title: Why are quiescent mesophyll protoplasts from Nicotiana sylvestris able to re-enter into the cell cycle and re-initiate a mitotic activity?
abstract: Mesophyll protoplasts of Nicotiana sylvestris incubated in an adequate culture medium re-enter very rapidly into the cell cycle and divide. The transition G0/G1 is accompanied by a complete reversion of the program of gene expression. The program of the photosynthetic differentiated mesophyll cell is abolished whereas a new multipartite program of a highly stressed but ready-to-divide cell is established. Some genes encode proteins which structure suggests they may play key roles in these events. Most of the induced genes are under multiple controls: stress and/or development. Stress response and cellular re-organization might thus be closely related events that cannot be dissociated. It is probable that the re-entry of a protoplast into the cell cycle, ie the initial step of totipotency, closely depends on the coordinated activation of a set of genes that share common regulatory mechanisms.
authors.affiliation: Institut de Biologie Moléculaire des Plantes du CNRS, Strasbourg, France.
authors.forename: A
authors.initials: A
authors.lastname: Durr
authors.forename: E
authors.initials: E
authors.lastname: Jamet
authors.forename: M C
authors.initials: MC
authors.lastname: Criqui
authors.forename: P
authors.initials: P
authors.lastname: Genschik
authors.forename: Y
authors.initials: Y
authors.lastname: Parmentier
authors.forename: J
authors.initials: J
authors.lastname: Marbach
authors.forename: B
authors.initials: B
authors.lastname: Plesse
authors.forename: M C
authors.initials: MC
authors.lastname: Lett
authors.forename: T
authors.initials: T
authors.lastname: Vernet
authors.forename: J
authors.initials: J
authors.lastname: Fleck
mesh_terms: D002453:Cell Cycle / Q000235:genetics; D002478:Cells, Cultured; D017343:Genes, Plant; D008938:Mitosis / Q000235:genetics; D010947:Plants, Toxic; D011523:Protoplasts / Q000166:cytology* / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology*; D014452:Ubiquitins / Q000502:physiology
chemical_list: D014452:Ubiquitins