title: Physcomitrella cyclin-dependent kinase A links cell cycle reactivation to other cellular changes during reprogramming of leaf cells.
abstract: During regeneration, differentiated plant cells can be reprogrammed to produce stem cells, a process that requires coordination of cell cycle reactivation with acquisition of other cellular characteristics. However, the factors that coordinate the two functions during reprogramming have not been determined. Here, we report a link between cell cycle reactivation and the acquisition of new cell-type characteristics through the activity of cyclin-dependent kinase A (CDKA) during reprogramming in the moss Physcomitrella patens. Excised gametophore leaf cells of P. patens are readily reprogrammed, initiate tip growth, and form chloronema apical cells with stem cell characteristics at their first cell division. We found that leaf cells facing the cut undergo CDK activation along with induction of a D-type cyclin, tip growth, and transcriptional activation of protonema-specific genes. A DNA synthesis inhibitor, aphidicolin, inhibited cell cycle progression but prevented neither tip growth nor protonemal gene expression, indicating that cell cycle progression is not required for acquisition of protonema cell-type characteristics. By contrast, treatment with a CDK inhibitor or induction of dominant-negative CDKA;1 protein inhibited not only cell cycle progression but also tip growth and protonemal gene expression. These findings indicate that cell cycle progression is coordinated with other cellular changes by the concomitant regulation through CDKA;1.
authors.affiliation: Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Okazaki 444-8585, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Murata
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Sato
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Nishiyama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hiwatashi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Imai
authors.forename: Mina
authors.initials: M
authors.lastname: Kimura
authors.forename: Nagisa
authors.initials: N
authors.lastname: Sugimoto
authors.forename: Asaka
authors.initials: A
authors.lastname: Akita
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Oguri
authors.forename: William E
authors.initials: WE
authors.lastname: Friedman
authors.forename: Mitsuyasu
authors.initials: M
authors.lastname: Hasebe
authors.forename: Minoru
authors.initials: M
authors.lastname: Kubo
mesh_terms: D016590:Aphidicolin / Q000494:pharmacology; D001483:Base Sequence; D019068:Bryopsida / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D054337:Cell Dedifferentiation / Q000502:physiology*; D056741:Cyclin D / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018744:DNA, Plant / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013234:Stem Cells / Q000502:physiology; D013997:Time Factors; D015533:Transcriptional Activation / Q000502:physiology
chemical_list: D056741:Cyclin D; D018744:DNA, Plant; D004791:Enzyme Inhibitors; D010940:Plant Proteins; D016590:Aphidicolin; D018844:Cyclin-Dependent Kinases