Circadian clocks are timing devices that rhythmically adjust organism's behavior, physiology, and metabolism to the 24-h day-night cycle. Eukaryotic circadian clocks rely on several interlocked transcription-translation feedback loops, where protein stability is the key part of the delay between transcription and the appearance of the mature proteins within the feedback loops. In bilaterian animals, including mammals and insects, the circadian clock depends on a homologous set of proteins. Despite mostly conserved clock components among the fruit fly Drosophila and mammals, several lineage-specific differences exist. Here we have systematically explored the evolution and sequence variability of insect DBT proteins and their vertebrate homologs casein kinase 1 delta (CKIδ) and epsilon (CKIε), dated the origin and separation of CKIδ from CKIε, and identified at least three additional independent duplications of the CKIδ/ε gene in Petromyzon, Danio, and Xenopus. We determined conserved regions in DBT specific to Diptera, and functionally tested a subset of those in D. melanogaster. Replacement of Lysine K224 with acidic residues strongly impacts the free-running period even in heterozygous flies, whereas homozygous mutants are not viable. K224D mutants have a temperature compensation defect with longer free-running periods at higher temperatures, which is exactly the opposite trend of what was reported for corresponding mammalian mutants. All DBTs of dipteran insects contain the NKRQK motif at positions 220-224. The occurrence of this motif perfectly correlates with the presence of BRIDE OF DOUBLETIME, BDBT, in Diptera. BDBT is a non-canonical FK506-binding protein that physically interacts with Drosophila DBT. The phylogeny of FK506-binding proteins suggests that BDBT is either absent or highly modified in non-dipteran insects. In addition to in silico analysis of DBT/CKIδ/ε evolution and diversity, we have identified four novel casein kinase 1 genes specific to the Drosophila genus.
- Publikační typ
- časopisecké články MeSH
Circadian clocks orchestrate daily activity patterns and free running periods of locomotor activity under constant conditions. While the first often depends on temperature, the latter is temperature-compensated over a physiologically relevant range. Here, we explored the locomotor activity of the temperate housefly Musca domestica Under low temperatures, activity was centered round a major and broad afternoon peak, while high temperatures resulted in activity throughout the photophase with a mild midday depression, which was especially pronounced in males exposed to long photoperiods. While period (per) mRNA peaked earlier under low temperatures, no temperature-dependent splicing of the last per 3' end intron was identified. The expression of timeless, vrille, and Par domain protein 1 was also influenced by temperature, each in a different manner. Our data indicated that comparable behavioral trends in daily activity distribution have evolved in Drosophila melanogaster and M. domestica, yet the behaviors of these two species are orchestrated by different molecular mechanisms.
- MeSH
- 3' nepřekládaná oblast genetika MeSH
- časové faktory MeSH
- cirkadiánní rytmus genetika MeSH
- Drosophila melanogaster genetika MeSH
- exony genetika MeSH
- fotoperioda MeSH
- fylogeneze MeSH
- hmyzí geny * MeSH
- introny genetika MeSH
- kondiční příprava zvířat MeSH
- kryptochromy genetika MeSH
- messenger RNA genetika metabolismus MeSH
- moucha domácí MeSH
- pohybová aktivita MeSH
- promotorové oblasti (genetika) genetika MeSH
- regulace genové exprese MeSH
- sestřih RNA genetika MeSH
- teplota * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The aliphatic nitroalkene (E)-1-nitropentadec-1-ene (NPD), reported in early seventies in soldiers of the termite genus Prorhinotermes, was the first documented nitro compound produced by insects. Yet, its biosynthetic origin has long remained unknown. Here, we investigated in detail the biosynthesis of NPD in P. simplex soldiers. First, we track the dynamics in major metabolic pathways during soldier ontogeny, with emphasis on likely NPD precursors and intermediates. Second, we propose a hypothesis of NPD formation and verify its individual steps using in vivo incubations of putative precursors and intermediates. Third, we use a de novo assembled RNA-Seq profiles of workers and soldiers to identify putative enzymes underlying NPD formation. And fourth, we describe the caste- and age-specific expression dynamics of candidate initial genes of the proposed biosynthetic pathway. Our observations provide a strong support to the following biosynthetic scenario of NPD formation, representing an analogy of the sphingolipid pathway starting with the condensation of tetradecanoic acid with l-serine and leading to the formation of a C16 sphinganine. The C16 sphinganine is then oxidized at the terminal carbon to give rise to 2-amino-3-hydroxyhexadecanoic acid, further oxidized to 2-amino-3-oxohexadecanoic acid. Subsequent decarboxylation yields 1-aminopentadecan-2-one, which then proceeds through six-electron oxidation of the amino moiety to give rise to 1-nitropentadecan-2-one. Keto group reduction and hydroxyl moiety elimination lead to NPD. The proposed biosynthetic sequence has been constructed from age-related quantitative dynamics of individual intermediates and confirmed by the detection of labeled products downstream of the administered labeled intermediates. Comparative RNA-Seq analyses followed by qRT-PCR validation identified orthologs of serine palmitoyltransferase and 3-ketodihydrosphingosine reductase genes as highly expressed in the NPD production site, i.e. the frontal gland of soldiers. A dramatic onset of expression of the two genes in the first days of soldier's life coincides with the start of NPD biosynthesis, giving further support to the proposed biosynthetic hypothesis.
- MeSH
- alkoholoxidoreduktasy metabolismus MeSH
- aminokyseliny metabolismus MeSH
- hmyzí proteiny metabolismus MeSH
- Isoptera metabolismus MeSH
- ketony metabolismus MeSH
- mastné kyseliny metabolismus MeSH
- metabolom MeSH
- nitroparafiny metabolismus MeSH
- serin-C-palmitoyltransferasa metabolismus MeSH
- sfingolipidy metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Circadian clocks keep organisms in synchrony with external day-night cycles. The free running period (FRP) of the clock, however, is usually only close to-not exactly-24 h. Here, we explored the geographical variation in the FRP of the linden bug, Pyrrhocoris apterus, in 59 field-lines originating from a wide variety of localities representing geographically different environments. We have identified a remarkable range in the FRPs between field-lines, with the fastest clock at ~21 h and the slowest close to 28 h, a range comparable to the collections of clock mutants in model organisms. Similarly, field-lines differed in the percentage of rhythmic individuals, with a minimum of 13.8% and a maximum of 86.8%. Although the FRP correlates with the latitude and perhaps with the altitude of the locality, the actual function of this FRP diversity is currently unclear. With the recent technological progress of massive parallel sequencing and genome editing, we can expect remarkable progress in elucidating the genetic basis of similar geographic variants in P. apterus or in similar emerging model species of chronobiology.
- MeSH
- časové faktory MeSH
- cirkadiánní hodiny fyziologie MeSH
- cirkadiánní rytmus fyziologie MeSH
- fylogeneze MeSH
- Heteroptera klasifikace genetika fyziologie MeSH
- pohybová aktivita fyziologie MeSH
- Tilia parazitologie MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Geografické názvy
- Evropa MeSH
- Izrael MeSH
- východní Evropa MeSH
Adult reproductive diapause is characterized by lower behavioral activity, ceased reproduction and absence of juvenile hormone (JH). The role of JH receptor Methoprene-tolerant (Met) in female reproduction is well established; however, its function in male reproductive development and behavior is unclear. In the bean bug, Riptortus pedestris, circadian genes are essential for mediating photoperiodically-dependent growth of the male accessory glands (MAGs). The present study explores the role of circadian genes and JH receptor in male diapause in the linden bug, Pyrrhocoris apterus. These data indicate that circadian factors Clock, Cycle and Cry2 are responsible for photoperiod measurement, whereas Met and its partner protein Taiman participate in JH reception. Surprisingly, knockdown of the JH receptor neither lowered locomotor activity nor reduced mating behavior of males. These data suggest existence of a parallel, JH-independent or JH-upstream photoperiodic regulation of reproductive behavior.
- MeSH
- fotoperioda * MeSH
- Heteroptera růst a vývoj fyziologie MeSH
- juvenilní hormony metabolismus MeSH
- lokomoce MeSH
- methopren metabolismus MeSH
- sexuální chování zvířat MeSH
- signální transdukce * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The ability to perceive geomagnetic fields (GMFs) represents a fascinating biological phenomenon. Studies on transgenic flies have provided evidence that photosensitive Cryptochromes (Cry) are involved in the response to magnetic fields (MFs). However, none of the studies tackled the problem of whether the Cry-dependent magnetosensitivity is coupled to the sole MF presence or to the direction of MF vector. In this study, we used gene silencing and a directional MF to show that mammalian-like Cry2 is necessary for a genuine directional response to periodic rotations of the GMF vector in two insect species. Longer wavelengths of light required higher photon fluxes for a detectable behavioral response, and a sharp detection border was present in the cyan/green spectral region. Both observations are consistent with involvement of the FADox, FAD(•-) and FADH(-) redox forms of flavin. The response was lost upon covering the eyes, demonstrating that the signal is perceived in the eye region. Immunohistochemical staining detected Cry2 in the hemispherical layer of laminal glia cells underneath the retina. Together, these findings identified the eye-localized Cry2 as an indispensable component and a likely photoreceptor of the directional GMF response. Our study is thus a clear step forward in deciphering the in vivo effects of GMF and supports the interaction of underlying mechanism with the visual system.
- MeSH
- fenotyp MeSH
- fotoreceptory bezobratlých metabolismus účinky záření MeSH
- kryptochromy metabolismus MeSH
- magnetické pole * MeSH
- složené oko členovců účinky záření MeSH
- švábi metabolismus účinky záření MeSH
- ultrafialové záření MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Homologous circadian genes are found in all insect clocks, but their contribution to species-specific circadian timing systems differs. The aim of this study was to extend research within Lepidoptera to gain a better understanding of the molecular mechanism underlying circadian clock plasticity and evolution. The Mediterranean flour moth, Ephestia kuehniella (Pyralidae), represents a phylogenetically ancestral lepidopteran species. We have identified circadian rhythms in egg hatching, adult emergence, and adult locomotor activity. Cloning full-length complementary DNAs and further characterization confirmed one copy of period and timeless genes in both sexes. Both per and tim transcripts oscillate in their abundance in E. kuehniella heads under light-dark conditions. PER-like immunoreactivity (PER-lir) was observed in nuclei and cytoplasm of most neurons in the central brain, the ventral part of subesophageal complex, the neurohemal organs, the optic lobes, and eyes. PER-lir in photoreceptor nuclei oscillated during the day with maximal intensity in the light phase of the photoperiodic regime and lack of a signal in the middle of the dark phase. Expression patterns of per and tim messenger RNAs (mRNAs) were revealed in the identical location as the PER-lir was detected. In the photoreceptors, a daily rhythm in the intensity of expression of both per mRNA and tim mRNA was found. These findings suggest E. kuehniella as a potential lepidopteran model for circadian studies.
- MeSH
- biologické hodiny genetika MeSH
- cirkadiánní hodiny genetika MeSH
- cirkadiánní proteiny Period genetika metabolismus MeSH
- cirkadiánní rytmus genetika fyziologie MeSH
- fenotyp MeSH
- fotoperioda MeSH
- hmyzí proteiny genetika MeSH
- hybridizace in situ MeSH
- imunohistochemie MeSH
- jaderné proteiny metabolismus MeSH
- klonování organismů MeSH
- komplementární DNA MeSH
- messenger RNA genetika metabolismus MeSH
- mozek metabolismus MeSH
- můry genetika růst a vývoj fyziologie MeSH
- regulace genové exprese MeSH
- sekvenční analýza DNA MeSH
- světlo MeSH
- zrakový lalok nesavčí fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH