The circadian clock entrained by environmental light-dark cycles enables plants to fine-tune diurnal growth and developmental responses.Here,we show that physical interactions among evening clock components,including ...The circadian clock entrained by environmental light-dark cycles enables plants to fine-tune diurnal growth and developmental responses.Here,we show that physical interactions among evening clock components,including PSEUDO-RESPONSE REGULATOR 5(PRR5),TIMING OF CAB EXPRESSION 1(TOC1),and the Evening Complex(EC)component EARLY FLOWERING 3(ELF3),define a diurnal repressive chromatin structure specifically at the PHYTOCHROME-INTERACTING FACTOR 4(PIF4)locus in Arabidopsis.These three clock components act interdependently as well as independently to repress nighttime hypocotyl elongation,as hypocotyl elongation rate dramatically increased specifically at nighttime in the prr5-1 toc1-21 elf3-1 mutant,concomitantly with a substantial increase in PIF4 expression.Transcriptional repression of PIF4 by ELF3,PRR5,and TOC1 is mediated by the SWI2/SNF2-RELATED(SWR1)chromatin remodeling complex,which incorporates histone H2A.Z at thePIF4 locus,facilitating robust epigenetic suppression ofPIF4 during the evening.Overall,these findings demonstrate that the PRR-EC-SWR1 complex represses hypocotyl elongation at night through a distinctive chromatin domain covering PIF4 chromatin.展开更多
Deposition of the H2A.Z histone variant by the SWR1 complex （SWRI-C） in regulatory regions of specific loci modulates transcription. Characterization of mutations in Arabidopsis thaliana homologs of yeast SWRI-C has...Deposition of the H2A.Z histone variant by the SWR1 complex （SWRI-C） in regulatory regions of specific loci modulates transcription. Characterization of mutations in Arabidopsis thaliana homologs of yeast SWRI-C has revealed a role for H2A.Z exchange in a variety of developmental processes. Nevertheless, the exact composition of plant SWRI-C and how it is recruited to target genes remains to be established. Here we show that SWC4, the Arabidopsis homolog of yeast SANT domain protein Swc4/Eaf2, is a DNA-binding protein that interacts with SWR1-C subunits. We demonstrate that the swc4-1 knockout mutant is embryo- lethal, while SWC4 RNAi knockdown lines display pleiotropic phenotypic alterations in vegetative and repro- ductive traits, including acceleration of flowering time, indicating that SWC4 controls post-embryonic processes. Transcriptomic analyses and genome-wide profiling of H2A.Z indicate that SWC4 represses tran- scription of a number of genes, including the floral integrator FT and key transcription factors, mainly by modulating H2A.Z deposition. Interestingly, SWC4 silencing does not affect H2A.Z deposition at the FLC locus nor expression of this gene, a master regulator of flowering previously shown to be controlled by SWR1-C. Importantly, we find that SWC4 recognizes specific AT-rich DNA elements in the chromatin regions of target genes and that SWC4 silencing impairs SWRI-C binding at FT. Collectively, our data suggest that SWC4 regulates plant growth and development by aiding SWR1-C recruitment and modulating H2A.Z deposition.展开更多
Incorporation of the histone variant H2A.Z into nucleosomes by the SWR1 chromatin remodeling complex is a critical step in eukaryotic gene regulation. In Arabidopsis, SWRlc and H2A.Z have been shown to con- trol gene ...Incorporation of the histone variant H2A.Z into nucleosomes by the SWR1 chromatin remodeling complex is a critical step in eukaryotic gene regulation. In Arabidopsis, SWRlc and H2A.Z have been shown to con- trol gene expression underlying development and environmental responses. Although they have been implicated in defense, the specific roles of the complex subunits and H2A.Z in immunity are not well under- stood. In this study, we analyzed the roles of the SWRlc subunits, PHOTOPERIOD-INDEPENDENT EARLY FLOWERING1 （PIE1）, ACTIN-RELATED PROTEIN6 （ARP6）, and SWR1 COMPLEX 6 （SWC6）, as well as H2A.Z, in defense and gene regulation. We found that SWRlc components play different roles in resistance to different pathogens. Loss of PIE1 and SWC6 function as well as depletion of H2A.Z led to reduced basal resistance, while loss of ARP6 fucntion resulted in enhanced resistance. We found that mutations in PIE1 and SWC6 resulted in impaired effector-triggered immunity. Mutation in SWRlc components and H2A.Z also resulted in compromised jasmonic acid/ethylene-mediated immunity. Genome-wide expres- sion analyses similarly reveal distinct roles for H2A.Z and SWRlc components in gene regulation, and sug- gest a potential role for PIE1 in the regulation of the cross talk between defense signaling pathways. Our data show that although they are part of the same complex, Arabidopsis SWRlc components could have non-redundant functions in plant immunity and gene regulation.展开更多
Chromatin remodeling complexes serve as crucial regulators of chromatin structure in eukaryotes,govern-ing the transcription,DNA repair,and genome stability.Compared with chromatin remodelers in yeast and animals,plan...Chromatin remodeling complexes serve as crucial regulators of chromatin structure in eukaryotes,govern-ing the transcription,DNA repair,and genome stability.Compared with chromatin remodelers in yeast and animals,plant chromatin remodelers exhibit both conserved and lineage-specific features,which facilitate unique adaptive responses.Cutting-edge approaches in biochemistry,epigenomics,and proteomics are revealing unprecedented insights into plant chromatin remodeling mechanisms,and genetic studies continue to demonstrate their essential roles in maintaining chromatin state homeostasis during plant growth and stress adaptation.This review synthesizes current understanding of plant chromatin remodel-ing complexes,with particular focuses on their specialized subunit compositions,mechanistic diversity,and integrative roles in epigenetic regulation.Furthermore,we highlight how these complexes interact with histone modifications,DNA methylation pathways,and transcription factor networks to orchestrate plantdevelopmentandstress responses.展开更多
Adenosine triphosphate-dependent chromatin remodeling complexes are important for the regulation of transcription,DNA replication,and genome stability in eukaryotes.Although genetic studies have illustrated various bi...Adenosine triphosphate-dependent chromatin remodeling complexes are important for the regulation of transcription,DNA replication,and genome stability in eukaryotes.Although genetic studies have illustrated various biological functions of core and accessory subunits of chromatin-remodeling complexes in plants,the identification and characterization of chromatin-remodeling complexes in plants is lagging behind that in yeast and animals.Recent studies determined whether and how the Arabidopsis SWI/SNF,ISWI,INO80,SWR1,and CHD chromatin remodelers function in multi-subunit complexes in Arabidopsis.Both conserved and plant-specific subunits of chromatin-remodeling complexes have been identified and characterized.These findings provide a basis for further studies of the molecular mechanisms by which the chromatinremodeling complexes function in plants.展开更多
基金supported by the Basic Science Research(NRF2022R1A2B5B02001266 to P.J.S.and NRF-2023R1A2C3002386 to E.O.)Basic Research Laboratory(NRF-2022R1A4A3024451)programs provided by the National Research Foundation of Korea.
文摘The circadian clock entrained by environmental light-dark cycles enables plants to fine-tune diurnal growth and developmental responses.Here,we show that physical interactions among evening clock components,including PSEUDO-RESPONSE REGULATOR 5(PRR5),TIMING OF CAB EXPRESSION 1(TOC1),and the Evening Complex(EC)component EARLY FLOWERING 3(ELF3),define a diurnal repressive chromatin structure specifically at the PHYTOCHROME-INTERACTING FACTOR 4(PIF4)locus in Arabidopsis.These three clock components act interdependently as well as independently to repress nighttime hypocotyl elongation,as hypocotyl elongation rate dramatically increased specifically at nighttime in the prr5-1 toc1-21 elf3-1 mutant,concomitantly with a substantial increase in PIF4 expression.Transcriptional repression of PIF4 by ELF3,PRR5,and TOC1 is mediated by the SWI2/SNF2-RELATED(SWR1)chromatin remodeling complex,which incorporates histone H2A.Z at thePIF4 locus,facilitating robust epigenetic suppression ofPIF4 during the evening.Overall,these findings demonstrate that the PRR-EC-SWR1 complex represses hypocotyl elongation at night through a distinctive chromatin domain covering PIF4 chromatin.
文摘Deposition of the H2A.Z histone variant by the SWR1 complex （SWRI-C） in regulatory regions of specific loci modulates transcription. Characterization of mutations in Arabidopsis thaliana homologs of yeast SWRI-C has revealed a role for H2A.Z exchange in a variety of developmental processes. Nevertheless, the exact composition of plant SWRI-C and how it is recruited to target genes remains to be established. Here we show that SWC4, the Arabidopsis homolog of yeast SANT domain protein Swc4/Eaf2, is a DNA-binding protein that interacts with SWR1-C subunits. We demonstrate that the swc4-1 knockout mutant is embryo- lethal, while SWC4 RNAi knockdown lines display pleiotropic phenotypic alterations in vegetative and repro- ductive traits, including acceleration of flowering time, indicating that SWC4 controls post-embryonic processes. Transcriptomic analyses and genome-wide profiling of H2A.Z indicate that SWC4 represses tran- scription of a number of genes, including the floral integrator FT and key transcription factors, mainly by modulating H2A.Z deposition. Interestingly, SWC4 silencing does not affect H2A.Z deposition at the FLC locus nor expression of this gene, a master regulator of flowering previously shown to be controlled by SWR1-C. Importantly, we find that SWC4 recognizes specific AT-rich DNA elements in the chromatin regions of target genes and that SWC4 silencing impairs SWRI-C binding at FT. Collectively, our data suggest that SWC4 regulates plant growth and development by aiding SWR1-C recruitment and modulating H2A.Z deposition.
文摘Incorporation of the histone variant H2A.Z into nucleosomes by the SWR1 chromatin remodeling complex is a critical step in eukaryotic gene regulation. In Arabidopsis, SWRlc and H2A.Z have been shown to con- trol gene expression underlying development and environmental responses. Although they have been implicated in defense, the specific roles of the complex subunits and H2A.Z in immunity are not well under- stood. In this study, we analyzed the roles of the SWRlc subunits, PHOTOPERIOD-INDEPENDENT EARLY FLOWERING1 （PIE1）, ACTIN-RELATED PROTEIN6 （ARP6）, and SWR1 COMPLEX 6 （SWC6）, as well as H2A.Z, in defense and gene regulation. We found that SWRlc components play different roles in resistance to different pathogens. Loss of PIE1 and SWC6 function as well as depletion of H2A.Z led to reduced basal resistance, while loss of ARP6 fucntion resulted in enhanced resistance. We found that mutations in PIE1 and SWC6 resulted in impaired effector-triggered immunity. Mutation in SWRlc components and H2A.Z also resulted in compromised jasmonic acid/ethylene-mediated immunity. Genome-wide expres- sion analyses similarly reveal distinct roles for H2A.Z and SWRlc components in gene regulation, and sug- gest a potential role for PIE1 in the regulation of the cross talk between defense signaling pathways. Our data show that although they are part of the same complex, Arabidopsis SWRlc components could have non-redundant functions in plant immunity and gene regulation.
基金the National Key Research and Development Program of China(2024YFD1200800)the National Natural Science Foundation of China(32470346).
文摘Chromatin remodeling complexes serve as crucial regulators of chromatin structure in eukaryotes,govern-ing the transcription,DNA repair,and genome stability.Compared with chromatin remodelers in yeast and animals,plant chromatin remodelers exhibit both conserved and lineage-specific features,which facilitate unique adaptive responses.Cutting-edge approaches in biochemistry,epigenomics,and proteomics are revealing unprecedented insights into plant chromatin remodeling mechanisms,and genetic studies continue to demonstrate their essential roles in maintaining chromatin state homeostasis during plant growth and stress adaptation.This review synthesizes current understanding of plant chromatin remodel-ing complexes,with particular focuses on their specialized subunit compositions,mechanistic diversity,and integrative roles in epigenetic regulation.Furthermore,we highlight how these complexes interact with histone modifications,DNA methylation pathways,and transcription factor networks to orchestrate plantdevelopmentandstress responses.
基金supported by the National Natural Science Foundation of China(32025003)the National Key Research and Development Program of China(2016YFA0500801)from the Chinese Ministry of Science and Technology。
文摘Adenosine triphosphate-dependent chromatin remodeling complexes are important for the regulation of transcription,DNA replication,and genome stability in eukaryotes.Although genetic studies have illustrated various biological functions of core and accessory subunits of chromatin-remodeling complexes in plants,the identification and characterization of chromatin-remodeling complexes in plants is lagging behind that in yeast and animals.Recent studies determined whether and how the Arabidopsis SWI/SNF,ISWI,INO80,SWR1,and CHD chromatin remodelers function in multi-subunit complexes in Arabidopsis.Both conserved and plant-specific subunits of chromatin-remodeling complexes have been identified and characterized.These findings provide a basis for further studies of the molecular mechanisms by which the chromatinremodeling complexes function in plants.
