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Eekhout T, Pedroza-Garcia JA, Kalhorzadeh P, De Jaeger G, De Veylder L. A Mutation in DNA Polymerase α Rescues WEE1KO Sensitivity to HU. Int J Mol Sci 2021; 22:9409. [PMID: 34502313 PMCID: PMC8430855 DOI: 10.3390/ijms22179409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022] Open
Abstract
During DNA replication, the WEE1 kinase is responsible for safeguarding genomic integrity by phosphorylating and thus inhibiting cyclin-dependent kinases (CDKs), which are the driving force of the cell cycle. Consequentially, wee1 mutant plants fail to respond properly to problems arising during DNA replication and are hypersensitive to replication stress. Here, we report the identification of the polα-2 mutant, mutated in the catalytic subunit of DNA polymerase α, as a suppressor mutant of wee1. The mutated protein appears to be less stable, causing a loss of interaction with its subunits and resulting in a prolonged S-phase.
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Affiliation(s)
- Thomas Eekhout
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium; (T.E.); (J.A.P.-G.); (P.K.); (G.D.J.)
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - José Antonio Pedroza-Garcia
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium; (T.E.); (J.A.P.-G.); (P.K.); (G.D.J.)
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Pooneh Kalhorzadeh
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium; (T.E.); (J.A.P.-G.); (P.K.); (G.D.J.)
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium; (T.E.); (J.A.P.-G.); (P.K.); (G.D.J.)
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Lieven De Veylder
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium; (T.E.); (J.A.P.-G.); (P.K.); (G.D.J.)
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
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Eekhout T, Dvorackova M, Pedroza Garcia JA, Nespor Dadejova M, Kalhorzadeh P, Van den Daele H, Vercauteren I, Fajkus J, De Veylder L. G2/M-checkpoint activation in fasciata1 rescues an aberrant S-phase checkpoint but causes genome instability. PLANT PHYSIOLOGY 2021; 186:1893-1907. [PMID: 34618100 PMCID: PMC8331141 DOI: 10.1093/plphys/kiab201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/05/2021] [Indexed: 05/13/2023]
Abstract
The WEE1 and ATM AND RAD3-RELATED (ATR) kinases are important regulators of the plant intra-S-phase checkpoint; consequently, WEE1KO and ATRKO roots are hypersensitive to replication-inhibitory drugs. Here, we report on a loss-of-function mutant allele of the FASCIATA1 (FAS1) subunit of the chromatin assembly factor 1 (CAF-1) complex that suppresses the phenotype of WEE1- or ATR-deficient Arabidopsis (Arabidopsis thaliana) plants. We demonstrate that lack of FAS1 activity results in the activation of an ATAXIA TELANGIECTASIA MUTATED (ATM)- and SUPPRESSOR OF GAMMA-RESPONSE 1 (SOG1)-mediated G2/M-arrest that renders the ATR and WEE1 checkpoint regulators redundant. This ATM activation accounts for the telomere erosion and loss of ribosomal DNA that are described for fas1 plants. Knocking out SOG1 in the fas1 wee1 background restores replication stress sensitivity, demonstrating that SOG1 is an important secondary checkpoint regulator in plants that fail to activate the intra-S-phase checkpoint.
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Affiliation(s)
- Thomas Eekhout
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Martina Dvorackova
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic
| | - José Antonio Pedroza Garcia
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Martina Nespor Dadejova
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic
| | - Pooneh Kalhorzadeh
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Hilde Van den Daele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Ilse Vercauteren
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Jiri Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic
| | - Lieven De Veylder
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
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Kuciński J, Chamera S, Kmera A, Rowley MJ, Fujii S, Khurana P, Nowotny M, Wierzbicki AT. Evolutionary History and Activity of RNase H1-Like Proteins in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2020; 61:1107-1119. [PMID: 32191307 PMCID: PMC7295395 DOI: 10.1093/pcp/pcaa040] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/14/2020] [Indexed: 06/01/2023]
Abstract
RNase H1 is an endonuclease specific toward the RNA strand of RNA:DNA hybrids. Members of this protein family are present in most living organisms and are essential for removing RNA that base pairs with DNA. It prevents detrimental effects of RNA:DNA hybrids and is involved in several biological processes. Arabidopsis thaliana has been previously shown to contain three genes encoding RNase H1 proteins that localize to three distinct cellular compartments. We show that these genes originate from two gene duplication events. One occurred in the common ancestor of dicots and produced nuclear and organellar RNase H1 paralogs. Second duplication occurred in the common ancestor of Brassicaceae and produced mitochondrial- and plastid-localized proteins. These proteins have the canonical RNase H1 activity, which requires at least four ribonucleotides for endonucleolytic digestion. Analysis of mutants in the RNase H1 genes revealed that the nuclear RNH1A and mitochondrial RNH1B are dispensable for development under normal growth conditions. However, the presence of at least one organellar RNase H1 (RNH1B or RNH1C) is required for embryonic development. The plastid-localized RNH1C affects plastid DNA copy number and sensitivity to replicative stress. Our results present the evolutionary history of RNH1 proteins in A. thaliana, demonstrate their canonical RNase H1 activity and indicate their role in early embryonic development.
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Affiliation(s)
- Jan Kuciński
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Sebastian Chamera
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Aleksandra Kmera
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - M Jordan Rowley
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sho Fujii
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Pragya Khurana
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Andrzej T Wierzbicki
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw, Poland
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