title: DOF AFFECTING GERMINATION 2 is a positive regulator of light-mediated seed germination and is repressed by DOF AFFECTING GERMINATION 1.
abstract: BACKGROUND
  The transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a repressor of the light-mediated seed germination process. DAG1 acts downstream PHYTOCHROME INTERACTING FACTOR3-LIKE 5 (PIL5), the master repressor, and negatively regulates gibberellin biosynthesis by directly repressing the biosynthetic gene AtGA3ox1. The Dof protein DOF AFFECTING GERMINATION (DAG2) shares a high degree of aminoacidic identity with DAG1. While DAG1 inactivation considerably increases the germination capability of seeds, the dag2 mutant has seeds with a germination potential substantially lower than the wild-type, indicating that these factors may play opposite roles in seed germination.
  
  
  RESULTS
  We show here that DAG2 expression is positively regulated by environmental factors triggering germination, whereas its expression is repressed by PIL5 and DAG1; by Chromatin Immuno Precipitation (ChIP) analysis we prove that DAG1 directly regulates DAG2. In addition, we show that Red light significantly reduces germination of dag2 mutant seeds.
  
  
  CONCLUSIONS
  In agreement with the seed germination phenotype of the dag2 mutant previously published, the present data prove that DAG2 is a positive regulator of the light-mediated seed germination process, and particularly reveal that this protein plays its main role downstream of PIL5 and DAG1 in the phytochrome B (phyB)-mediated pathway.
authors: Silvia
authors: S
authors: Santopolo
authors: Alessandra
authors: A
authors: Boccaccini
authors: Riccardo
authors: R
authors: Lorrai
authors: Veronica
authors: V
authors: Ruta
authors: Davide
authors: D
authors: Capauto
authors: Emanuele
authors: E
authors: Minutello
authors: Giovanna
authors: G
authors: Serino
authors: Paolo
authors: P
authors: Costantino
authors: Paola
authors: P
authors: Vittorioso
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000196:embryology* / Q000235:genetics / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003624:Darkness; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D017343:Genes, Plant; D018525:Germination / Q000235:genetics / Q000528:radiation effects*; D005875:Gibberellins / Q000378:metabolism / Q000494:pharmacology; D008027:Light; D009154:Mutation / Q000235:genetics; D051939:Phytochrome B / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D012639:Seeds / Q000196:embryology* / Q000528:radiation effects; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D005875:Gibberellins; D051939:Phytochrome B; D012097:Repressor Proteins; D014157:Transcription Factors; C407526:DAG1 protein, Arabidopsis; C000604033:DAG2 protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; C508068:At2g20180 protein, Arabidopsis