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Wang Q, Gong Y, He Y, Xin Y, Lv N, Du X, Li Y, Jeong BR, Xu J. Genome engineering of Nannochloropsis with hundred-kilobase fragment deletions by Cas9 cleavages. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1148-1162. [PMID: 33719095 DOI: 10.1111/tpj.15227] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/21/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Industrial microalgae are promising photosynthetic cell factories, yet tools for large-scale targeted genome engineering are limited. Here for the model industrial oleaginous microalga Nannochloropsis oceanica, we established a method to precisely and serially delete large genome fragments of ~100 kb from its 30.01 Mb nuclear genome. We started by identifying the 'non-essential' chromosomal regions (i.e. low expression region or LER) based on minimal gene expression under N-replete and N-depleted conditions. The largest such LER (LER1) is ~98 kb in size, located near the telomere of the 502.09-kb-long Chromosome 30 (Chr 30). We deleted 81 kb and further distal and proximal deletions of up to 110 kb (21.9% of Chr 30) in LER1 by dual targeting the boundaries with the episome-based CRISPR/Cas9 system. The telomere-deletion mutants showed normal telomeres consisting of CCCTAA repeats, revealing telomere regeneration capability after losing the distal part of Chr 30. Interestingly, the deletions caused no significant alteration in growth, lipid production or photosynthesis (transcript-abundance change for < 3% genes under N depletion). We also achieved double-deletion of both LER1 and LER2 (from Chr 9) that total ~214 kb at maximum, which can result in slightly higher growth rate and biomass productivity than the wild-type. Therefore, loss of the large, yet 'non-essential' regions does not necessarily sacrifice important traits. Such serial targeted deletions of large genomic regions had not been previously reported in microalgae, and will accelerate crafting minimal genomes as chassis for photosynthetic production.
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Affiliation(s)
- Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanhai Gong
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuehui He
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Nana Lv
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuefeng Du
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yun Li
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Byeong-Ryool Jeong
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Stabilization of mini-chromosome segregation during mitotic growth by overexpression of YCR041W and its application to chromosome engineering in Saccharomyces cerevisiae. J Biosci Bioeng 2014; 119:526-31. [PMID: 25454064 DOI: 10.1016/j.jbiosc.2014.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/07/2014] [Accepted: 10/10/2014] [Indexed: 11/22/2022]
Abstract
Chromosome engineering enables large-scale genome manipulation and can be used as a novel technology for breeding of yeasts. PCR-mediated chromosome splitting (PCS) offers a powerful tool for chromosome engineering by enabling a yeast chromosome to be split at any desired site. By applying PCS, a huge variety of chromosome combinations can be created and the best strain under specific conditions can be selected-a technology that we have called genome reorganization. Once the optimal strain is obtained, chromosome constitutions need to be maintained stably; however, mini-chromosomes of less than 50 kb are at relatively high frequency lost during cultivation. To overcome this problem, in this study we screened for multicopy suppressors of the high loss of mini-chromosomes by using a multicopy genomic library of Saccharomyces cerevisiae. We identified a novel gene, YCR041W, that stabilizes mini-chromosomes. The translational product of YCR041W was suggested to play an important role in increasing stability for mini-chromosome maintenance, probably by decreasing the rate of loss during mitotic cell division. The stabilization of mini-chromosomes conferred by YCR041W overexpression was completely dependent on the silencing protein Sir4, suggesting that a process related to telomere function might be involved in mini-chromosome stabilization. Overexpression of YCR041W stabilized not only a yeast artificial chromosome vector, but also a mini-chromosome derived from a natural chromosome. Taking these results together, we propose that YCR041W overexpression can be used as a novel chromosome engineering tool for controlling mini-chromosome maintenance and loss.
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Large-scale genome reorganization in Saccharomyces cerevisiae through combinatorial loss of mini-chromosomes. J Biosci Bioeng 2012; 113:675-82. [PMID: 22382015 DOI: 10.1016/j.jbiosc.2012.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 12/15/2022]
Abstract
A highly efficient technique, termed PCR-mediated chromosome splitting (PCS), was used to create cells containing a variety of genomic constitutions in a haploid strain of Saccharomyces cerevisiae. Using PCS, we constructed two haploid strains, ZN92 and SH6484, that carry multiple mini-chromosomes. In strain ZN92, chromosomes IV and XI were split into 16 derivative chromosomes, seven of which had no known essential genes. Strain SH6484 was constructed to have 14 mini-chromosomes carrying only non-essential genes by splitting chromosomes I, II, III, VIII, XI, XIII, XIV, XV, and XVI. Both strains were cultured under defined nutrient conditions and analyzed for combinatorial loss of mini-chromosomes. During culture, cells with various combinations of mini-chromosomes arose, indicating that genomic reorganization could be achieved by splitting chromosomes to generate mini-chromosomes followed by their combinatorial loss. We found that although non-essential mini-chromosomes were lost in various combinations in ZN92, one mini-chromosome (18kb) that harbored 12 genes was not lost. This finding suggests that the loss of some combination of these 12 non-essential genes might result in synthetic lethality. We also found examples of genome-wide amplifications induced by mini-chromosome loss. In SH6484, the mitochondrial genome, as well as the copy number of genomic regions not contained in the mini-chromosomes, was specifically amplified. We conclude that PCS allows for genomic reorganization, in terms of both combinations of mini-chromosomes and gene dosage, and we suggest that PCS could be useful for the efficient production of desired compounds by generating yeast strains with optimized genomic constitutions.
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Sugiyama M, Yamagishi K, Kim YH, Kaneko Y, Nishizawa M, Harashima S. Advances in molecular methods to alter chromosomes and genome in the yeast Saccharomyces cerevisiae. Appl Microbiol Biotechnol 2009; 84:1045-52. [PMID: 19685240 DOI: 10.1007/s00253-009-2144-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 07/12/2009] [Accepted: 07/12/2009] [Indexed: 10/20/2022]
Abstract
A fundamental issue in biotechnology is how to breed useful strains of microorganisms for efficient production of valuable biomaterials. On-going and more recent developments in gene manipulation technologies and chromosomal and genomic modifications in particular have facilitated important contributions in this area. "Chromosome manipulation technology" as an outgrowth of "gene manipulation technology" may provide opportunities for creating novel strains of organisms with a variety of genomic constitutions. A simple and rapid chromosome splitting technology called "PCR-mediated chromosome splitting" (PCS) that we recently developed has made it possible to manipulate chromosomes and genomes on a large scale in an industrially important microorganism, Saccharomyces cerevisiae. This paper focuses on recent advances in molecular methods for altering chromosomes and genome in S. cerevisiae featuring chromosome splitting technology. These advances in introducing large-scale genomic modifications are expected to accelerate the breeding of novel strains for biotechnological purposes, and to reveal functions of presently uncharacterized chromosomal regions in S. cerevisiae and other organisms.
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Affiliation(s)
- Minetaka Sugiyama
- Department of Biotechnology, Osaka University, Yamadaoka, Suita-shi, Japan
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Kim YH, Ishikawa D, Ha HP, Sugiyama M, Kaneko Y, Harashima S. Chromosome XII context is important for rDNA function in yeast. Nucleic Acids Res 2006; 34:2914-24. [PMID: 16738130 PMCID: PMC1474064 DOI: 10.1093/nar/gkl293] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2005] [Revised: 09/02/2005] [Accepted: 04/06/2006] [Indexed: 11/13/2022] Open
Abstract
The rDNA cluster in Saccharomyces cerevisiae is located 450 kb from the left end and 610 kb from the right end of chromosome XII and consists of approximately 150 tandemly repeated copies of a 9.1 kb rDNA unit. To explore the biological significance of this specific chromosomal context, chromosome XII was split at both sides of the rDNA cluster and strains harboring deleted variants of chromosome XII consisting of 450 kb, 1500 kb (rDNA cluster only) and 610 kb were created. In the strain harboring the 1500 kb variant of chromosome XII consisting solely of rDNA, the size of the rDNA cluster was found to decrease as a result of a decrease in rDNA copy number. The frequency of silencing of URA3 inserted within the rDNA locus was found to be greater than in a wild-type strain. The localization and morphology of the nucleolus was also affected such that a single and occasionally (6-12% frequency) two foci for Nop1p and a rounded nucleolus were observed, whereas a typical crescent-shaped nucleolar structure was seen in the wild-type strain. Notably, strains harboring the 450 kb chromosome XII variant and/or the 1500 kb variant consisting solely of rDNA had shorter life spans than wild type and also accumulated extrachromosomal rDNA circles. These observations suggest that the context of chromosome XII plays an important role in maintaining a constant rDNA copy number and in physiological processes related to rDNA function in S.cerevisiae.
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Affiliation(s)
- Yeon-Hee Kim
- Department of Biotechnology, Graduate School of Engineering, Osaka University2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Daisuke Ishikawa
- Department of Biotechnology, Graduate School of Engineering, Osaka University2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ho Phu Ha
- Department of Biotechnology, Graduate School of Engineering, Osaka University2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Minetaka Sugiyama
- Department of Biotechnology, Graduate School of Engineering, Osaka University2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshinobu Kaneko
- Department of Biotechnology, Graduate School of Engineering, Osaka University2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Satoshi Harashima
- Department of Biotechnology, Graduate School of Engineering, Osaka University2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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Kim Y, Sugiyama M, Yamagishi K, Kaneko Y, Fukui K, Kobayashi A, Harashima S. A versatile and general splitting technology for generating targeted YAC subclones. Appl Microbiol Biotechnol 2005; 69:65-70. [PMID: 15864580 DOI: 10.1007/s00253-005-1970-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 03/12/2005] [Accepted: 03/20/2005] [Indexed: 10/25/2022]
Abstract
Yeast artificial chromosomes (YAC) splitting technology was developed as a means to subclone any desired region of eukaryotic chromosomes from one YAC into new YACs. In the present study, the conventional YAC splitting technology was improved by incorporating PCR-mediated chromosome splitting technique and by adding autonomously replicating sequence (ARS) to the system. To demonstrate the performance of the improved method, a 60-kb region from within a 590-kb YAC (clone CIC9e2 from Arabidopsis thaliana chromosome 5) that could not be subcloned using the original method was split to convert into a replicating YAC. Two template plasmids, pSK-KCA and pSKCLY, were used to generate two splitting fragments by PCR. Two splitting fragments consisted of telomeric (C(4)A(2))(6) repeats, 400-bp target region, CEN4, H4ARS and Km(r) (selective marker for plant transformants), or CgLEU2. These splitting fragments were introduced into Saccharomyces cerevisiae harboring the 100-kb split YAC generated by splitting of the 590-kb YAC and containing the 60-kb region. Among 12 Leu(+) transformants, four exhibited the expected karyotype in which two newly split 40- and 60-kb chromosomes were generated. These results demonstrate that the improved method can convert a targeted region of a eukaryotic chromosome within a YAC into a replicating YAC.
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Affiliation(s)
- Yeonhee Kim
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita-shi, Osaka 565-0871, Japan
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