Why are quiescent mesophyll protoplasts from Nicotiana sylvestris able to re-enter into the cell cycle and re-initiate a mitotic activity?
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.
Durr
A
A
Institut de Biologie Moléculaire des Plantes du CNRS, Strasbourg, France.
Jamet
E
E
Criqui
M C
MC
Genschik
P
P
Parmentier
Y
Y
Marbach
J
J
Plesse
B
B
Lett
M C
MC
Vernet
T
T
Fleck
J
J
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
D014452:Ubiquitins