Pigment-dispersing factor affects nocturnal activity rhythms, photic entrainment, and the free-running period of the circadian clock in the cricket gryllus bimaculatus.
Pigment-dispersing factor (PDF) is a neuropeptide widely distributed in insect brains and plays important roles in the circadian system. In this study, we used RNA interference to study the role of the pigment-dispersing factor (pdf) gene in regulating circadian locomotor rhythms in the cricket, Gryllus bimaculatus. Injections of pdf double-stranded RNA (dspdf) effectively knocked down the pdf mRNA and PDF peptide levels. The treated crickets maintained the rhythm both under light-dark cycles (LD) and constant darkness (DD). However, they showed rhythms with reduced nocturnal activity with prominent peaks at lights-on and lights-off. Entrainability of dspdf-injected crickets was higher than control crickets as they required fewer cycles to resynchronize to the LD cycles shifted by 6 h. The free-running periods of the dspdf-injected crickets were shorter than those of control crickets in DD. These results suggest that PDF is not essential for the rhythm generation but involved in control of the nocturnality, photic entrainment, and fine tuning of the free-running period of the circadian clock.
Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
Ehab
E
Hassaneen
Alaa
A
El-Din Sallam
Ahmad
A
Abo-Ghalia
Yoshiyuki
Y
Moriyama
Svetlana G
SG
Karpova
Salah
S
Abdelsalam
Ayami
A
Matsushima
Yasuyuki
Y
Shimohigashi
Kenji
K
Tomioka
D000818:Animals; D001522:Behavior, Animal; D001683:Biological Clocks; D002940:Circadian Rhythm; D029721:Drosophila Proteins / Q000378:metabolism*; D006135:Gryllidae; D007150:Immunohistochemistry; D019476:Insect Proteins / Q000378:metabolism*; D008027:Light; D008297:Male; D009068:Movement; D009479:Neuropeptides / Q000737:chemistry* / Q000378:metabolism; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D013997:Time Factors
D029721:Drosophila Proteins; D019476:Insect Proteins; D009479:Neuropeptides; C507073:PDFR protein, Drosophila; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled