title: TONSOKU is expressed in S phase of the cell cycle and its defect delays cell cycle progression in Arabidopsis.
abstract: TONSOKU(TSK)/MGOUN3/BRUSHY1 of Arabidopsis thaliana encodes a nuclear leucine-glycine-aspargine (LGN) domain protein implicated to be involved in genome maintenance, and mutants with defects in TSK show a fasciated stem with disorganized meristem structures. We identified a homolog of TSK from tobacco BY-2 cells (NtTSK), which showed high sequence conservation both in the LGN domain and in leucine-rich repeats with AtTSK. The NtTSK gene was expressed during S phase of the cell cycle in tobacco BY-2 cells highly synchronized for cell division. The tsk mutants of Arabidopsis contained an increased proportion of cells with 4C nuclei and cells expressing cyclin B1 compared with the wild type. These results suggest that TSK is required during the cell cycle and defects of TSK cause the arrest of cell cycle progression at G2/M phase.
authors.affiliation: Laboratory of Biochemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan. takamasa@thaliana.myhome.cx
authors.forename: Takamasa
authors.initials: T
authors.lastname: Suzuki
authors.forename: Sakiko
authors.initials: S
authors.lastname: Nakajima
authors.forename: Soichi
authors.initials: S
authors.lastname: Inagaki
authors.forename: Makiko
authors.initials: M
authors.lastname: Hirano-Nakakita
authors.forename: Ken
authors.initials: K
authors.lastname: Matsuoka
authors.forename: Taku
authors.initials: T
authors.lastname: Demura
authors.forename: Hiroo
authors.initials: H
authors.lastname: Fukuda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Morikami
authors.forename: Kenzo
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D019926:Cyclin B / Q000235:genetics / Q000378:metabolism; D016195:G2 Phase / Q000235:genetics; D018816:Genes, cdc / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D019926:Cyclin B; D010940:Plant Proteins; C462528:CycB1 protein, Arabidopsis; C487787:AT3G18730 protein, Arabidopsis; D002868:Chromosomal Proteins, Non-Histone