Role of timer and sizer in regulation of Chlamydomonas cell cycle

Kazunori Matsumura, Toshiki Yagi, Kenji Yasuda*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


To estimate the role that time and size had in controlling the Chlamydomonas cell cycle, we used a new on-chip single-cell microcultivation system, which involved the direct observation of single cells captured in microchambers made on a thin glass slide. The dependence of the pattern of energy supply for cells on its cell cycle was examined through a series of different intensities of continuous illumination in a minimal medium, and we found that cell division occurred when cells reached the critical size, which was 2.2 times larger than that of the newly created cells. When illumination stopped before cells reached the critical size, even though growth had stopped, they continued dividing during the delay time, which was shorter when cells were larger. With re-illumination after darkness, cells began to grow again and the timing of cell division was again controlled by the critical size. This indicates that the co-existence of two cell cycle regulation mechanisms and the sizer mechanism had a stronger influence than the timer.

Original languageEnglish
Pages (from-to)1042-1049
Number of pages8
JournalBiochemical and Biophysical Research Communications
Issue number4
Publication statusPublished - 2003 Jul 11
Externally publishedYes


  • Cell cycle
  • Chlamydomonas
  • Growth
  • Light intensity
  • Microcultivation
  • Photosynthesizing cells
  • Sizer
  • Timer

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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