ABAP1 is a novel plant Armadillo BTB protein involved in DNA replication and transcription.
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.
Masuda
Hana Paula
HP
Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Cabral
Luiz Mors
LM
De Veylder
Lieven
L
Tanurdzic
Milos
M
de Almeida Engler
Janice
J
Geelen
Danny
D
Inzé
Dirk
D
Martienssen
Robert A
RA
Ferreira
Paulo C G
PC
Hemerly
Adriana S
AS
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
D029681:Arabidopsis Proteins; D051186:Armadillo Domain Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; D004247:DNA