title: The FRIGIDA complex activates transcription of FLC, a strong flowering repressor in Arabidopsis, by recruiting chromatin modification factors.
abstract: The flowering of Arabidopsis thaliana winter annuals is delayed until the subsequent spring by the strong floral repressor FLOWERING LOCUS C (FLC). FRIGIDA (FRI) activates the transcription of FLC, but the molecular mechanism remains elusive. The fri mutation causes early flowering with reduced FLC expression similar to frl1, fes1, suf4, and flx, which are mutants of FLC-specific regulators. Here, we report that FRI acts as a scaffold protein interacting with FRL1, FES1, SUF4, and FLX to form a transcription activator complex (FRI-C). Each component of FRI-C has a specialized function. SUF4 binds to a cis-element of the FLC promoter, FLX and FES1 have transcriptional activation potential, and FRL1 and FES1 stabilize the complex. FRI-C recruits a general transcription factor, a TAF14 homolog, and chromatin modification factors, the SWR1 complex and SET2 homolog. Complex formation was confirmed by the immunoprecipitation of FRI-associated proteins followed by mass spectrometric analysis. Our results provide insight into how a specific transcription activator recruits chromatin modifiers to regulate a key flowering gene.
authors.affiliation: National Research Laboratory of Plant Developmental Genetics, School of Biological Sciences, Seoul National University, Seoul, 151-742, Korea.
authors.forename: Kyuha
authors.initials: K
authors.lastname: Choi
authors.forename: Juhyun
authors.initials: J
authors.lastname: Kim
authors.forename: Hyun-Ju
authors.initials: HJ
authors.lastname: Hwang
authors.forename: Sanghee
authors.initials: S
authors.lastname: Kim
authors.forename: Chulmin
authors.initials: C
authors.lastname: Park
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Kim
authors.forename: Ilha
authors.initials: I
authors.lastname: Lee
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010802:Phylogeny; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; D002843:Chromatin; C418902:At5g10140 protein, Arabidopsis; C414613:FRI protein, Arabidopsis; D026161:MADS Domain Proteins