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Coffman VC, Wu P, Parthun MR, Wu JQ. CENP-A exceeds microtubule attachment sites in centromere clusters of both budding and fission yeast. ACTA ACUST UNITED AC 2012; 195:563-72. [PMID: 22084306 PMCID: PMC3257534 DOI: 10.1083/jcb.201106078] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The stoichiometries of kinetochores and their constituent proteins in yeast and vertebrate cells were determined using the histone H3 variant CENP-A, known as Cse4 in budding yeast, as a counting standard. One Cse4-containing nucleosome exists in the centromere (CEN) of each chromosome, so it has been assumed that each anaphase CEN/kinetochore cluster contains 32 Cse4 molecules. We report that anaphase CEN clusters instead contained approximately fourfold more Cse4 in Saccharomyces cerevisiae and ~40-fold more CENP-A (Cnp1) in Schizosaccharomyces pombe than predicted. These results suggest that the number of CENP-A molecules exceeds the number of kinetochore-microtubule (MT) attachment sites on each chromosome and that CENP-A is not the sole determinant of kinetochore assembly sites in either yeast. In addition, we show that fission yeast has enough Dam1-DASH complex for ring formation around attached MTs. The results of this study suggest the need for significant revision of existing CEN/kinetochore architectural models.
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Affiliation(s)
- Valerie C Coffman
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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Ilmén M, den Haan R, Brevnova E, McBride J, Wiswall E, Froehlich A, Koivula A, Voutilainen SP, Siika-aho M, la Grange DC, Thorngren N, Ahlgren S, Mellon M, Deleault K, Rajgarhia V, van Zyl WH, Penttilä M. High level secretion of cellobiohydrolases by Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2011; 4:30. [PMID: 21910902 PMCID: PMC3224389 DOI: 10.1186/1754-6834-4-30] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Accepted: 09/12/2011] [Indexed: 05/07/2023]
Abstract
BACKGROUND The main technological impediment to widespread utilization of lignocellulose for the production of fuels and chemicals is the lack of low-cost technologies to overcome its recalcitrance. Organisms that hydrolyze lignocellulose and produce a valuable product such as ethanol at a high rate and titer could significantly reduce the costs of biomass conversion technologies, and will allow separate conversion steps to be combined in a consolidated bioprocess (CBP). Development of Saccharomyces cerevisiae for CBP requires the high level secretion of cellulases, particularly cellobiohydrolases. RESULTS We expressed various cellobiohydrolases to identify enzymes that were efficiently secreted by S. cerevisiae. For enhanced cellulose hydrolysis, we engineered bimodular derivatives of a well secreted enzyme that naturally lacks the carbohydrate-binding module, and constructed strains expressing combinations of cbh1 and cbh2 genes. Though there was significant variability in the enzyme levels produced, up to approximately 0.3 g/L CBH1 and approximately 1 g/L CBH2 could be produced in high cell density fermentations. Furthermore, we could show activation of the unfolded protein response as a result of cellobiohydrolase production. Finally, we report fermentation of microcrystalline cellulose (Avicel™) to ethanol by CBH-producing S. cerevisiae strains with the addition of beta-glucosidase. CONCLUSIONS Gene or protein specific features and compatibility with the host are important for efficient cellobiohydrolase secretion in yeast. The present work demonstrated that production of both CBH1 and CBH2 could be improved to levels where the barrier to CBH sufficiency in the hydrolysis of cellulose was overcome.
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Affiliation(s)
- Marja Ilmén
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, FI-02044 VTT, Finland
| | - Riaan den Haan
- Department of Microbiology, University of Stellenbosch, De Beer Street, Stellenbosch 7600, South Africa
| | - Elena Brevnova
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - John McBride
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - Erin Wiswall
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - Allan Froehlich
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - Anu Koivula
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, FI-02044 VTT, Finland
| | - Sanni P Voutilainen
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, FI-02044 VTT, Finland
| | - Matti Siika-aho
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, FI-02044 VTT, Finland
| | - Daniël C la Grange
- Department of Microbiology, University of Stellenbosch, De Beer Street, Stellenbosch 7600, South Africa
| | - Naomi Thorngren
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - Simon Ahlgren
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - Mark Mellon
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - Kristen Deleault
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
| | - Vineet Rajgarhia
- Mascoma Corporation, 67 Etna Road, Suite 300, Lebanon, NH 03766, USA
- Total Gas & Power, 5858 Horton Street, Suite 253, Emeryville, CA 94608, USA
| | - Willem H van Zyl
- Department of Microbiology, University of Stellenbosch, De Beer Street, Stellenbosch 7600, South Africa
| | - Merja Penttilä
- VTT Technical Research Centre of Finland, Tietotie 2, Espoo, FI-02044 VTT, Finland
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Rodley CDM, Bertels F, Jones B, O'Sullivan JM. Global identification of yeast chromosome interactions using Genome conformation capture. Fungal Genet Biol 2009; 46:879-86. [PMID: 19628047 DOI: 10.1016/j.fgb.2009.07.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 07/15/2009] [Accepted: 07/16/2009] [Indexed: 12/17/2022]
Abstract
The association of chromosomes with each other and other nuclear components plays a critical role in nuclear organization and Genome function. Here, using a novel and generally applicable methodology (Genome conformation capture [GCC]), we reveal the network of chromosome interactions for the yeast Saccharomyces cerevisiae. Inter- and intra-chromosomal interactions are non-random and the number of interactions per open reading frame depends upon the dispensability of the gene product. Chromosomal interfaces are organized and provide evidence of folding within chromosomes. Interestingly, the genomic connections also involve the 2 microm plasmid and the mitochondrial genome. Mitochondrial interaction partners include genes of alpha-proteobacterial origin and the ribosomal DNA. Organization of the 2 microm plasmid aligns two inverted repeats (IR1 and IR2) and displays the stability locus on a prominent loop thus making it available for plasmid clustering. Our results form the first global map of chromosomal interactions in a eukaryotic nucleus and demonstrate the highly connected nature of the yeast genome. These results have significant implications for understanding eukaryotic genome organization.
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Affiliation(s)
- C D M Rodley
- Institute of Molecular Biosciences, Massey University, Private Bag 102 904, Albany, NSMC, Auckland, New Zealand
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Ghosh SK, Hajra S, Jayaram M. Faithful segregation of the multicopy yeast plasmid through cohesin-mediated recognition of sisters. Proc Natl Acad Sci U S A 2007; 104:13034-9. [PMID: 17670945 PMCID: PMC1941829 DOI: 10.1073/pnas.0702996104] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Indexed: 11/18/2022] Open
Abstract
The 2-microm yeast plasmid, a benign high-copy nuclear parasite, propagates itself with nearly the same fidelity as the chromosomes of its host. Equal plasmid segregation is absolutely dependent on the cohesin complex assembled at the plasmid partitioning locus STB. However, the mechanism of cohesin action in the context of multiple plasmid copies, resident within two separate clusters after DNA replication, is unknown. By using "single-copy" derivatives of the 2-microm plasmid, we demonstrate that recruitment of cohesin at STB during S phase indeed translates into cohesion between plasmid molecules. Through binary fluorescence tagging, we reveal that segregation of replicated plasmids occurs in a sister-to-sister fashion. Thus, cohesin serves the same fundamental purpose in plasmid and chromosome segregation.
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Affiliation(s)
- Santanu K. Ghosh
- Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712
| | - Sujata Hajra
- Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712
| | - Makkuni Jayaram
- Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712
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Abstract
At the foundation of all eukaryotic kinetochores is a unique histone variant, known as CenH3 (centromere histone H3). We are starting to identify the histone chaperones responsible for CenH3 deposition at centromere DNA, and the mechanisms that restrict CenH3 from chromosome arms. The specialized nucleosome that contains CenH3 in place of canonical histone H3 lies at the interface between microtubules and chromosomes and directs kinetochore protein assembly. By contrast, pericentric chromatin is highly elastic and can stretch or recoil in response to microtubule shortening or growth in mitosis. The variety in histone modification is likely to play a key role in regulating the behavior of these distinct chromatin domains.
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Affiliation(s)
- Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA.
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