title: The Arabidopsis BET bromodomain factor GTE4 is involved in maintenance of the mitotic cell cycle during plant development.
abstract: Bromodomain and Extra Terminal domain (BET) proteins are characterized by the presence of two types of domains, the bromodomain and the extra terminal domain. They bind to acetylated lysines present on histone tails and control gene transcription. They are also well known to play an important role in cell cycle regulation. In Arabidopsis (Arabidopsis thaliana), there are 12 BET genes; however, only two of them, IMBIBITION INDUCIBLE1 and GENERAL TRANSCRIPTION FACTOR GROUP E6 (GTE6), were functionally analyzed. We characterized GTE4 and show that gte4 mutant plants have some characteristic features of cell cycle mutants. Their size is reduced, and they have jagged leaves and a reduced number of cells in most organs. Moreover, cell size is considerably increased in the root, and, interestingly, the root quiescent center identity seems to be partially lost. Cell cycle analyses revealed that there is a delay in activation of the cell cycle during germination and a premature arrest of cell proliferation, with a switch from mitosis to endocycling, leading to a statistically significant increase in ploidy levels in the differentiated organs of gte4 plants. Our results point to a role of GTE4 in cell cycle regulation and specifically in the maintenance of the mitotic cell cycle.
authors.affiliation: Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, 20133 Milan, Italy.
authors.forename: Chiara A
authors.initials: CA
authors.lastname: Airoldi
authors.forename: Federica Della
authors.initials: FD
authors.lastname: Rovere
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Falasca
authors.forename: Giada
authors.initials: G
authors.lastname: Marino
authors.forename: Maarten
authors.initials: M
authors.lastname: Kooiker
authors.forename: Maria Maddalena
authors.initials: MM
authors.lastname: Altamura
authors.forename: Sandra
authors.initials: S
authors.lastname: Citterio
authors.forename: Martin M
authors.initials: MM
authors.lastname: Kater
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D048429:Cell Size; D004269:DNA, Bacterial / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D018525:Germination; D008938:Mitosis; D016254:Mutagenesis, Insertional; D009154:Mutation; D010802:Phylogeny; D018517:Plant Roots / Q000166:cytology; D018749:RNA, Plant / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D018749:RNA, Plant; C036483:T-DNA; D014157:Transcription Factors