δ/spr3Δ spr28Δ/spr28Δ diploids. Thus, specific meiotic and mitotic subunits endow septin complexes with functionally distinct properties.
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Affiliation(s)
- Galo Garcia
- Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Gregory C Finnigan
- Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Lydia R Heasley
- Department of Cell and Developmental Biology, University of Colorado Denver School of Medicine, Aurora, CO 80045
| | - Sarah M Sterling
- Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Adeeti Aggarwal
- Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado Denver School of Medicine, Aurora, CO 80045
| | - Eva Nogales
- Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720 Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Michael A McMurray
- Department of Cell and Developmental Biology, University of Colorado Denver School of Medicine, Aurora, CO 80045
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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136
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Liang Y, Kelemen A, Tayo B. Model-based or algorithm-based? Statistical evidence for diabetes and treatments using gene expression. Stat Methods Med Res 2016; 16:139-53. [PMID: 17484297 DOI: 10.1177/0962280206071927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gene expression profiles obtained from samples of diabetic and normal rats with and without treatments can be used to identify genes that distinguish normal and diabetic individuals and also to evaluate the effectiveness of drug treatments. This study examines changes in global gene expression in rat muscle caused by streptozotocin-induced diabetes and vanadyl sulfate treatment. We explored model-based and algorithm-based methods with gene screening measures for microarray gene expression data to classify and predict individuals with high risk of diabetes. Results show that the mixed ANOVA model-based approach provides an efficient way to conduct an investigation of the inherent variability in gene expression data and to estimate the effects of experimental factors such as treatments and diseases and their interactions. The algorithm-based weighted voting and neural network classifiers show good classification performance for the diabetes and treatment groups. Although neural network performs better than weighted voting with higher classification rate, the interpretation of weighted voting is more straightforward. The study indicates that the choice of the gene selection procedure is at least as important as the choice of the classification procedure. We conclude that both mixed model-based and algorithm-based approaches provide the statistical evidence of the biological hypotheses that vanadyl sulfate treatment of diabetic animals restores gene expression patterns to normal. Although model-based and algorithm-based methods provide different strengths and perspective for the analysis of the same set of data, in general both can be considered and developed for analyzing factorial design experiments with multiple groups and factors. This study represents a major step towards the discovery of responsible genes related to diabetes and its treatment.
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Affiliation(s)
- Yulan Liang
- Department of Biostatistics, The State University of New York, Buffalo 14214, USA.
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137
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Xie B, Horecka J, Chu A, Davis RW, Becker E, Primig M. Ndt80 activates the meiotic ORC1 transcript isoform and SMA2 via a bi-directional middle sporulation element in Saccharomyces cerevisiae. RNA Biol 2016; 13:772-82. [PMID: 27362276 DOI: 10.1080/15476286.2016.1191738] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The origin of replication complex subunit ORC1 is important for DNA replication. The gene is known to encode a meiotic transcript isoform (mORC1) with an extended 5'-untranslated region (5'-UTR), which was predicted to inhibit protein translation. However, the regulatory mechanism that controls the mORC1 transcript isoform is unknown and no molecular biological evidence for a role of mORC1 in negatively regulating Orc1 protein during gametogenesis is available. By interpreting RNA profiling data obtained with growing and sporulating diploid cells, mitotic haploid cells, and a starving diploid control strain, we determined that mORC1 is a middle meiotic transcript isoform. Regulatory motif predictions and genetic experiments reveal that the activator Ndt80 and its middle sporulation element (MSE) target motif are required for the full induction of mORC1 and the divergently transcribed meiotic SMA2 locus. Furthermore, we find that the MSE-binding negative regulator Sum1 represses both mORC1 and SMA2 during mitotic growth. Finally, we demonstrate that an MSE deletion strain, which cannot induce mORC1, contains abnormally high Orc1 levels during post-meiotic stages of gametogenesis. Our results reveal the regulatory mechanism that controls mORC1, highlighting a novel developmental stage-specific role for the MSE element in bi-directional mORC1/SMA2 gene activation, and correlating mORC1 induction with declining Orc1 protein levels. Because eukaryotic genes frequently encode multiple transcripts possessing 5'-UTRs of variable length, our results are likely relevant for gene expression during development and disease in higher eukaryotes.
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Affiliation(s)
- Bingning Xie
- a Inserm U1085 IRSET, Université de Rennes 1 , Rennes , France
| | - Joe Horecka
- b Stanford Genome Technology Center , Palo Alto , CA , USA
| | - Angela Chu
- b Stanford Genome Technology Center , Palo Alto , CA , USA
| | - Ronald W Davis
- b Stanford Genome Technology Center , Palo Alto , CA , USA.,c Departments of Biochemistry and Genetics , Stanford University , Stanford , CA , USA
| | | | - Michael Primig
- a Inserm U1085 IRSET, Université de Rennes 1 , Rennes , France
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138
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Abstract
A convergence between molecular biological technique and the technology of miniaturization has produced the "gene chip" or microhybridization array. This device multiplies by several thousand fold the power of the northern blot for studying gene expression. Now, it is possible to survey simultaneously a large fraction of all genes in an experimental organism, and within a few years all of the approximately 140,000 human genes will be within reach of the technique. This capability is not only accelerating the rate of research into gene expression and function, it is changing the perspective of inquiry from single genes in isolation to networks of genes operating as a system. Many neurological diseases, from hydrocephalus to schizophrenia, have a genetic component, and individual responses to therapeutic drugs can vary with the genetic background of patients. In neurology and neurobiology, the ability to obtain "gene expression profiles" from nervous tissue promises to illuminate interactions between neuronal genes and the environment, development, disease, aging, and response to drugs and injury.
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Affiliation(s)
- R Douglas Fields
- Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Nesrin Ozsarac
- Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
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139
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Rikhtehgaran R, Kazemi I. The determination of uncertainty levels in robust clustering of subjects with longitudinal observations using the Dirichlet process mixture. ADV DATA ANAL CLASSI 2016. [DOI: 10.1007/s11634-016-0262-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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140
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Cuf2 Is a Transcriptional Co-Regulator that Interacts with Mei4 for Timely Expression of Middle-Phase Meiotic Genes. PLoS One 2016; 11:e0151914. [PMID: 26986212 PMCID: PMC4795683 DOI: 10.1371/journal.pone.0151914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/07/2016] [Indexed: 11/19/2022] Open
Abstract
The Schizosaccharomyces pombe cuf2+ gene encodes a nuclear regulator that is required for timely activation and repression of several middle-phase genes during meiotic differentiation. In this study, we sought to gain insight into the mechanism by which Cuf2 regulates meiotic gene expression. Using a chromatin immunoprecipitation approach, we demonstrate that Cuf2 is specifically associated with promoters of both activated and repressed target genes, in a time-dependent manner. In case of the fzr1+ gene whose transcription is positively affected by Cuf2, promoter occupancy by Cuf2 results in a concomitant increased association of RNA polymerase II along its coding region. In marked contrast, association of RNA polymerase II with chromatin decreases when Cuf2 negatively regulates target gene expression such as wtf13+. Although Cuf2 operates through a transcriptional mechanism, it is unable to perform its function in the absence of the Mei4 transcription factor, which is a member of the conserved forkhead protein family. Using coimmunoprecipitation experiments, results showed that Cuf2 is a binding partner of Mei4. Bimolecular fluorescence complementation experiments brought further evidence that an association between Cuf2 and Mei4 occurs in the nucleus. Analysis of fzr1+ promoter regions revealed that two FLEX-like elements, which are bound by the transcription factor Mei4, are required for chromatin occupancy by Cuf2. Together, results reported here revealed that Cuf2 and Mei4 co-regulate the timely expression of middle-phase genes during meiosis.
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141
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Schmoll M, Dattenböck C, Carreras-Villaseñor N, Mendoza-Mendoza A, Tisch D, Alemán MI, Baker SE, Brown C, Cervantes-Badillo MG, Cetz-Chel J, Cristobal-Mondragon GR, Delaye L, Esquivel-Naranjo EU, Frischmann A, Gallardo-Negrete JDJ, García-Esquivel M, Gomez-Rodriguez EY, Greenwood DR, Hernández-Oñate M, Kruszewska JS, Lawry R, Mora-Montes HM, Muñoz-Centeno T, Nieto-Jacobo MF, Nogueira Lopez G, Olmedo-Monfil V, Osorio-Concepcion M, Piłsyk S, Pomraning KR, Rodriguez-Iglesias A, Rosales-Saavedra MT, Sánchez-Arreguín JA, Seidl-Seiboth V, Stewart A, Uresti-Rivera EE, Wang CL, Wang TF, Zeilinger S, Casas-Flores S, Herrera-Estrella A. The Genomes of Three Uneven Siblings: Footprints of the Lifestyles of Three Trichoderma Species. Microbiol Mol Biol Rev 2016; 80:205-327. [PMID: 26864432 PMCID: PMC4771370 DOI: 10.1128/mmbr.00040-15] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genus Trichoderma contains fungi with high relevance for humans, with applications in enzyme production for plant cell wall degradation and use in biocontrol. Here, we provide a broad, comprehensive overview of the genomic content of these species for "hot topic" research aspects, including CAZymes, transport, transcription factors, and development, along with a detailed analysis and annotation of less-studied topics, such as signal transduction, genome integrity, chromatin, photobiology, or lipid, sulfur, and nitrogen metabolism in T. reesei, T. atroviride, and T. virens, and we open up new perspectives to those topics discussed previously. In total, we covered more than 2,000 of the predicted 9,000 to 11,000 genes of each Trichoderma species discussed, which is >20% of the respective gene content. Additionally, we considered available transcriptome data for the annotated genes. Highlights of our analyses include overall carbohydrate cleavage preferences due to the different genomic contents and regulation of the respective genes. We found light regulation of many sulfur metabolic genes. Additionally, a new Golgi 1,2-mannosidase likely involved in N-linked glycosylation was detected, as were indications for the ability of Trichoderma spp. to generate hybrid galactose-containing N-linked glycans. The genomic inventory of effector proteins revealed numerous compounds unique to Trichoderma, and these warrant further investigation. We found interesting expansions in the Trichoderma genus in several signaling pathways, such as G-protein-coupled receptors, RAS GTPases, and casein kinases. A particularly interesting feature absolutely unique to T. atroviride is the duplication of the alternative sulfur amino acid synthesis pathway.
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Affiliation(s)
- Monika Schmoll
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | - Christoph Dattenböck
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | | | | | - Doris Tisch
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - Mario Ivan Alemán
- Cinvestav, Department of Genetic Engineering, Irapuato, Guanajuato, Mexico
| | - Scott E Baker
- Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Christopher Brown
- University of Otago, Department of Biochemistry and Genetics, Dunedin, New Zealand
| | | | - José Cetz-Chel
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | | | - Luis Delaye
- Cinvestav, Department of Genetic Engineering, Irapuato, Guanajuato, Mexico
| | | | - Alexa Frischmann
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | | | - Monica García-Esquivel
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | | | - David R Greenwood
- The University of Auckland, School of Biological Sciences, Auckland, New Zealand
| | - Miguel Hernández-Oñate
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | - Joanna S Kruszewska
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Laboratory of Fungal Glycobiology, Warsaw, Poland
| | - Robert Lawry
- Lincoln University, Bio-Protection Research Centre, Lincoln, Canterbury, New Zealand
| | | | | | | | | | | | | | - Sebastian Piłsyk
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Laboratory of Fungal Glycobiology, Warsaw, Poland
| | - Kyle R Pomraning
- Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Aroa Rodriguez-Iglesias
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | | | | | - Verena Seidl-Seiboth
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | | | | | - Chih-Li Wang
- National Chung-Hsing University, Department of Plant Pathology, Taichung, Taiwan
| | - Ting-Fang Wang
- Academia Sinica, Institute of Molecular Biology, Taipei, Taiwan
| | - Susanne Zeilinger
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria University of Innsbruck, Institute of Microbiology, Innsbruck, Austria
| | | | - Alfredo Herrera-Estrella
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
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142
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Ghosh AK, Wangsanut T, Fonzi WA, Rolfes RJ. The GRF10 homeobox gene regulates filamentous growth in the human fungal pathogen Candida albicans. FEMS Yeast Res 2015; 15:fov093. [PMID: 26472755 PMCID: PMC4705307 DOI: 10.1093/femsyr/fov093] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/14/2015] [Accepted: 10/07/2015] [Indexed: 12/14/2022] Open
Abstract
Candida albicans is the most common human fungal pathogen and can cause life-threatening infections. Filamentous growth is critical in the pathogenicity of C. albicans, as the transition from yeast to hyphal forms is linked to virulence and is also a pivotal process in fungal biofilm development. Homeodomain-containing transcription factors have been linked to developmental processes in fungi and other eukaryotes. We report here on GRF10, a homeobox transcription factor-encoding gene that plays a role in C. albicans filamentation. Deletion of the GRF10 gene, in both C. albicans SN152 and BWP17 strain backgrounds, results in mutants with strongly decreased hyphal growth. The mutants are defective in chlamydospore and biofilm formation, as well as showing dramatically attenuated virulence in a mouse infection model. Expression of the GRF10 gene is highly induced during stationary phase and filamentation. In summary, our study emphasizes a new role for the homeodomain-containing transcription factor in morphogenesis and pathogenicity of C. albicans.
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Affiliation(s)
- Anup K Ghosh
- Department of Biology, Georgetown University, Washington, DC 20057, USA
| | | | - William A Fonzi
- Department of Microbiology and Immunology, Georgetown University, Washington, DC 20057, USA
| | - Ronda J Rolfes
- Department of Biology, Georgetown University, Washington, DC 20057, USA
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143
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Post-transcriptional regulation in budding yeast meiosis. Curr Genet 2015; 62:313-5. [PMID: 26613728 DOI: 10.1007/s00294-015-0546-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 01/12/2023]
Abstract
The precise regulation of gene expression is essential for developmental processes in eukaryotic organisms. As an important post-transcriptional regulatory point, translational control is complementary to transcriptional regulation. Sporulation in the budding yeast Saccharomyces cerevisiae is a developmental process controlled by a well-studied transcriptional cascade that drives the cell through the events of DNA replication, meiotic chromosome segregation, and spore assembly. Recent studies have revealed that as cells begin the meiotic divisions, translational regulation of gene expression fine tunes this transcriptional cascade. The significance and mechanisms of this translational regulation are beginning to emerge. These studies may also provide insights into translational regulation in germ cell development of multicellular organisms.
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144
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SPO73 and SPO71 Function Cooperatively in Prospore Membrane Elongation During Sporulation in Saccharomyces cerevisiae. PLoS One 2015; 10:e0143571. [PMID: 26605945 PMCID: PMC4659569 DOI: 10.1371/journal.pone.0143571] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/08/2015] [Indexed: 01/21/2023] Open
Abstract
In the yeast Saccharomyces cerevisiae, cells undergoing sporulation form prospore membranes to surround their meiotic nuclei. The prospore membranes ultimately become the plasma membranes of the new cells. The putative phospholipase Spo1 and the tandem Pleckstrin Homology domain protein Spo71 have previously been shown to be required for prospore membrane development, along with the constitutively expressed Vps13 involved in vacuolar sorting. Here, we utilize genetic analysis, and find that SPO73 is required for proper prospore membrane shape and, like SPO71, is necessary for prospore membrane elongation. Additionally, similar to SPO71, loss of SPO73 partially suppresses spo1Δ. Spo73 localizes to prospore membranes and complexes with Spo71. We also find that phosphatidylserine localizes to the prospore membrane. Our results suggest a model where SPO71 and SPO73 act in opposition to SPO1 to form and elongate prospore membranes, while VPS13 plays a distinct role in prospore membrane development.
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145
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Szklarczyk R, Megchelenbrink W, Cizek P, Ledent M, Velemans G, Szklarczyk D, Huynen MA. WeGET: predicting new genes for molecular systems by weighted co-expression. Nucleic Acids Res 2015; 44:D567-73. [PMID: 26582928 PMCID: PMC4702868 DOI: 10.1093/nar/gkv1228] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/30/2015] [Indexed: 01/04/2023] Open
Abstract
We have developed the Weighted Gene Expression Tool and database (WeGET, http://weget.cmbi.umcn.nl) for the prediction of new genes of a molecular system by correlated gene expression. WeGET utilizes a compendium of 465 human and 560 murine gene expression datasets that have been collected from multiple tissues under a wide range of experimental conditions. It exploits this abundance of expression data by assigning a high weight to datasets in which the known genes of a molecular system are harmoniously up- and down-regulated. WeGET ranks new candidate genes by calculating their weighted co-expression with that system. A weighted rank is calculated for human genes and their mouse orthologs. Then, an integrated gene rank and p-value is computed using a rank-order statistic. We applied our method to predict novel genes that have a high degree of co-expression with Gene Ontology terms and pathways from KEGG and Reactome. For each query set we provide a list of predicted novel genes, computed weights for transcription datasets used and cell and tissue types that contributed to the final predictions. The performance for each query set is assessed by 10-fold cross-validation. Finally, users can use the WeGET to predict novel genes that co-express with a custom query set.
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Affiliation(s)
- Radek Szklarczyk
- Maastricht University Medical Centre, P. Debyelaan 25, 6226XM Maastricht, The Netherlands Centre for Molecular and Biomolecular Informatics (CMBI), Radboud University Medical Centre, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, Nijmegen, The Netherlands
| | - Wout Megchelenbrink
- Centre for Molecular and Biomolecular Informatics (CMBI), Radboud University Medical Centre, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, Nijmegen, The Netherlands Institute for Computing and Information Sciences (ICIS), Radboud University, Toernooiveld 212, 6525 EC Nijmegen, The Netherlands Centre for Systems Biology and Bioenergetics (CSBB), Radboud University Medical Centre, Geert Grooteplein Zuid 10, 6500 HB Nijmegen, Nijmegen, The Netherlands
| | - Pavel Cizek
- Centre for Molecular and Biomolecular Informatics (CMBI), Radboud University Medical Centre, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, Nijmegen, The Netherlands
| | - Marie Ledent
- Maastricht University Medical Centre, P. Debyelaan 25, 6226XM Maastricht, The Netherlands
| | - Gonny Velemans
- Centre for Molecular and Biomolecular Informatics (CMBI), Radboud University Medical Centre, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, Nijmegen, The Netherlands
| | - Damian Szklarczyk
- Institute of Molecular Life Sciences and Swiss Institute of Bioinformatics, University of Zurich, 8057 Zurich, Switzerland
| | - Martijn A Huynen
- Centre for Molecular and Biomolecular Informatics (CMBI), Radboud University Medical Centre, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, Nijmegen, The Netherlands Centre for Systems Biology and Bioenergetics (CSBB), Radboud University Medical Centre, Geert Grooteplein Zuid 10, 6500 HB Nijmegen, Nijmegen, The Netherlands
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146
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Cell Differentiation and Spatial Organization in Yeast Colonies: Role of Cell-Wall Integrity Pathway. Genetics 2015; 201:1427-38. [PMID: 26510787 DOI: 10.1534/genetics.115.180919] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/10/2015] [Indexed: 11/18/2022] Open
Abstract
Many microbial communities contain organized patterns of cell types, yet relatively little is known about the mechanism or function of this organization. In colonies of the budding yeast Saccharomyces cerevisiae, sporulation occurs in a highly organized pattern, with a top layer of sporulating cells sharply separated from an underlying layer of nonsporulating cells. A mutant screen identified the Mpk1 and Bck1 kinases of the cell-wall integrity (CWI) pathway as specifically required for sporulation in colonies. The CWI pathway was induced as colonies matured, and a target of this pathway, the Rlm1 transcription factor, was activated specifically in the nonsporulating cell layer, here termed feeder cells. Rlm1 stimulates permeabilization of feeder cells and promotes sporulation in an overlying cell layer through a cell-nonautonomous mechanism. The relative fraction of the colony apportioned to feeder cells depends on nutrient environment, potentially buffering sexual reproduction against suboptimal environments.
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147
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Extreme Diversity in the Regulation of Ndt80-Like Transcription Factors in Fungi. G3-GENES GENOMES GENETICS 2015; 5:2783-92. [PMID: 26497142 PMCID: PMC4683649 DOI: 10.1534/g3.115.021378] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Saccharomyces cerevisiaeNdt80 protein is the founding member of a class of p53-like transcription factors that is known as the NDT80/PhoG-like DNA-binding family. The number of NDT80-like genes in different fungi is highly variable and their roles, which have been examined in only a few species, include regulation of meiosis, sexual development, biofilm formation, drug resistance, virulence, the response to nutrient stress and programmed cell death. The protein kinase Ime2 regulates the single NDT80 gene present in S. cerevisiae. In this study we used a genetic approach to investigate whether the Aspergillus nidulansIme2 homolog, ImeB, and/or protein kinases MpkC, PhoA and PhoB regulate the two NDT80-like genes (xprG and ndtA) in A. nidulans. Disruption of imeB, but not mpkC, phoA or phoB, led to increased extracellular protease activity and a defect in mycotoxin production similar to the xprG1 gain-of-function mutation. Quantitative RT-PCR showed that ImeB is a negative regulator of xprG expression and XprG is a negative regulator of xprG and ndtA expression. Thus, in contrast to Ime2, which is a positive regulator of NDT80 in S. cerevisiae, ImeB is a negative regulator as in Neurospora crassa. However, the ability of Ndt80 to autoregulate NDT80 is conserved in A. nidulans though the autoregulatory effect is negative rather than positive. Unlike N. crassa, a null mutation in imeB does not circumvent the requirement for XprG or NdtA. These results show that the regulatory activities of Ime2 and Ndt80-like proteins display an extraordinarily level of evolutionary flexibility.
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148
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Li H, Richardson WD. Evolution of the CNS myelin gene regulatory program. Brain Res 2015; 1641:111-121. [PMID: 26474911 DOI: 10.1016/j.brainres.2015.10.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/06/2023]
Abstract
Myelin is a specialized subcellular structure that evolved uniquely in vertebrates. A myelinated axon conducts action potentials many times faster than an unmyelinated axon of the same diameter; for the same conduction speed, the unmyelinated axon would need a much larger diameter and volume than its myelinated counterpart. Hence myelin speeds information transfer and saves space, allowing the evolution of a powerful yet portable brain. Myelination in the central nervous system (CNS) is controlled by a gene regulatory program that features a number of master transcriptional regulators including Olig1, Olig2 and Myrf. Olig family genes evolved from a single ancestral gene in non-chordates. Olig2, which executes multiple functions with regard to oligodendrocyte identity and development in vertebrates, might have evolved functional versatility through post-translational modification, especially phosphorylation, as illustrated by its evolutionarily conserved serine/threonine phospho-acceptor sites and its accumulation of serine residues during more recent stages of vertebrate evolution. Olig1, derived from a duplicated copy of Olig2 in early bony fish, is involved in oligodendrocyte development and is critical to remyelination in bony vertebrates, but is lost in birds. The origin of Myrf orthologs might be the result of DNA integration between an invading phage or bacterium and an early protist, producing a fusion protein capable of self-cleavage and DNA binding. Myrf seems to have adopted new functions in early vertebrates - initiation of the CNS myelination program as well as the maintenance of mature oligodendrocyte identity and myelin structure - by developing new ways to interact with DNA motifs specific to myelin genes. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Huiliang Li
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK.
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
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149
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Usher J, Thomas G, Haynes K. Utilising established SDL-screening methods as a tool for the functional genomic characterisation of model and non-model organisms. FEMS Yeast Res 2015; 15:fov091. [PMID: 26472754 DOI: 10.1093/femsyr/fov091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 12/21/2022] Open
Abstract
The trend for large-scale genetic and phenotypic screens has revealed a wealth of information on biological systems. A major challenge is understanding how genes function and putative roles in networks. The majority of current gene knowledge is garnered from studies utilising the model yeast Saccharomyces cerevisiae. We demonstrate that synthetic dosage lethal genetic array methodologies can be used to study genetic networks in other yeasts, namely the fungal pathogen Candida glabrata, which has limited forward genetic tools, due to the lack of 'natural' mating. We performed two SDL screens in S. cerevisiae, overexpressing the transcriptional regulator UME6 as bait in the first screen and its C. glabrata ortholog CAGL0F05357g in the second. Analysis revealed that SDL maps share 204 common interactors, with 10 genetic interactions unique to C. glabrata indicating a level of genetic rewiring, indicative of linking genotype to phenotype in fungal pathogens. This was further validated by incorporating our results into the global genetic landscape map of the cell from Costanzo et al. to identify common and novel gene attributes. This data demonstrated the utility large data sets and more robust analysis made possible by interrogating exogenous genes in the context of the eukaryotic global genetic landscape.
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Affiliation(s)
- Jane Usher
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Graham Thomas
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Ken Haynes
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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150
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Kalidhasan N, Joshi D, Bhatt TK, Gupta AK. Identification of key genes involved in root development of tomato using expressed sequence tag analysis. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2015; 21:491-503. [PMID: 26600676 PMCID: PMC4646861 DOI: 10.1007/s12298-015-0304-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/19/2015] [Accepted: 06/09/2015] [Indexed: 05/11/2023]
Abstract
Root system of plants are actually fascinating structures, not only critical for plant development, but also important for storage and conduction. Due to its agronomic importance, identification of genes involved in root development has been a subject of intense study. Tomato is the one of the most consumed vegetables in the world. Tomato has been used as model system for dicot plants because of its small genome, well-established transformation techniques and well-constructed physical map. The present study is targeted to identify of root specific genes expressed temporally and also gene(s) involved in lateral root and profuse root development. A total of 890 ESTs were identified from five EST libraries constructed using SSH approach which included temporal gene regulation (early and late) and genes involved in morphogenetic traits (lateral and profuse rooting). One hundred sixty-one unique ESTs identified from various libraries were categorized based on their putative functions and deposited in NCBI-dbEST database. In addition, 36 ESTs were selected for validation of their expression by RT-PCR. The present findings will help in shedding light to the unexplored developmental process of root growth in tomato and plant in general.
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Affiliation(s)
- N. Kalidhasan
- />Department of Plant Biotechnology, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021 India
| | - Deepti Joshi
- />Department of Biotechnology, School of LifeSciences, Central University of Rajasthan, Bandarsindri, 305801 India
| | - Tarun Kumar Bhatt
- />Department of Biotechnology, School of LifeSciences, Central University of Rajasthan, Bandarsindri, 305801 India
| | - Aditya Kumar Gupta
- />Department of Plant Biotechnology, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021 India
- />Department of Biotechnology, School of LifeSciences, Central University of Rajasthan, Bandarsindri, 305801 India
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