title: Partners in time: EARLY BIRD associates with ZEITLUPE and regulates the speed of the Arabidopsis clock.
abstract: The circadian clock of the model plant Arabidopsis (Arabidopsis thaliana) is made up of a complex series of interacting feedback loops whereby proteins regulate their own expression across day and night. early bird (ebi) is a circadian mutation that causes the clock to speed up: ebi plants have short circadian periods, early phase of clock gene expression, and are early flowering. We show that EBI associates with ZEITLUPE (ZTL), known to act in the plant clock as a posttranslational mediator of protein degradation. However, EBI is not degraded by its interaction with ZTL. Instead, ZTL counteracts the effect of EBI during the day and increases it at night, modulating the expression of key circadian components. The partnership of EBI with ZTL reveals a novel mechanism involved in controlling the complex transcription-translation feedback loops of the clock. This work highlights the importance of cross talk between the ubiquitination pathway and transcriptional control for regulation of the plant clock.
authors.affiliation: Department of Plant Physiology, Umea Plant Science Centre, Umea University, SE-901 87 Umea, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Johansson
authors.forename: Harriet G
authors.initials: HG
authors.lastname: McWatters
authors.forename: László
authors.initials: L
authors.lastname: Bakó
authors.forename: Naoki
authors.initials: N
authors.lastname: Takata
authors.forename: Péter
authors.initials: P
authors.lastname: Gyula
authors.forename: Anthony
authors.initials: A
authors.lastname: Hall
authors.forename: David E
authors.initials: DE
authors.lastname: Somers
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Millar
authors.forename: Maria E
authors.initials: ME
authors.lastname: Eriksson
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D057906:Circadian Clocks / Q000235:genetics*; D002940:Circadian Rhythm; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018749:RNA, Plant / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D018749:RNA, Plant; D014157:Transcription Factors; C410503:ZTL protein, Arabidopsis