Repression of flowering by the miR172 target SMZ.
A small mobile protein, encoded by the FLOWERING LOCUS T (FT) locus, plays a central role in the control of flowering. FT is regulated positively by CONSTANS (CO), the output of the photoperiod pathway, and negatively by FLC, which integrates the effects of prolonged cold exposure. Here, we reveal the mechanisms of regulation by the microRNA miR172 target SCHLAFMUTZE (SMZ), a potent repressor of flowering. Whole-genome mapping of SMZ binding sites demonstrates not only direct regulation of FT, but also of many other flowering time regulators acting both upstream and downstream of FT, indicating an important role of miR172 and its targets in fine tuning the flowering response. A role for the miR172/SMZ module as a rheostat in flowering time is further supported by SMZ binding to several other genes encoding miR172 targets. Finally, we show that the action of SMZ is completely dependent on another floral repressor, FLM, providing the first direct connection between two important classes of flowering time regulators, AP2- and MADS-domain proteins.
Mathieu
Johannes
J
Max Planck Institute for Developmental Biology, Department of Molecular Biology, Tübingen, Germany.
Yant
Levi J
LJ
Mürdter
Felix
F
Küttner
Frank
F
Schmid
Markus
M
D016960:Agrobacterium tumefaciens; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000378:metabolism*; D035264:Flowers / Q000235:genetics* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D026161:MADS Domain Proteins / Q000502:physiology; D018519:Meristem / Q000502:physiology; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D050505:Mutant Proteins / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D017440:Photoperiod; D018515:Plant Leaves / Q000502:physiology; D030821:Plants, Genetically Modified; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000502:physiology; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014170:Transformation, Genetic
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C418902:At5g10140 protein, Arabidopsis; C522476:FLM protein, Arabidopsis; C418905:FT protein, Arabidopsis; D026161:MADS Domain Proteins; D035683:MicroRNAs; C543702:Mirn172 microRNA, Arabidopsis; D050505:Mutant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C544159:SMZ protein, Arabidopsis; C544160:SNZ protein, Arabidopsis; D014157:Transcription Factors