Circadian clock in Ciona intestinalis revealed by microarray analysis and oxygen consumption

Toshifumi Minamoto, Shuji Hanai, Koji Kadota, Katsutaka Oishi, Hiromi Matsumae, Manabu Fujie, Kaoru Azumi, Noriyuki Satoh, Masanobu Satake, Norio Ishida

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


The molecular mechanisms of the endogenous circadian clocks that allow most animals to adapt to environmental cycles have recently been uncovered. The draft genome of the ascidian, Ciona intestinalis, a model animal that is close to vertebrates, has been described. However, the C. intestinalis genome lacks the canonical clock genes such as Per, Bmal and Clock that are shared by vertebrates and insects. Here, we found the circadian rhythms at the physiological and molecular levels. The oxygen consumption rate was lower during the light phase and higher during the dark phase during a day, and the rhythm highly damped and continued under constant darkness. From the microarray analysis, the 396 spots (1.8% of the total; corresponding to 388 clones) were extracted as candidates for circadian expression. We confirmed the circadian expression of several candidate genes by northern blotting. Furthermore, three of four rhythmic expressed genes showed phase-shifts to prolonged light period. However, most of known clock genes did not oscillate. These data suggest that C. intestinalis have a unique molecular circadian clock and the daily environmental change is not such a strong effect for sea squirt in its evolution when compared to vertebrates and insects.

Original languageEnglish
Pages (from-to)175-184
Number of pages10
JournalJournal of biochemistry
Issue number2
Publication statusPublished - 2010 Feb
Externally publishedYes


  • Ascidian
  • Ciona intestinalis
  • Circadian clock
  • Microarray
  • Northern blotting

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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