担当区分：筆頭著者,　責任著者  

DOI： 10.5281/zenodo.20274875

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担当区分：筆頭著者   記述言語：英語  

DOI： 10.2139/ssrn.6839567

DOI： 10.5281/zenodo.20102020

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担当区分：筆頭著者  

DOI： 10.5281/zenodo.20102068

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担当区分：筆頭著者  

DOI： 10.5281/zenodo.20073572

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

In Drosophila males, the accessory gland is responsive to nutrient signal-dependent regulation of fertility/fecundity. The accessory gland is composed of two types of binucleated epithelial cells, about 1000 main cells and 60 secondary cells (SCs). The transcription factors Defective proventriculus (Dve), Abdominal-B, and Ecdysone receptors (EcRs) are strongly expressed in adult SCs. In response to nutrient conditions during development, coordinated action between Dve and ecdysone signaling determines the optimal number of SCs and regulates their maturation. A downstream effector of ecdysone signaling, Ftz-F1, is crucial in this process. Another downstream effector, Polished rice (Pri), is small peptides of 11 or 32 amino acids. Here we show that pri is required for maturation of SCs and for male fecundity, whereas it is not involved in determination of the number of SCs. We provide evidence that Pri acts downstream of Ftz-F1 to regulate maturation but not survival of SCs.

DOI： 10.1111/gtc.70025

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The circadian system comprises multiple clocks, including central and peripheral clocks. The central clock generally governs peripheral clocks to synchronize circadian rhythms throughout the animal body. However, whether the peripheral clock influences the central clock is unclear. This issue can be addressed through a system comprising a peripheral clock (compound eye clock [CE clock]) and central clock (the optic lobe [OL] clock) in the cricket Gryllus bimaculatus. We previously found that the compound eye regulates the free-running period (τ) and the stability of locomotor rhythms driven by the OL clock, as measured by the daily deviation of τ at 30°C. However, the role of the CE clock in this regulation remains unexplored. In this study, we investigated the importance of the CE clock in this regulation using RNA interference (RNAi) of the period (per) gene localized to the compound eye (perCE-RNAi). The perCE-RNAi abolished the compound eye rhythms of the electroretinogram (ERG) amplitude and clock gene expression but the locomotor rhythm driven by the OL clock was maintained. The locomotor rhythm of the tested crickets showed a significantly longer τ and greater daily variation of τ than those of control crickets treated with dsDsRed2. The variation of τ was comparable with that of crickets with the optic nerve severed. The τ was considerably longer but was comparable with that of crickets with the optic nerve severed. These results suggest that the CE clock regulates the OL clock to maintain and stabilize τ.

DOI： 10.2108/zs230113

PubMed

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

Steroid hormones play various physiological roles including metabolism and reproduction. Steroid hormones in insects are ecdysteroids, and the major form in Drosophila melanogaster is ecdysone. In Drosophila males, the accessory gland is responsive to nutrient-dependent regulation of fertility/fecundity. The accessory gland is composed of two types of binucleated epithelial cells: a main cell and a secondary cell (SC). The transcription factors Defective proventriculus (Dve), Abdominal-B, and Ecdysone receptors (EcRs) are strongly expressed in adult SCs. We show that this EcR expression is regulated by parallel pathways of nutrient signaling and the Dve activity. Induction of Dve expression is also dependent on nutrient signaling, and it becomes nutrient signal-independent during a restricted period of development. Forced dve expression during the restricted period significantly increased the number of SCs. Here, we provide evidence that the level of nutrient signal-dependent Dve expression during the restricted period determines the number of SCs, and that ecdysone signaling is also crucial to optimize male fecundity through nutrient signal-dependent survival and maturation of SCs.

DOI： 10.1016/j.ydbio.2024.01.004

PubMed

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Zoological Society of Japan  

Photic entrainment is an essential property of the circadian clock that sets the appropriate timing of daily behavioral and physiological events. However, the molecular mechanisms underlying the entrainment remain largely unknown. In the cricket Gryllus bimaculatus, the immediate early gene c-fosB plays an important role in photic entrainment, followed by a mechanism involving cryptochromes (crys). However, the association between c-fosB expression and crys remains unclear. In the present study, using RNA-sequencing analysis, we found that five Fbxl family genes (Fbxl4, Fbxl5, Fbxl16, Fbxl-like1, and Fbxl-like2) encoding F-box and leucine-rich repeat proteins are likely involved in the mechanism following light-dependent c-fosB induction. RNA interference (RNAi) of c-fosA/B significantly downregulated Fbxls expression, whereas RNAi of the Fbxl genes exerted no effect on c-fosB expression. The Fbxl genes showed rhythmic expression under light-dark cycles (LDs) with higher expression levels in early day (Fbxl16), whole day (Fbxl-like1), or day-to-early night (Fbxl4, Fbxl5, and Fbxl-like2), whereas their expression was reduced in the dark. We then examined the effect of their RNAi on the photic entrainment of the locomotor rhythm and found that RNAi of Fbxl4 either disrupted or significantly delayed the re-entrainment of the locomotor rhythm to shifted LDs. These results suggest that light-induced c-fosB expression stimulates Fbxl4 expression to reset the circadian clock.

DOI： 10.2108/zs220047

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Zoological Society of Japan  

The light cycle is the most powerful Zeitgeber entraining the circadian clock in most organisms. Insects use CRYPTOCHROMEs (CRYs) and/or the compound eye for the light perception necessary for photic entrainment. The molecular mechanism underlying CRY-dependent entrainment is well understood, while that of the compound eye-dependent entrainment remains to be elucidated. Using molecular and behavioral experiments, we investigated the role of timeless (tim) in the photic entrainment mechanism in the cricket Gryllus bimaculatus. RNA interference of tim (timRNAi) disrupted the entrainment or prolonged the transients for resynchronization to phase-delayed light-dark cycles. The treatment reduced the magnitude of phase delay caused by delayed light-off, but augmented advance shifts caused by light exposure at late night. TIM protein levels showed daily cycling with an increase during the night and reduction by light exposure at both early and late night. These results suggest that tim plays a critical role in the entrainment to delayed light cycles.

DOI： 10.2108/zs220011

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<title>Abstract</title>
The circadian clock generates rhythms of approximately 24 h through periodic expression of the clock genes. In insects, the major clock genes <italic>period</italic> (<italic>per</italic>) and <italic>timeless</italic> (<italic>tim</italic>) are rhythmically expressed upon their transactivation by CLOCK/CYCLE, with peak levels in the early night. In <italic>Drosophila</italic>, <italic>clockwork orange</italic> (<italic>cwo</italic>) is known to inhibit the transcription of <italic>per</italic> and <italic>tim</italic> during the daytime to enhance the amplitude of the rhythm, but its function in other insects is largely unknown. In this study, we investigated the role of <italic>cwo</italic> in the clock mechanism of the cricket <italic>Gryllus bimaculatus</italic>. The results of quantitative RT-PCR showed that under a light/dark (LD) cycle, <italic>cwo</italic> is rhythmically expressed in the optic lobe (lamina-medulla complex) and peaks during the night. When <italic>cwo</italic> was knocked down via RNA interference (RNAi), some crickets lost their locomotor rhythm, while others maintained a rhythm but exhibited a longer free-running period under constant darkness (DD). In <italic>cwo</italic>^RNAi crickets, all clock genes except for <italic>cryptochrome 2</italic> (<italic>cry2</italic>) showed arrhythmic expression under DD; under LD, some of the clock genes showed higher mRNA levels, and <italic>tim</italic> showed rhythmic expression with a delayed phase. Based on these results, we propose that <italic>cwo</italic> plays an important role in the cricket circadian clock.

DOI： 10.1186/s40851-020-00166-4

PubMed

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その他リンク： http://link.springer.com/article/10.1186/s40851-020-00166-4/fulltext.html

担当区分：筆頭著者  

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担当区分：筆頭著者   記述言語：英語   掲載種別：学位論文（博士）   出版者・発行元：Wiley  

Nutrient conditions affect the reproductive potential and lifespan of many organisms through the insulin signaling pathway. Although this is well characterized in female oogenesis, nutrient-dependent regulation of fertility/fecundity in males is not known. Seminal fluid components synthesized in the accessory gland are required for high fecundity in Drosophila males. The accessory gland is composed of two types of binucleated cells: a main cell and a secondary cell (SC). The transcription factors Defective proventriculus (Dve) and Abdominal-B (Abd-B) are strongly expressed in adult SCs, whose functions are essential for male fecundity. We found that gene expression of both Dve and Abd-B was down-regulated under nutrient-poor conditions. In addition, nutrient conditions during the pupal stage affected the size and number of SCs. These morphological changes clearly correlated with fecundity, suggesting that SCs act as nutrient sensors. Here, we provide evidence that Dve associates nutrient conditions with optimal reproductive potential in a target of rapamycin signaling-dependent manner.

DOI： 10.1111/gtc.12600

PubMed

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