title: CRYPTIC PRECOCIOUS/MED12 is a novel flowering regulator with multiple target steps in Arabidopsis.
abstract: The proper timing of flowering is of crucial importance for reproductive success of plants. Regulation of flowering is orchestrated by inputs from both environmental and endogenous signals such as daylength, light quality, temperature and hormones, and key flowering regulators construct several parallel and interactive genetic pathways. This integrative regulatory network has been proposed to create robustness as well as plasticity of the regulation. Although knowledge of key genes and their regulation has been accumulated, there still remains much to learn about how they are organized into an integrative regulatory network. Here, we have analyzed the CRYPTIC PRECOCIOUS (CRP) gene for the Arabidopsis counterpart of the MED12 subunit of the Mediator. A novel dominant mutant, crp-1D, which causes up-regulation of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), FRUITFULL (FUL) and APETALA1 (AP1) expression in a FLOWERING LOCUS T (FT)-dependent manner, was identified in an enhancer screen of the early-flowering phenotype of 35S::FT. Genetic and molecular analysis of both crp-1D and crp loss-of-function alleles showed that MED12/CRP is required not only for proper regulation of SOC1, FUL and AP1, but also for up-regulation of FT, TWIN SISTER OF FT (TSF) and FD, and down-regulation of FLOWERING LOCUS C (FLC). These observations suggest that MED12/CRP is a novel flowering regulator with multiple regulatory target steps both upstream and downstream of the key flowering regulators including FT florigen. Our work, taken together with recent studies of other Mediator subunit genes, supports an emerging view that the Mediator plays multiple roles in the regulation of flowering.
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501 Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Imura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Sumiko
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Masahiko
authors.initials: M
authors.lastname: Furutani
authors.forename: Masao
authors.initials: M
authors.lastname: Tasaka
authors.forename: Mitsutomo
authors.initials: M
authors.lastname: Abe
authors.forename: Takashi
authors.initials: T
authors.lastname: Araki
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000378:metabolism; D009154:Mutation; D049488:Phosphatidylethanolamine Binding Protein / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C546592:CENTRAL CITY protein, Arabidopsis; C418902:At5g10140 protein, Arabidopsis; C418905:FT protein, Arabidopsis; C546591:GRAND CENTRAL protein, Arabidopsis; D026161:MADS Domain Proteins; D049488:Phosphatidylethanolamine Binding Protein; D012097:Repressor Proteins; C500577:TSF protein, Arabidopsis