The transcription factor CONSTANS(CO)integrates day-length information to induce the expression of florigen FLOWERING LOCUS T(FT)in Arabidopsis.We recently reported that the C-terminal CCT domain of CO forms a complex...The transcription factor CONSTANS(CO)integrates day-length information to induce the expression of florigen FLOWERING LOCUS T(FT)in Arabidopsis.We recently reported that the C-terminal CCT domain of CO forms a complex with NUCLEAR FACTOR-YB/YC to recognize multiple cis-elements in the FT promoter,and the N-terminal tandem B-box domains form a homomultimeric assembly.However,the mechanism and biological function of CO multimerization remained unclear.Here,we report that CO takes on a head-to-tail oligomeric configuration via its B-boxes to mediate FT activation in long days.The crystal structure of B-boxesCOreveals a closely connected tandem B-box fold forming a continuous head-to-tail assembly through unique CDHH zinc fingers.Mutating the key residues involved in CO oligomerization resulted in a non-functional CO,as evidenced by the inability to rescue co mutants.By contrast,a transgene encoding a human p53-derived tetrameric peptide in place of the B-boxesCOrescued co mutant,emphasizing the essential role of BboxesCO-mediated oligomerization.Furthermore,we found that the four TGTG-bearing cis-elements in FT proximal promoter are required for FT activation in long days.Our results suggest that CO forms a multimer to bind to the four TGTG motifs in the FT promoter to mediate FT activation.展开更多
基金supported by the Shenzhen Science and Technology Program(JCYJ20200109110403829 and KQTD20190929173906742 to Jiamu Du)the National Natural Science Foundation of China(31721001 to Yuehui He)+1 种基金the National Key Research and Development Program of China(2017YFA0503803 to Yuehui He)the Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes(2019KSYS006 to Jiamu Du)。
文摘The transcription factor CONSTANS(CO)integrates day-length information to induce the expression of florigen FLOWERING LOCUS T(FT)in Arabidopsis.We recently reported that the C-terminal CCT domain of CO forms a complex with NUCLEAR FACTOR-YB/YC to recognize multiple cis-elements in the FT promoter,and the N-terminal tandem B-box domains form a homomultimeric assembly.However,the mechanism and biological function of CO multimerization remained unclear.Here,we report that CO takes on a head-to-tail oligomeric configuration via its B-boxes to mediate FT activation in long days.The crystal structure of B-boxesCOreveals a closely connected tandem B-box fold forming a continuous head-to-tail assembly through unique CDHH zinc fingers.Mutating the key residues involved in CO oligomerization resulted in a non-functional CO,as evidenced by the inability to rescue co mutants.By contrast,a transgene encoding a human p53-derived tetrameric peptide in place of the B-boxesCOrescued co mutant,emphasizing the essential role of BboxesCO-mediated oligomerization.Furthermore,we found that the four TGTG-bearing cis-elements in FT proximal promoter are required for FT activation in long days.Our results suggest that CO forms a multimer to bind to the four TGTG motifs in the FT promoter to mediate FT activation.
