Maintenance of Yeast Genome Integrity by RecQ Family DNA Helicases

Gupta, Sonia Vidushi; Schmidt, Kristina

doi:10.3390/genes11020205

Cited by 20 publications

(9 citation statements)

References 244 publications

(330 reference statements)

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“…Moreover, the mcm7-10R rrm3Δ pif1Δ triple mutant is also inviable (Fig 5B). In contrast, other replication fork associated helicases such as Chl1 (Samora et al , 2016; Skibbens, 2004; Srinivasan et al , 2020), Srs2 (Arbel et al , 2020; Crickard & Greene, 2019; Lehmann et al , 2020) and the Sgs1 orthologue of human BLM helicase (Gupta & Schmidt, 2020; Simmons et al , 2021) were not required for the viability of mcm7-10R (Fig EV4B-D). These findings indicate that Pif1-family helicases are important for cell viability in response to defects in CMG helicase disassembly.…”

Section: Resultsmentioning

confidence: 97%

CMG helicase disassembly is essential and driven by two pathways in budding yeast

Rivera,

Deegan,

Labib

2024

Preprint

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The CMG helicase is the metastable core of the eukaryotic replisome and is ubiquitylated and disassembled during DNA replication termination. Fungi and animals use different enzymes to ubiquitylate the Mcm7 subunit of CMG, indicating that CMG ubiquitylation arose repeatedly during eukaryotic evolution. Until now, it was unclear whether cells also have ubiquitin-independent pathways for helicase disassembly and whether CMG disassembly is essential for cell viability. Using reconstituted assays with budding yeast CMG, we generated the mcm7-10R allele that compromises ubiquitylation by SCFDia2. mcm7-10R delays helicase disassembly in vivo, driving genome instability in the next cell cycle. These data indicate that defective CMG ubiquitylation explains the major phenotypes of cells lacking Dia2. Notably, the viability of mcm7-10R and dia2∆ is dependent upon the related Rrm3 and Pif1 DNA helicases that have orthologues in all eukaryotes. We show that Rrm3 acts during S-phase to disassemble old CMG complexes from the previous cell cycle. These findings indicate that CMG disassembly is essential in yeast cells and suggest that Pif1-family helicases might have mediated CMG disassembly in ancestral eukaryotes.

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Section: Resultsmentioning

confidence: 97%

CMG helicase disassembly is essential and driven by two pathways in budding yeast

Rivera,

Deegan,

Labib

2024

Preprint

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“…Domain organization and homology modelling. (A) Schematic representation of domain organization in Escherichia coli RecQ [4], human RECQ1 [5], human WRN [77], Saccharomyces cerevisiae Sgs1 [78], human BLM [8] and LdRECQb (as predicted by Pfam analysis and multiple sequence alignment). The amino acid residue numbers represent the boundary of each domain.…”

Section: Resultsmentioning

confidence: 99%

The catalytic core of Leishmania donovani RECQ helicase unwinds a wide spectrum of DNA substrates and is stimulated by replication protein A

et al. 2021

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RecQ helicases are superfamily 2 (SF2) DNA helicases that unwind a wide spectrum of complex DNA structures in a 3 0 to 5 0 direction and are involved in maintaining genome stability. RecQ helicases from protozoan parasites have gained significant interest in recent times because of their involvement in cellular DNA repair pathways, making them important targets for drug development. In this study, we report biophysical and biochemical characterization of the catalytic core of a RecQ helicase from hemoflagellate protozoan parasite Leishmania donovani. Among the two putative RecQ helicases identified in L. donovani, we cloned, overexpressed and purified the catalytic core of LdRECQb. The catalytic core was found to be very efficient in unwinding a wide variety of DNA substrates like forked duplex, 3 0 tailed duplex and Holliday junction DNA. Interestingly, the helicase core also unwound blunt duplex with slightly less efficiency. The enzyme exhibited high level of DNA-stimulated ATPase activity with preferential stimulation by forked duplex, Holliday junction and 3 0 tailed duplex. Walker A motif lysine mutation severely affected the ATPase activity and significantly affected unwinding activity. Like many other RecQ helicases, L. donovani RECQb also possesses strand annealing activity. Unwinding of longer DNA substrates by LdRECQb catalytic core was found to be stimulated in the presence of replication protein A (LdRPA-1) from L. donovani. Detailed biochemical characterization and comparison of kinetic parameters indicate that L. donovani RECQb shares considerable functional similarity with human Bloom syndrome helicase.

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“…Recent studies demonstrate that Hrq1 functions during NER to repair cisplatin-induced DNA lesions [44][45][46][47]. However, there are conflicting studies as to whether Hrq1 also has a role in PRR [44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Hrq1/RECQL4 regulation is critical for preventing aberrant recombination during DNA intrastrand crosslink repair and is upregulated in breast cancer

Luong

Li²,

Priedigkeit³

et al. 2022

PLoS Genet

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Human RECQL4 is a member of the RecQ family of DNA helicases and functions during DNA replication and repair. RECQL4 mutations are associated with developmental defects and cancer. Although RECQL4 mutations lead to disease, RECQL4 overexpression is also observed in cancer, including breast and prostate. Thus, tight regulation of RECQL4 protein levels is crucial for genome stability. Because mammalian RECQL4 is essential, how cells regulate RECQL4 protein levels is largely unknown. Utilizing budding yeast, we investigated the RECQL4 homolog, HRQ1, during DNA crosslink repair. We find that Hrq1 functions in the error-free template switching pathway to mediate DNA intrastrand crosslink repair. Although Hrq1 mediates repair of cisplatin-induced lesions, it is paradoxically degraded by the proteasome following cisplatin treatment. By identifying the targeted lysine residues, we show that preventing Hrq1 degradation results in increased recombination and mutagenesis. Like yeast, human RECQL4 is similarly degraded upon exposure to crosslinking agents. Furthermore, over-expression of RECQL4 results in increased RAD51 foci, which is dependent on its helicase activity. Using bioinformatic analysis, we observe that RECQL4 overexpression correlates with increased recombination and mutations. Overall, our study uncovers a role for Hrq1/RECQL4 in DNA intrastrand crosslink repair and provides further insight how misregulation of RECQL4 can promote genomic instability, a cancer hallmark.

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Maintenance of Yeast Genome Integrity by RecQ Family DNA Helicases

Cited by 20 publications

References 244 publications

CMG helicase disassembly is essential and driven by two pathways in budding yeast

CMG helicase disassembly is essential and driven by two pathways in budding yeast

The catalytic core of Leishmania donovani RECQ helicase unwinds a wide spectrum of DNA substrates and is stimulated by replication protein A

Hrq1/RECQL4 regulation is critical for preventing aberrant recombination during DNA intrastrand crosslink repair and is upregulated in breast cancer

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