Survival of living organisms is fully dependent on their maintenance of genome integrity,being permanently threatened by replication stress in proliferating cells.Although the plant DNA damage response(DDR)regulator S...Survival of living organisms is fully dependent on their maintenance of genome integrity,being permanently threatened by replication stress in proliferating cells.Although the plant DNA damage response(DDR)regulator SOG1 has been demonstrated to cope with replication defects,accumulating evidence points to other pathways functioning independent of SOG1.Here,we report the roles of the Arabidopsis E2FA and EF2B transcription factors,two well-characterized regulators of DNA replication,in plant response to replication stress.Through a combination of reverse genetics and chromatin immunoprecipitation approaches,we show that E2FA and E2FB share many target genes with SOG1,providing evidence for their involvement in the DDR.Analysis of double-and triple-mutant combinations revealed that E2FB,rather than E2FA,plays the most prominent role in sustaining plant growth in the presence of replication defects,either operating antagonistically or synergistically with SOG1.Conversely,SOG1 aids in overcoming the replication defects of E2FA/E2FB-deficient plants.Collectively,our data reveal a complex transcriptional network controlling the replication stress response in which E2Fs and SOG1 act as key regulatory factors.展开更多
The effects of brassinosteroid signaling on shoot and root development have been characterized in great detail but a simple consistent positive or negative impact on a basic cellular parameter was not identified.In th...The effects of brassinosteroid signaling on shoot and root development have been characterized in great detail but a simple consistent positive or negative impact on a basic cellular parameter was not identified.In this study,we combined digital 3D single-cell shape analysis and single-cell mRNA sequencing to charac-terize root meristems and mature root segments of brassinosteroid-blind mutants and wild type.The resul-tant datasets demonstrate that brassinosteroid signaling affects neither cell volume nor cell proliferation capacity.Instead,brassinosteroid signaling is essential for the precise orientation of cell division planes and the extent and timing of anisotropic cell expansion.Moreover,we found that the cell-aligning effects of brassinosteroid signaling can propagate to normalize the anatomy of both adjacent and distant brassinosteroid-blind cells through non-cell-autonomous functions,which are sufficient to restore growth vigor.Finally,single-cell transcriptome data discern directly brassinosteroid-responsive genes from genes that can react non-cell-autonomously and highlight arabinogalactans as sentinels of brassinosteroid-dependent anisotropic cell expansion.展开更多
基金supported by grants from the Research Foundation Flanders(G011420N)Agence Nationale de la Recherche(21-CE20-0027).
文摘Survival of living organisms is fully dependent on their maintenance of genome integrity,being permanently threatened by replication stress in proliferating cells.Although the plant DNA damage response(DDR)regulator SOG1 has been demonstrated to cope with replication defects,accumulating evidence points to other pathways functioning independent of SOG1.Here,we report the roles of the Arabidopsis E2FA and EF2B transcription factors,two well-characterized regulators of DNA replication,in plant response to replication stress.Through a combination of reverse genetics and chromatin immunoprecipitation approaches,we show that E2FA and E2FB share many target genes with SOG1,providing evidence for their involvement in the DDR.Analysis of double-and triple-mutant combinations revealed that E2FB,rather than E2FA,plays the most prominent role in sustaining plant growth in the presence of replication defects,either operating antagonistically or synergistically with SOG1.Conversely,SOG1 aids in overcoming the replication defects of E2FA/E2FB-deficient plants.Collectively,our data reveal a complex transcriptional network controlling the replication stress response in which E2Fs and SOG1 act as key regulatory factors.
基金funded by core funding from the University of Lausanne,the Swiss National Science Foundation(grant 310030B_185379,awarded to C.S.H.)The Research Foundation-Flanders(FWO,post-doc fellowship 1215820N,awarded to T.E.)+2 种基金the European Research Council(ERC Start ing Grant TORPEDO,714055,awarded to B.D.R.)the BBSRC(grant BB/S002804/1 to G.W.B.)the Deutsche Forschungsgemeinschaft(DFG,post-doctoral fellowship GR 5009/1-1,awarded to M.G.).
文摘The effects of brassinosteroid signaling on shoot and root development have been characterized in great detail but a simple consistent positive or negative impact on a basic cellular parameter was not identified.In this study,we combined digital 3D single-cell shape analysis and single-cell mRNA sequencing to charac-terize root meristems and mature root segments of brassinosteroid-blind mutants and wild type.The resul-tant datasets demonstrate that brassinosteroid signaling affects neither cell volume nor cell proliferation capacity.Instead,brassinosteroid signaling is essential for the precise orientation of cell division planes and the extent and timing of anisotropic cell expansion.Moreover,we found that the cell-aligning effects of brassinosteroid signaling can propagate to normalize the anatomy of both adjacent and distant brassinosteroid-blind cells through non-cell-autonomous functions,which are sufficient to restore growth vigor.Finally,single-cell transcriptome data discern directly brassinosteroid-responsive genes from genes that can react non-cell-autonomously and highlight arabinogalactans as sentinels of brassinosteroid-dependent anisotropic cell expansion.
