Circadian System Controlling Release of Sperm in the Insect Testes

Giebultowicz, J. M.; Riemann, John G.; Raina, Ashok K.; Ridgway, R. L.

doi:10.1126/science.245.4922.1098

Cited by 107 publications

(56 citation statements)

References 21 publications

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“…29). In the gypsy moth, a circadian rhythm of sperm release and transfer has been shown to operate via an autonomous photoreceptive pacemaker located in the testes-vas deferens complex (30). There are indications that fly testes may have such a clock function.…”

Section: Methodsmentioning

confidence: 99%

Novel Gq alpha isoform is a candidate transducer of rhodopsin signaling in a Drosophila testes-autonomous pacemaker.

Álvarez¹,

Robison²,

Gilbert³

1996

Proc. Natl. Acad. Sci. U.S.A.

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DGq is the alpha subunit of the heterotrimeric GTPase (Ga), which couples rhodopsin to phospholipase C in Drosophila vision. We have uncovered three duplicated exons in dgq by scanning the GenBank data base for unrecognized coding sequences. These alternative exons encode sites involved in GTPase activity and G13-binding, NorpA (phospholipase C)-binding, and rhodopsin-binding. We examined the in vivo splicing of dgq in adult flies and find that, in all but the male gonads, only two isoforms are expressed. One, dgqA, is the original visual isoform and is expressed in eyes, ocelli, brain, and male gonads. The other, dgqB, has the three novel exons and is widely expressed. Remarkably, all three nonvisual B exons are highly similar (82% identity at the amino acid level) to the Gqa family consensus, from Caenorhabditis elegans to human, but all three visual A exons are divergent (61% identity). Intriguingly, we have found a third isoform, dgqC, which is specifically and abundantly expressed in male gonads, and shares the divergent rhodopsin-binding exon of dgqA. We suggest that DGqC is a candidate for the light-signal transducer of a testes-autonomous photosensory clock. This proposal is supported by the finding that rhodopsin 2 and arrestin 1, two photoreceptor-cell-specific genes, are also expressed in male gonads.

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Section: Methodsmentioning

confidence: 99%

Novel Gq alpha isoform is a candidate transducer of rhodopsin signaling in a Drosophila testes-autonomous pacemaker.

Álvarez¹,

Robison²,

Gilbert³

1996

Proc. Natl. Acad. Sci. U.S.A.

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“…One prominent example was found in moths in which an autonomous circadian system in male reproductive organs orchestrates orderly succession of physiological processes vital for the survival of the species (Giebultowicz et al 1989). The testis^vas deferens complex of male moths displays many coordinated rhythms associated with a daily cycle of sperm release and maturation, as schematically depicted in ¢gure 1.…”

Section: Where Is the Physiology?mentioning

confidence: 99%

“…A second criterion that would make self-sustained clocks potentially independent from the rest of the body is the ability to be entrained directly by environmental signals. One of the ¢rst tissues identi¢ed in an insect that ful¢lled both criteria is the testes^vas deferens complex in the gypsy moth in which output rhythms of sperm release (discussed below) continue and are light-entrainable in vitro (Giebultowicz et al 1989). Recently, an avalanche of putative oscillators have been demonstrated in D. melanogaster transformed with luciferase, which acts as a real-time reporter for per and tim activities (Brandes et al 1996;Stanewsky et al 1998).…”

Section: Self-sustained and Photoresponsive Oscillators In Peripheralmentioning

confidence: 99%

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Peripheral clocks and their role in circadian timing: insights from insects

Giebułtowicz

2001

Phil. Trans. R. Soc. Lond. B

104

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Impressive advances have been made recently in our understanding of the molecular basis of the cellautonomous circadian feedback loop; however, much less is known about the overall organization of the circadian systems. How many clocks tick in a multicellular animal, such as an insect, and what are their roles and the relationships between them? Most attempts to locate clock-containing tissues were based on the analysis of behavioural rhythms and identi¢ed brain-located timing centres in a variety of animals. Characterization of several essential clock genes and analysis of their expression patterns revealed that molecular components of the clock are active not only in the brain, but also in many peripheral organs of Drosophila and other insects as well as in vertebrates. Subsequent experiments have shown that isolated peripheral organs can maintain self-sustained and light sensitive cycling of clock genes in vitro. This, together with earlier demonstrations that physiological output rhythms persist in isolated organs and tissues, provide strong evidence for the existence of functionally autonomous local circadian clocks in insects and other animals. Circadian systems in complex animals may include many peripheral clocks with tissue-speci¢c functions and a varying degree of autonomy, which seems to be correlated with their sensitivity to external entraining signals.

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“…Thus, the optic lobe is a prime candidate for the site of the circadian oscillator that regulates olfactory learning. However, there is compelling evidence from other insects (34,35) and cockroaches (29,36) that multiple, anatomically distributed oscillators exist, and it is plausible that these oscillators may influence learning and memory processes. In this context, it is interesting to note that recent experiments have shown that in Aplysia the well known circadian pacemaker in the eye is dispensable to the circadian regulation of long-term memory formation (37).…”

Section: Memory Acquisition Vs Memory Retrievalmentioning

confidence: 99%

Circadian regulation of insect olfactory learning

Decker

McConnaughey

Page

2007

Proc. Natl. Acad. Sci. U.S.A.

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Olfactory learning in insects has been used extensively for studies on the neurobiology, genetics, and molecular biology of learning and memory. We show here that the ability of the cockroach Leucophaea maderae to acquire olfactory memories is regulated by the circadian system. We investigated the effect of training and testing at different circadian phases on performance in an odordiscrimination test administered 30 min after training (short-term memory) or 48 h after training (long-term memory). When odor preference was tested by allowing animals to choose between two odors (peppermint and vanilla), untrained cockroaches showed a clear preference for vanilla at all circadian phases, indicating that there was no circadian modulation of initial odor preference or ability to discriminate between odors. After differential conditioning, in which peppermint odor was associated with a positive unconditioned stimulus of sucrose solution and vanilla odor was associated with a negative unconditioned stimulus of saline solution, cockroaches conditioned in the early subjective night showed a strong preference for peppermint and retained the memory for at least 2 days. Animals trained and tested at other circadian phases showed significant deficits in performance for both short-and long-term memory. Performance depended on the circadian time (CT) of training, not the CT of testing, and results indicate that memory acquisition rather than retention or recall is modulated by the circadian system. The data suggest that the circadian system can have profound effects on olfactory learning in insects.biological rhythms ͉ cockroach ͉ differential conditioning ͉ memory I n view of the widespread effects of circadian regulation on behavior and physiology, the possibility that learning and memory processes may be subject to modulation by the circadian system has long been recognized (1). Studies on this problem have suggested that the influence of the circadian system may take several forms. In some instances, the circadian phase may function as a context for learning (time stamping) so that recall and performance are better at 24-h intervals after learning (1-4). In other cases, performance may be modulated by the circadian phase independent of the phase of learning (5), and there have been several recent reports that memory acquisition or consolidation may depend on the circadian phase of training in mollusks (6-8), rodents (9, 10), and humans (11). Finally, there have been reports that disruption of the circadian system by phase shifting (jet lag) can impair memory (12, 13). Although these studies suggest that the circadian system may have widespread effects on various aspects of learning and memory, including acquisition, retention, and recall, there is virtually no information on the mechanisms by which the circadian system regulates these processes.Olfactory learning is an excellent model for exploration of the neural basis of learning and memory because of the remarkable similarity in the organization of olfactory systems acr...

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Circadian System Controlling Release of Sperm in the Insect Testes

Cited by 107 publications

References 21 publications

Novel Gq alpha isoform is a candidate transducer of rhodopsin signaling in a Drosophila testes-autonomous pacemaker.

Novel Gq alpha isoform is a candidate transducer of rhodopsin signaling in a Drosophila testes-autonomous pacemaker.

Peripheral clocks and their role in circadian timing: insights from insects

Circadian regulation of insect olfactory learning

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