title: Mutations in MYB3R1 and MYB3R4 cause pleiotropic developmental defects and preferential down-regulation of multiple G2/M-specific genes in Arabidopsis.
abstract: R1R2R3-Myb proteins represent an evolutionarily conserved class of Myb family proteins important for cell cycle regulation and differentiation in eukaryotic cells. In plants, this class of Myb proteins are believed to regulate the transcription of G2/M phase-specific genes by binding to common cis-elements, called mitosis-specific activator (MSA) elements. In Arabidopsis (Arabidopsis thaliana), MYB3R1 and MYB3R4 act as transcriptional activators and positively regulate cytokinesis by activating the transcription of KNOLLE, which encodes a cytokinesis-specific syntaxin. Here, we show that the double mutation myb3r1 myb3r4 causes pleiotropic developmental defects, some of which are due to deficiency of KNOLLE whereas other are not, suggesting that multiple target genes are involved. Consistently, microarray analysis of the double mutant revealed altered expression of many genes, among which G2/M-specific genes showed significant overrepresentation of the MSA motif and a strong tendency to be down-regulated by the double mutation. Our results demonstrate, on a genome-wide level, the importance of the MYB3R-MSA pathway for regulating G2/M-specific transcription. In addition, MYB3R1 and MYB3R4 may have diverse roles during plant development by regulating G2/M-specific genes with various functions as well as genes possibly unrelated to the cell cycle.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Haga
authors.forename: Kosuke
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Takamasa
authors.initials: T
authors.lastname: Suzuki
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Maeo
authors.forename: Minoru
authors.initials: M
authors.lastname: Kubo
authors.forename: Misato
authors.initials: M
authors.lastname: Ohtani
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Mitsuda
authors.forename: Taku
authors.initials: T
authors.lastname: Demura
authors.forename: Kenzo
authors.initials: K
authors.lastname: Nakamura
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
authors.forename: Masaki
authors.initials: M
authors.lastname: Ito
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites; D002110:Caffeine / Q000494:pharmacology; D002455:Cell Division / Q000235:genetics*; D017124:Conserved Sequence; D004171:Diploidy; D015536:Down-Regulation; D016195:G2 Phase / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D050765:Qa-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics; D012639:Seeds; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C097724:KNOLLE protein, Arabidopsis; C520423:MYB3R1 protein, Arabidopsis; C520424:MYB3R4 protein, Arabidopsis; D050765:Qa-SNARE Proteins; D015534:Trans-Activators; D002110:Caffeine