Developmental Control of Cell-Cycle Compensation Provides a Switch for Patterned Mitosis at the Onset of Chordate Neurulation.
During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis.
Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan. Electronic address: ogura@cdb.riken.jp.
Yosuke
Y
Ogura
Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan.
Yasunori
Y
Sasakura
D000818:Animals; D002453:Cell Cycle / Q000502:physiology*; D043344:Chordata / Q000378:metabolism; D002938:Ciona intestinalis; D016195:G2 Phase / Q000502:physiology; D008938:Mitosis / Q000502:physiology*; D009024:Morphogenesis / Q000502:physiology*; D054261:Neurulation / Q000502:physiology*; D016196:S Phase / Q000502:physiology; D020687:cdc25 Phosphatases / Q000378:metabolism*
D020687:cdc25 Phosphatases