Increasing the homologous recombination efficiency of eukaryotic microorganisms for enhanced genome engineering

2019 ◽  
Vol 103 (11) ◽  
pp. 4313-4324 ◽  
Author(s):  
Ying Ding ◽  
Kai-Feng Wang ◽  
Wei-Jian Wang ◽  
Yi-Rong Ma ◽  
Tian-Qiong Shi ◽  
...  
2021 ◽  
Author(s):  
Manning Y. Huang ◽  
Meenakshi B. Joshi ◽  
Michael J Boucher ◽  
Sujin Lee ◽  
Liza C. Loza ◽  
...  

Cryptococcus neoformans, the most common cause of fungal meningitis, is a basidiomycete haploid budding yeast with a complete sexual cycle. Genome modification by homologous recombination is feasible using biolistic transformation and long homology arms, but the method is arduous and unreliable. Recently, multiple groups have reported the use of CRISPR-Cas9 as an alternative to biolistics, but long homology arms are still necessary, limiting the utility of this method. Since the S. pyogenes Cas9 derivatives used in prior studies were not optimized for expression in C. neoformans, we designed, synthesized, and tested a fully C. neoformans-optimized Cas9. We found that a Cas9 harboring only common C. neoformans codons and a consensus C. neoformans intron together with a TEF1 promoter and terminator and a nuclear localization signal (C. neoformans-optimized CAS9 or 'CnoCAS9') reliably enabled genome editing in the widely-used KN99α C. neoformans strain. Furthermore, editing was accomplished using donors harboring short (50 bp) homology arms attached to marker DNAs produced with synthetic oligonucleotides and PCR amplification. We also demonstrated that prior stable integration of CnoCAS9 further enhances both transformation and homologous recombination efficiency; importantly, this manipulation does not impact virulence in animals. We also implemented a universal tagging module harboring a codon-optimized fluorescent protein (mNeonGreen) and a tandem Calmodulin Binding Peptide-2X FLAG Tag that allows for both localization and purification studies of proteins for which the corresponding genes are modified by short homology-directed recombination. These tools enable short-homology genome engineering in C. neoformans.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Anmoldeep Randhawa ◽  
Nandita Pasari ◽  
Tulika Sinha ◽  
Mayank Gupta ◽  
Anju M. Nair ◽  
...  

Abstract Background Penicillium funiculosum NCIM1228 is a non-model filamentous fungus that produces high-quality secretome for lignocellulosic biomass saccharification. Despite having desirable traits to be an industrial workhorse, P. funiculosum has been underestimated due to a lack of reliable genetic engineering tools. Tolerance towards common fungal antibiotics had been one of the major hindrances towards development of reliable transformation tools against the non-model fungi. In this study, we sought to understand the mechanism of drug tolerance of P. funiculosum and the provision to counter it. We then attempted to identify a robust method of transformation for genome engineering of this fungus. Results Penicillium funiculosum showed a high degree of drug tolerance towards hygromycin, zeocin and nourseothricin, thereby hindering their use as selectable markers to obtain recombinant transformants. Transcriptome analysis suggested a high level expression of efflux pumps belonging to ABC and MFS family, especially when complex carbon was used in growth media. Antibiotic selection medium was optimized using a combination of efflux pump inhibitors and suitable carbon source to prevent drug tolerability. Protoplast-mediated and Agrobacterium-mediated transformation were attempted for identifying efficiencies of linear and circular DNA in performing genetic manipulation. After finding Ti-plasmid-based Agrobacterium-mediated transformation more suitable for P. funiculosum, we improvised the system to achieve random and homologous recombination-based gene integration and deletion, respectively. We found single-copy random integration of the T-DNA cassette and could achieve 60% efficiency in homologous recombination-based gene deletions. A faster, plasmid-free, and protoplast-based CRISPR/Cas9 gene-editing system was also developed for P. funiculosum. To show its utility in P. funiculosum, we deleted the gene coding for the most abundant cellulase Cellobiohydrolase I (CBH1) using a pair of sgRNA directed towards both ends of cbh1 open reading frame. Functional analysis of ∆cbh1 strain revealed its essentiality for the cellulolytic trait of P. funiculosum secretome. Conclusions In this study, we addressed drug tolerability of P. funiculosum and developed an optimized toolkit for its genome modification. Hence, we set the foundation for gene function analysis and further genetic improvements of P. funiculosum using both traditional and advanced methods.


2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Daniel Sommer ◽  
Annika E. Peters ◽  
Tristan Wirtz ◽  
Maren Mai ◽  
Justus Ackermann ◽  
...  

Mycoscience ◽  
2010 ◽  
Vol 51 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Kiminori Shimizu ◽  
Hao-Man Li ◽  
Eric V. Virtudazo ◽  
Akira Watanabe ◽  
Katsuhiko Kamei ◽  
...  

2016 ◽  
Author(s):  
Julie E. Norville ◽  
Cameron L. Gardner ◽  
Eduardo Aponte ◽  
Conor K. Camplisson ◽  
Alexandra Gonzales ◽  
...  

AbstractThe large potential of radically recoded organisms (RROs) in medicine and industry depends on improved technologies for efficient assembly and testing of recoded genomes for biosafety and functionality. Here we describe a next generation platform for conjugative assembly genome engineering, termed CAGE 2.0, that enables the scarless integration of large synthetically recoded E. coli segments at isogenic and adjacent genomic loci. A stable tdk dual selective marker is employed to facilitate cyclical assembly and removal of attachment sites used for targeted segment delivery by sitespecific recombination. Bypassing the need for vector transformation harnesses the multi Mb capacity of CAGE, while minimizing artifacts associated with RecA-mediated homologous recombination. Our method expands the genome engineering toolkit for radical modification across many organisms and recombinase-mediated cassette exchange (RMCE).


2018 ◽  
Vol 149 (3) ◽  
pp. 575-584 ◽  
Author(s):  
Andrew J. Wilson ◽  
Matthew Stubbs ◽  
Phillip Liu ◽  
Bruce Ruggeri ◽  
Dineo Khabele

2007 ◽  
Vol 58 (Supplement 1) ◽  
pp. 1-10
Author(s):  
B. Csörgő ◽  
G. Pósfai

2015 ◽  
Vol 4 (11) ◽  
pp. 1176-1185 ◽  
Author(s):  
Gur Pines ◽  
Emily F. Freed ◽  
James D. Winkler ◽  
Ryan T. Gill

genesis ◽  
2018 ◽  
Vol 56 (5) ◽  
pp. e23212 ◽  
Author(s):  
Sandra Acosta ◽  
Luciano Fiore ◽  
Isabel Anna Carota ◽  
Guillermo Oliver

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