Basic pentacysteine proteins mediate MADS domain complex binding to the DNA for tissue-specific expression of target genes in Arabidopsis.
Basic pentacysteine (BPC) transcription factors have been identified in a large variety of plant species. In Arabidopsis thaliana there are seven BPC genes, which, except for BPC5, are expressed ubiquitously. BPC genes are functionally redundant in a wide range of developmental processes. Recently, we reported that BPC1 binds to guanine and adenine (GA)-rich consensus sequences in the seedstick (STK) promoter in vitro and induces conformational changes. Here we show by chromatin immunoprecipitation experiments that in vivo BPCs also bind to the consensus boxes, and when these were mutated, expression from the STK promoter was derepressed, resulting in ectopic expression in the inflorescence. We also reveal that short vegetative phase (SVP) is a direct regulator of STK. SVP is a floral meristem identity gene belonging to the MADS box gene family. The SVP-APETALA1 (AP1) dimer recruits the SEUSS (SEU)-LEUNIG (LUG) transcriptional cosuppressor to repress floral homeotic gene expression in the floral meristem. Interestingly, we found that GA consensus sequences in the STK promoter to which BPCs bind are essential for recruitment of the corepressor complex to this promoter. Our data suggest that we have identified a new regulatory mechanism controlling plant gene expression that is probably generally used, when considering BPCs' wide expression profile and the frequent presence of consensus binding sites in plant promoters.
Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy.
Sara
S
Simonini
Irma
I
Roig-Villanova
Veronica
V
Gregis
Bilitis
B
Colombo
Lucia
L
Colombo
Martin M
MM
Kater
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001665:Binding Sites; D047369:Chromatin Immunoprecipitation; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005801:Genes, Homeobox; D026161:MADS Domain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018519:Meristem / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology
C091535:AP1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C417768:LUG protein, Arabidopsis; D026161:MADS Domain Proteins; C476012:SEEDSTICK protein, Arabidopsis; C407549:SVP protein, Arabidopsis; D014157:Transcription Factors