Evidence map›Paper›PMID 39407321›Full record

ArticleFungal biology and biotechnology2024

Competition between homologous chromosomal DNA and exogenous donor DNA to repair CRISPR/Cas9-induced double-strand breaks in Aspergillus  niger.

Selina Forrer, Mark Arentshorst, Prajeesh Koolth Valappil, Jaap Visser, Arthur F J Ram

Abstract read
In one paragraph

Article in Fungal biology and biotechnology, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Selina Forrer *Institute Biology Leiden, Microbial Sciences, Fungal Genetics and Biotechnology, Leiden University, Sylviusweg 72, Leiden, 2333 BE, The Netherlands.
Mark Arentshorst *Institute Biology Leiden, Microbial Sciences, Fungal Genetics and Biotechnology, Leiden University, Sylviusweg 72, Leiden, 2333 BE, The Netherlands.
Prajeesh Koolth ValappilInstitute Biology Leiden, Microbial Sciences, Fungal Genetics and Biotechnology, Leiden University, Sylviusweg 72, Leiden, 2333 BE, The Netherlands.
Jaap VisserInstitute Biology Leiden, Microbial Sciences, Fungal Genetics and Biotechnology, Leiden University, Sylviusweg 72, Leiden, 2333 BE, The Netherlands.
Arthur F J RamInstitute Biology Leiden, Microbial Sciences, Fungal Genetics and Biotechnology, Leiden University, Sylviusweg 72, Leiden, 2333 BE, The Netherlands. a.f.j.ram@biology.leidenuniv.nl.

Funding

Nederlandse Organisatie voor Wetenschappelijk Onderzoek ENPPS.LIFT.019.037
6 · The paper itself

Abstract

backgroundAspergillus niger is well-known for its high protein secretion capacity and therefore an important cell factory for homologous and heterologous protein production. The use of a strong promoter and multiple gene copies are commonly used strategies to increase the gene expression and protein production of the gene of interest (GOI). We recently presented a two-step CRISPR/Cas9-mediated approach in which glucoamylase (glaA) landing sites (GLSs) are introduced at predetermined sites in the genome (step 1), which are subsequently filled with copies of the GOI (step 2) to achieve high expression of the GOI.

resultsHere we show that in a ku70 defective A. niger strain (Δku70), thereby excluding non-homologous end joining (NHEJ) as a mechanism to repair double-stranded DNA breaks (DSBs), the chromosomal glaA locus or homologous GLSs can be used to repair Cas9-induced DSBs, thereby competing with the integration of the donor DNA containing the GOI. In the absence of exogenously added donor DNA, the DSBs are repaired with homologous chromosomal DNA located on other chromosomes (inter-chromosomal repair) or, with higher efficiency, by a homologous DNA fragment located on the same chromosome (intra-chromosomal repair). Single copy inter-chromosomal homology-based DNA repair was found to occur in 13-20% of the transformants while 80-87% of the transformants were repaired by exogenously added donor DNA. The efficiency of chromosomal repair was dependent on the copy number of the potential donor DNA sequences in the genome. The presence of five homologous DNA sequences, resulted in an increased number (35-61%) of the transformants repaired by chromosomal DNA. The efficiency of intra-chromosomal homology based DSB repair in the absence of donor DNA was found to be highly preferred (85-90%) over inter-chromosomal repair. Intra-chromosomal repair was also found to be the preferred way of DNA repair in the presence of donor DNA and was found to be locus-dependent.

conclusionThe awareness that homologous chromosomal DNA repair can compete with donor DNA to repair DSB and thereby affecting the efficiency of multicopy strain construction using CRISPR/Cas9-mediated genome editing is an important consideration to take into account in industrial strain design.

Indexed as

Aspergillus nigerCell factoryCRISPR/Cas9 genome editingDNA repairMulticopy strainsProtein production

Identifiers

PMID39407321
PMCPMC11481784

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