title: The expression of the clock gene cycle has rhythmic pattern and is affected by photoperiod in the moth Sesamia nonagrioides.
abstract: To obtain clues to the link between the molecular mechanism of circadian and photoperiod clocks, we have cloned the circadian clock gene cycle (Sncyc) in the corn stalk borer, Sesamia nonagrioides, which undergoes facultative diapause controlled by photoperiod. Sequence analysis revealed a high degree of conservation among insects for this gene. SnCYC consists of 667 amino acids and structural analysis showed that it contains a BCTR domain in its C-terminal in addition to the common domains found in Drosophila CYC, i.e. bHLH, PAS-A, PAS-B domains. The results revealed that the sequence of Sncyc showed a similarity to that of its mammalian orthologue, Bmal1. We also investigated the expression patterns of Sncyc in the brain of larvae growing under long-day 16L: 8D (LD), constant darkness (DD) and short-day 10L: 14D (SD) conditions using qRT-PCR assays. The mRNAs of Sncyc expression was rhythmic in LD, DD and SD cycles. Also, it is remarkable that the photoperiodic conditions affect the expression patterns and/or amplitudes of circadian clock gene Sncyc. This gene is associated with diapause in S. nonagrioides, because under SD (diapause conditions) the photoperiodic signal altered mRNA accumulation. Sequence and expression analysis of cyc in S. nonagrioides shows interesting differences compared to Drosophila where this gene does not oscillate or change in expression patterns in response to photoperiod, suggesting that this species is an interesting new model to study the molecular control of insect circadian and photoperiodic clocks.
authors.affiliation: Department of Biotechnology, School of Food, Biotechnology and Development Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kontogiannatos
authors.affiliation: Department of Biotechnology, School of Food, Biotechnology and Development Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Gkouvitsas
authors.affiliation: Department of Biotechnology, School of Food, Biotechnology and Development Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece. Electronic address: akourti@aua.gr.
authors.forename: Anna
authors.initials: A
authors.lastname: Kourti
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D056926:CLOCK Proteins / Q000235:genetics*; D057906:Circadian Clocks / Q000235:genetics*; D002940:Circadian Rhythm / Q000502:physiology*; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000235:genetics*; D009036:Moths; D017440:Photoperiod; D010802:Phylogeny; D012333:RNA, Messenger; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D019476:Insect Proteins; D012333:RNA, Messenger; D056926:CLOCK Proteins
keywords: Circadian clock; Diapause; Photoperiodism; Sesamia nonagrioides; cycle