DNA Topoisomerase Iα Affects the Floral Transition.
DNA topoisomerases modulate DNA topology to maintain chromosome superstructure and genome integrity, which is indispensable for DNA replication and RNA transcription. Their function in plant development still remains largely unknown. Here, we report a hitherto unidentified role of Topoisomerase Iα (TOP1α) in controlling flowering time in Arabidopsis (Arabidopsis thaliana). Loss of function of TOP1α results in early flowering under both long and short days. This is attributed mainly to a decrease in the expression of a central flowering repressor, FLOWERING LOCUS C (FLC), and its close homologs, MADS AFFECTING FLOWERING4 (MAF4) and MAF5, during the floral transition. TOP1α physically binds to the genomic regions of FLC, MAF4, and MAF5 and promotes the association of RNA polymerase II complexes to their transcriptional start sites. These correlate with the changes in histone modifications but do not directly affect nucleosome occupancy at these loci. Our results suggest that TOP1α mediates DNA topology to facilitate the recruitment of RNA polymerase II at FLC, MAF4, and MAF5 in conjunction with histone modifications, thus facilitating the expression of these key flowering repressors to prevent precocious flowering in Arabidopsis.
Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543, Singapore (X.G., L.S., Y.Z.P., H.Y.); and.|Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China (Y.G.).
Ximing
X
Gong
Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543, Singapore (X.G., L.S., Y.Z.P., H.Y.); and.|Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China (Y.G.).
Lisha
L
Shen
Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543, Singapore (X.G., L.S., Y.Z.P., H.Y.); and.|Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China (Y.G.).
Ya Zhi
YZ
Peng
Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543, Singapore (X.G., L.S., Y.Z.P., H.Y.); and.|Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China (Y.G.).
Yinbo
Y
Gan
Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, 117543, Singapore (X.G., L.S., Y.Z.P., H.Y.); and dbsyuhao@nus.edu.sg.|Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China (Y.G.) dbsyuhao@nus.edu.sg.
Hao
0000-0002-9778-8855
H
Yu
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004264:DNA Topoisomerases, Type I / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D006657:Histones / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism; D030821:Plants, Genetically Modified; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; C418902:At5g10140 protein, Arabidopsis; D006657:Histones; D026161:MADS Domain Proteins; C585560:MAF4 protein, Arabidopsis; C553101:MAF5 protein, Arabidopsis; D009707:Nucleosomes; D012097:Repressor Proteins; D012319:RNA Polymerase II; D004264:DNA Topoisomerases, Type I; C469258:TOP1alpha protein, Arabidopsis