title: ABAP1 is a novel plant Armadillo BTB protein involved in DNA replication and transcription.
abstract: In multicellular organisms, organogenesis requires a tight control of the balance between cell division and cell differentiation. Distinct signalling pathways that connect both cellular processes with developmental cues might have evolved to suit different developmental plans. Here, we identified and characterized a novel protein that interacts with pre-replication complex (pre-RC) subunits, designated Armadillo BTB Arabidopsis protein 1 (ABAP1). Overexpression of ABAP1 in plants limited mitotic DNA replication and decreased cell proliferation in leaves, whereas ABAP1 downregulation increased cell division rates. Activity of ABAP1 in transcription was supported by its association with the transcription factor AtTCP24. The ABAP1-AtTCP24 complex bound specifically to the promoters of AtCDT1a and AtCDT1b in vitro and in vivo. Moreover, expression levels of AtCDT1a and AtCDT1b were reduced in ABAP1-overexpressing plants and they were increased in plants with reduced levels of ABAP1. We propose that ABAP1 participates in a negative feedback loop regulating mitotic DNA replication during leaf development, either by repressing transcription of pre-RC genes and possibly by regulating pre-RC utilization through direct association with pre-RC components.
authors.affiliation: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Hana Paula
authors.initials: HP
authors.lastname: Masuda
authors.forename: Luiz Mors
authors.initials: LM
authors.lastname: Cabral
authors.forename: Lieven
authors.initials: L
authors.lastname: De Veylder
authors.forename: Milos
authors.initials: M
authors.lastname: Tanurdzic
authors.forename: Janice
authors.initials: J
authors.lastname: de Almeida Engler
authors.forename: Danny
authors.initials: D
authors.lastname: Geelen
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
authors.forename: Robert A
authors.initials: RA
authors.lastname: Martienssen
authors.forename: Paulo C G
authors.initials: PC
authors.lastname: Ferreira
authors.forename: Adriana S
authors.initials: AS
authors.lastname: Hemerly
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051186:Armadillo Domain Proteins / Q000378:metabolism; D002455:Cell Division; D049109:Cell Proliferation; D004247:DNA / Q000378:metabolism; D004261:DNA Replication; D015536:Down-Regulation; D017343:Genes, Plant; D008938:Mitosis; D008954:Models, Biological; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D011485:Protein Binding; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D051186:Armadillo Domain Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; D004247:DNA