Author response: Explosive mutation accumulation triggered by heterozygous human Pol ε proofreading-deficiency is driven by suppression of mismatch repair

Hodel, Karl P.; Borja, Richard de; Henninger, Erin; Campbell, Brittany; Ungerleider, Nathan; Light, Nicholas; Wu, Tong; LeCompte, Kimberly G.; Göksenin, A. Yasemin; Bunnell, Bruce A.; Tabori, Uri; Pursell, Zachary F.

doi:10.7554/elife.32692.034

Cited by 2 publications

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“…These results suggest that the heterologous mutations in AgMSH2, AgMSH3 and AgMSH6 may compromise the DNA mismatch repair pathway and contribute to the maintenance of DNA mismatches and accumulation of heterologous mutations in the genome of A. gossypii during disparity mutagenesis and rapid evolution of A. gossypii to the riboflavinoverproducing mutant MT strain. Previous papers have shown that heterologous mutations of the ScMSH2 gene showed mutator phenotypes in diploid yeasts and suppression of the mismatch repair pathway and proofreading-deficient DNA polymerase e in human cells, leading to the accumulation of numerous mutations [54,55]. However, the riboflavin production level in MT was stable during 14 passages [13].…”

Section: It Was Previously Reported That Riboflavin Production In a mentioning

confidence: 99%

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

Kato

Azegami

Yokomori

et al. 2020

Preprint

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Background: Ashbya gossypii naturally overproduces riboflavin and has been utilized for industrial riboflavin production. To improve riboflavin production, various approaches have been developed. In this study, to investigate the change in metabolism of a riboflavin-overproducing mutant, namely, the W122032 strain (MT strain) that was isolated by disparity mutagenesis, genomic analysis was carried out. Results: In the genomic analysis, 33 homozygous and 1377 heterozygous mutations in the coding sequences of the genome of MT strain were detected. Among these heterozygous mutations, the proportion of mutated reads in each gene was different, ranging from 21 to 75%. These results suggest that the MT strain may contain multiple nuclei containing different mutations. We tried to isolate haploid spores from the MT strain to prove its ploidy, but this strain did not sporulate under the conditions tested. Heterozygous mutations detected in genes which are important for sporulation likely contribute to the sporulation deficiency of the MT strain. Homozygous and heterozygous mutations were found in genes encoding enzymes involved in amino acid metabolism, the TCA cycle, purine and pyrimidine nucleotide metabolism and the DNA mismatch repair system. One homozygous mutation in AgILV2 gene encoding acetohydroxyacid synthase, which is also a flavoprotein in mitochondria, was found. Gene ontology (GO) enrichment analysis showed heterozygous mutations in all 22 DNA helicase genes and genes involved in oxidation-reduction process. Conclusion: This study suggests that oxidative stress and the aging of cells were involved in the riboflavin over-production in A. gossypii riboflavin over-producing mutant and provides new insights into riboflavin production in A. gossypii and the usefulness of disparity mutagenesis for the creation of new types of mutants for metabolic engineering.

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Section: It Was Previously Reported That Riboflavin Production In a mentioning

confidence: 99%

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

Kato

Azegami

Yokomori

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…These results suggest that the heterologous mutations in AgMSH2, AgMSH3 and AgMSH6 may compromise the DNA mismatch repair pathway and contribute to the maintenance of DNA mismatches and accumulation of heterologous mutations in the genome of A.gossypii during disparity mutagenesis and rapid evolution of A. gossypii to the riboflavinoverproducing mutant MT strain. Previous papers have shown that heterologous mutations of the ScMSH2 gene showed mutator phenotypes in diploid yeasts and suppression of the mismatch repair pathway and proofreading-deficient DNA polymerase e in human cells, leading to the accumulation of numerous mutations[52,53]. However, the riboflavin production level in MT was stable during 14 passages[13].…”

mentioning

confidence: 99%

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

Kato

Azegami

Yokomori

et al. 2019

Preprint

View full text Add to dashboard Cite

Background: Ashbya gossypii naturally overproduces riboflavin and has been utilized for industrial riboflavin production. To improve riboflavin production, various approaches have been developed. In this study, to investigate the change in metabolism of a riboflavin-overproducing mutant, namely, the W122032 strain (MT strain) that was isolated by disparity mutagenesis, genomic analysis was carried out. Results: In the genomic analysis, 33 homozygous and 1377 heterozygous mutations were detected. Among these heterozygous mutations, the proportion of mutated reads in each gene was different, ranging from 21 to 75%. We tried to isolate haploid spores from the MT strain to prove it ploidy, but these spores were never isolated. These results suggest that the MT strain may contain multiple nuclei containing different mutations to survive without any spores. Homozygous and heterozygous mutations were found in genes encoding enzymes involved in amino acid metabolism, the TCA cycle, purine and pyrimidine nucleotide metabolism and the DNA mismatch repair system. Especially, genes encoding enzymes in mitochondria had many homozygous and heterozygous mutations intensively. These results suggest that the overproduction of riboflavin in the MT strain may be associated with mitochondrial dysfunction. Conclusion: This study provides new insights into riboflavin production in A. gossypii and the usefulness of disparity mutagenesis for the creation of new types of mutants for metabolic engineering.

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Author response: Explosive mutation accumulation triggered by heterozygous human Pol ε proofreading-deficiency is driven by suppression of mismatch repair

Cited by 2 publications

References 0 publications

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

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