Transcriptional program controlled by the floral homeotic gene AGAMOUS during early organogenesis.
Floral organs, whose identity is determined by specific combinations of homeotic genes, originate from a group of undifferentiated cells called the floral meristem. In Arabidopsis, the homeotic gene AGAMOUS (AG) terminates meristem activity and promotes development of stamens and carpels. To understand the program of gene expression activated by AG, we followed genome-wide expression during early stamen and carpel development. The AG target genes included most genes for which mutant screens revealed a function downstream of AG. Novel targets were validated by in situ hybridisation and binding to AG in vitro and in vivo. Transcription factors formed a large fraction of AG targets, suggesting that during early organogenesis, much of the genetic program is concerned with elaborating gene expression patterns. The results also suggest that AG and other homeotic proteins with which it interacts (SEPALLATA3, APETALA3, PISTILLATA) are coordinately regulated in a positive-feedback loop to maintain their own expression, and that AG activates biosynthesis of gibberellin, which has been proposed to promote the shift from meristem identity to differentiation.
Gómez-Mena
Concepción
C
Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK.
de Folter
Stefan
S
Costa
Maria Manuela R
MM
Angenent
Gerco C
GC
Sablowski
Robert
R
D026342:AGAMOUS Protein, Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D035264:Flowers / Q000254:growth & development / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005801:Genes, Homeobox / Q000235:genetics*; D018398:Homeodomain Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D026161:MADS Domain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010940:Plant Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic / Q000235:genetics*
D026342:AGAMOUS Protein, Arabidopsis; C091535:AP1 protein, Arabidopsis; C101342:APETALA 3 protein, Arabidopsis; D029681:Arabidopsis Proteins; C091536:CAL protein, Arabidopsis; D018398:Homeodomain Proteins; D026161:MADS Domain Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant