Pigment dispersing factor: An output regulator of the circadian clock in the German cockroach

Chi Mei Lee, Ming-Tsan Su, How Jing Lee*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


Pigment-dispersing factor (PDF) is a neuropeptide that is synthesized specifically and constantly in the circadian clock cells of many insects. The functions of PDF have not been fully determined, but it might serve as the output and coupling signal of circadian locomotor rhythms. In this experiment, we explore the functions of PDF in the German cockroach with RNA interference technique. Since the 2nd day after pdf double-strand RNA (dsRNA) injection, the amount of pdf mRNA decreased significantly, and this knockdown effect could persist at least 56 days. With immunostaining technique, the clock cells of pdf dsRNA-injected cockroaches could not be stained by anti-PDF antibody. In the behavioral study, pdf dsRNA injection caused rhythmic males to become arrhythmic in light-dark cycles or in constant darkness. In addition, due to the nocturnal nature of the German cockroaches, the locomotor activity increased after lights-off or entering subjective night. However, this activity peak gradually disappeared after pdf dsRNA injection. Based on these 2 lines of evidences, PDF serves as an output regulator of locomotor circadian rhythm in the German cockroach.

Original languageEnglish
Pages (from-to)35-43
Number of pages9
JournalJournal of Biological Rhythms
Issue number1
Publication statusPublished - 2009 Feb 1


  • Blattella germanica
  • Circadian rhythm
  • Gene silencing
  • Locomotion
  • Neuropeptides
  • RNA interference

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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