| 1. |
- Dircksen, Heinrich, et al.
(författare)
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Differential neuronal expression of three Drosophila ion transport peptide splice forms indicate multiple functions of peptidergic neurons
- 2009
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Ingår i: Comparative Biochemistry and Physiology A. - : Elsevier BV. - 1095-6433 .- 1531-4332. ; 153A:2, suppl. 1, s. S79-
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Tidskriftsartikel (refereegranskat)abstract
- We identified previously two long (DrmITPL1 and -L2) and one amidated short isoform (DrmITP) of insect ion transport peptides (ITPs) as products derived by alternatively splicing from the Drosophila itp-gene (CG13586). The peptides are members of a large family of arthropod neuropeptides incl. crustacean hyperglycemic hormones (CHH/ITP-family), but similar ITPs are only known in locusts to have antidiuretic bioactivity on the hindgut. We localised the peptides by in situ hybridisation and immunocytochemistry with isoform-specific antibodies in the nervous system of larval (L3) and adult Drosophila melanogaster and screened Gal4-lines specific for peptidergic cells. Four neurosecretory cells in brain-corpora cardiaca/allata putatively release DrmITP as a hormone in all stages. DrmITP also occurs in interneurons in the brain/ventral ganglia and in neurons efferent towards the hindgut. Some interneurons are identical to well-known circadian clock neurons for which the effector molecules were elusive but are responsible for the evening bouts of locomotor activity in flies. DrmITPL1 and -L2 were found only in peripheral lateral bipolar and putative sensory neurons which are likely to play a role in the control of growth, hindgut ion transport and heart beat. With DrmITP identified in brain neurosecretory cells, hindgut-innervating neurons in the abdominal ganglia and one pair in the abdomen close to the larval anal organ or innervating the adult rectal pads, both chloride-transporting organs, we are facing an enormous complexity in multiple functions of differentially expressed ITP/Ls derived from a single gene. Preliminary results using Gal4-driven RNAi in distinct peptidergic neurons look promising to find deficiency phenotypes.
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| 2. |
- Dircksen, Heinrich, 1954-, et al.
(författare)
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Ion transport peptide splice forms in central and peripheral neurons throughout postembryogenesis of Drosophila melanogaster.
- 2008
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Ingår i: The Journal of comparative neurology. - : Wiley. - 1096-9861 .- 0021-9967. ; 509:1, s. 23-41
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Tidskriftsartikel (refereegranskat)abstract
- Ion transport peptides (ITPs) belong to a large arthropod neuropeptide family including crustacean hyperglycaemic hormones and are antidiuretic hormones in locusts. Because long and short ITP isoforms are generated by alternative splicing from a single gene in locusts and moths, we investigated whether similarly spliced gene products occur in the nervous system of Drosophila melanogaster throughout postembryogenesis. The itp gene CG13586 was reanalyzed, and we found three instead of the two previously annotated alternatively spliced mRNAs. These give rise to three different neuropeptides, two long C-terminally carboxylated isoforms (DrmITPL1 and DrmITPL2, both 87 amino acids) and one short amidated DrmITP (73 amino acids), which were partially identified biochemically. Immunocytochemistry and in situ hybridization reveal nine larval and 14 adult identified neurons: four pars lateralis neurosecretory neurons, three hindgut-innervating neurons in abdominal ganglia, and a stage-specific number of interneurons and peripheral bipolar neurons. The neurosecretory neurons persist throughout postembryogenesis, form release sites in corpora cardiaca, and invade corpora allata. One type of ITP-expressing interneuron exists only in the larval and prepupal subesophageal ganglia, whereas three types of interneurons in the adult brain arise in late pupae and invade circumscribed neuropils in superior median and lateral brain areas. One peripheral bipolar and putative sensory neuron type occurs in the larval, pupal, and adult preterminal abdominal segments. Although the neurosecretory neurons may release DrmITP and DrmITPL2 into the haemolymph, possible physiological roles of the hindgut-innervating and peripheral neurons as well as the interneurons are yet to be identified.
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| 3. |
- Enell, Lina, et al.
(författare)
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gamma-Aminobutyric acid (GABA) signaling components in Drosophila : immunocytochemical localization of GABA(B) receptors in relation to the GABA(A) receptor subunit RDL and a vesicular GABA transporter.
- 2007
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967 .- 1096-9861. ; 505:1, s. 18-31
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Tidskriftsartikel (refereegranskat)abstract
- γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in insects and is widely distributed in the central nervous system (CNS). GABA acts on ion channel receptors (GABAAR) for fast inhibitory transmission and on G-protein-coupled ones (GABABR) for slow and modulatory action. We used immunocytochemistry to map GABABR sites in the Drosophila CNS and compared the distribution with that of the GABAAR subunit RDL. To identify GABAergic synapses, we raised an antiserum to the vesicular GABA transporter (vGAT). For general GABA distribution, we utilized an antiserum to glutamic acid decarboxylase (GAD1) and a gad1-GAL4 to drive green fluorescent protein. GABABR-immunoreactive (IR) punctates were seen in specific patterns in all major neuropils of the brain. Most abundant labeling was seen in the mushroom body calyces, ellipsoid body, optic lobe neuropils, and antennal lobes. The RDL distribution is very similar to that of GABABR-IR punctates. However, the mushroom body lobes displayed RDL-IR but not GABABR-IR material, and there were subtle differences in other areas. The vGAT antiserum labeled punctates in the same areas as the GABABR and appeared to display presynaptic sites of GABAergic neurons. Various GAL4 drivers were used to analyze the relation between GABABR distribution and identified neurons in adults and larvae. Our findings suggest that slow GABA transmission is very widespread in the Drosophila CNS and that fast RDL-mediated transmission generally occurs at the same sites. J. Comp. Neurol. 505:18–31, 2007.
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| 4. |
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| 5. |
- Ignell, Rickard, et al.
(författare)
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Presynaptic peptidergic modulation of olfactory receptor neurons in Drosophila.
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:31, s. 13070-13075
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Tidskriftsartikel (refereegranskat)abstract
- The role of classical neurotransmitters in the transfer and processing of olfactory information is well established in many organisms. Neuropeptide action, however, is largely unexplored in any peripheral olfactory system. A subpopulation of local interneurons (LNs) in the Drosophila antannal lobe is peptidergic, expressing Drosophila tachykinins (DTKs). We show here that olfactory receptor neurons (ORNs) express the DTK receptor (DTKR). Using two-photon microscopy, we found that DTK applied to the antennal lobe suppresses presynaptic calcium and synaptic transmission in the ORNs. Furthermore, reduction of DTKR expression in ORNs by targeted RNA interference eliminates presynaptic suppression and alters olfactory behaviors. We detect opposite behavioral phenotypes after reduction and over expression of DTKR in ORNs. Our findings suggest a presynaptic inhibitory feedback to ORNs from peptidergic LNs in the antennal lobe.
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| 6. |
- Jansen, Anna M, et al.
(författare)
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PICK1 expression in the Drosophila central nervous system primarily occurs in the neuroendocrine system.
- 2009
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Ingår i: The Journal of comparative neurology. - : Wiley. - 1096-9861 .- 0021-9967. ; 517:3, s. 313-32
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Tidskriftsartikel (refereegranskat)abstract
- The protein interacting with C kinase 1 (PICK1) protein was first identified as a novel binding partner for protein kinase C. PICK1 contains a membrane-binding BAR domain and a PDZ domain interacting with many synaptic proteins, including the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor subunit GluR2 and the dopamine transporter. PICK1 is strongly implicated in GluR2 trafficking and synaptic plasticity. In mammals, PICK1 has been characterized extensively in cell culture studies. To study PICK1 in an intact system, we characterized PICK1 expression immunohistochemically in the adult and larval Drosophila central nervous system. PICK1 was found in cell bodies in the subesophageal ganglion, the antennal lobe, the protocerebrum, and the neuroendocrine center pars intercerebralis. The cell types that express PICK1 were identified using GAL4 enhancer trap lines. The PICK1-expressing cells form a subpopulation of neurons. PICK1 immunoreactivity was neither detected in glutamatergic nor in dopaminergic neurons. Also, we observed PICK1 expression in only a few GABAergic neurons, located in the antennal lobe. In contrast, we detected robust PICK1 immunolabeling of peptidergic neurons in the neuroendocrine system, which express the transcription factor DIMM and the amidating enzyme peptidylglycine-alpha-hydroxylating monooxygenase (PHM). The PICK1-positive cells include neurosecretory cells that produce the insulin-like peptide dILP2. PICK1 expression in insulin-producing cells also occurs in mammals, as it was also observed in a rat insulinoma cell line derived from pancreatic beta-cells. At the subcellular level, PICK1 was found in the perinuclear zone but surprisingly not in synaptic domains. We conclude that PICK1 may serve an important role in the neuroendocrine system both in insects and vertebrates.
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| 7. |
- Johard, Helena A D, et al.
(författare)
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Peptidergic clock neurons in Drosophila : ion transport peptide and short neuropeptide F in subsets of dorsal and ventral lateral neurons
- 2009
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Ingår i: The Journal of comparative neurology. - : Wiley. - 1096-9861 .- 0021-9967. ; 516:1, s. 59-73
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Tidskriftsartikel (refereegranskat)abstract
- About 150 clock neurons are clustered in different groups in the brain of Drosophila. Among these clock neurons, some pigment-dispersing factor (PDF)-positive and PDF-negative lateral neurons (LNs) are principal oscillators responsible for bouts of activity in the morning and evening, respectively. The full complement of neurotransmitters in these morning and evening oscillators is not known. By using a screen for candidate neuromediators in clock neurons, we discovered ion transport peptide (ITP) and short neuropeptide F (sNPF) as novel neuropeptides in subpopulations of dorsal (LN(d)s) and ventral (s-LN(v)s) LNs. Among the six LN(d)s, ITP was found in one that coexpresses long neuropeptide F (NPF) and cryptochrome. We detected sNPF in two LN(d)s that also express cryptochrome; these cells are distinct from three LN(d)s expressing NPF. Thus, we have identified neuropeptides in five of the six LN(d)s. The three LN(d)s expressing cryptochrome, with either ITP or sNPF, are the only ones with additional projections to the accessory medulla. Among the five s-LN(v)s in the adult brain, ITP was detected in the fifth neuron that is devoid of PDF and sNPF in the four neurons that also express PDF. By using a choline acetyltransferase (Cha) Gal4, we detected Cha expression in the two sNPF producing LN(d)s and in the fifth s-LN(v). In the larval brain, two of the four PDF-producing s-LN(v)s coexpress sNPF. Our findings emphasize that the LN(d)s are heterogeneous both anatomically and with respect to content of neuropeptides, cryptochrome, and other markers and suggest diverse functions of these neurons.
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| 8. |
- Kolodziejczyk, Agata, et al.
(författare)
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Glutamate, GABA and acetylcholine signaling components in the lamina of the Drosophila visual system
- 2008
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Ingår i: PLOS ONE. - 1932-6203. ; 3:5, s. e2110-
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Tidskriftsartikel (refereegranskat)abstract
- Synaptic connections of neurons in the Drosophila lamina, the most peripheral synaptic region of the visual system, have been comprehensively described. Although the lamina has been used extensively as a model for the development and plasticity of synaptic connections, the neurotransmitters in these circuits are still poorly known. Thus, to unravel possible neurotransmitter circuits in the lamina of Drosophila we combined Gal4 driven green fluorescent protein in specific lamina neurons with antisera to γ-aminobutyric acid (GABA), glutamic acid decarboxylase, a GABAB type of receptor, L-glutamate, a vesicular glutamate transporter (vGluT), ionotropic and metabotropic glutamate receptors, choline acetyltransferase and a vesicular acetylcholine transporter. We suggest that acetylcholine may be used as a neurotransmitter in both L4 monopolar neurons and a previously unreported type of wide-field tangential neuron (Cha-Tan). GABA is the likely transmitter of centrifugal neurons C2 and C3 and GABAB receptor immunoreactivity is seen on these neurons as well as the Cha-Tan neurons. Based on an rdl-Gal4 line, the ionotropic GABAA receptor subunit RDL may be expressed by L4 neurons and a type of tangential neuron (rdl-Tan). Strong vGluT immunoreactivity was detected in α-processes of amacrine neurons and possibly in the large monopolar neurons L1 and L2. These neurons also express glutamate-like immunoreactivity. However, antisera to ionotropic and metabotropic glutamate receptors did not produce distinct immunosignals in the lamina. In summary, this paper describes novel features of two distinct types of tangential neurons in the Drosophila lamina and assigns putative neurotransmitters and some receptors to a few identified neuron types.
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| 9. |
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| 10. |
- Poels, Jeroen, et al.
(författare)
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Characterization and distribution of NKD, a receptor for Drosophila tachykinin-related peptide 6.
- 2009
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 30:3, s. 545-56
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptides related to vertebrate tachykinins have been identified in Drosophila and are referred to as drosotachykinins, or DTKs. Two Drosophila G protein-coupled receptors, designated NKD (neurokinin receptor from Drosophila; CG6515) and DTKR (Drosophila tachykinin receptor; CG7887), display sequence similarities to mammalian tachykinin receptors. Whereas DTKR was shown to be activated by DTKs [Birse RT, Johnson EC, Taghert PH, Nässel DR. Widely distributed Drosophila G-protein-coupled receptor (CG7887) is activated by endogenous tachykinin-related peptides. J Neurobiol 2006;66:33-46; Poels J, Verlinden H, Fichna J, Van Loy T, Franssens V, Studzian K, et al. Functional comparison of two evolutionary conserved insect neurokinin-like receptors. Peptides 2007;28:103-8] and was localized by immunocytochemistry in Drosophila central nervous system (CNS), agonist-dependent activation and distribution of NKD have not yet been investigated in depth. In the present study, we have challenged NKD-expressing mammalian and insect cells with a library of Drosophila neuropeptides and discovered DTK-6 as a specific agonist that can induce a calcium response in these cells. In addition, we have produced antisera to sequences from NKD protein to analyze receptor distribution. We found that NKD is less abundantly distributed in the central nervous system than DTKR, and only NKD was found in the intestine. In fact, the two receptors are distributed in mutually exclusive patterns in the CNS. The combined distribution of the receptors in brain neuropils corresponds well with the distribution of DTKs. Most interestingly, NKD appears to be activated only by DTK-6, known to possess an Ala-substitution in an otherwise conserved C-terminal core motif. Our findings suggest that NKD and DTKR provide substrates for two functionally and spatially separated peptide signaling systems.
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| 11. |
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| 12. |
- Winther, Åsa M E, et al.
(författare)
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Peptidergic signaling in the antennal lobe modulates olfaction
- 2007
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Ingår i: 20th European Drosophila Research Coference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The dtk gene in Drosophila encodes five different neuropeptides designated Drosophila tachykinins (DTK 1-5) that are expressed in about 100 neurons in the brain. Two tachykinin receptors (DTKR and NKD) have been identified in Drosophila. Specific neurons of the antennal lobe (AL), the primary center for olfactory processing in the Drosophila brain, express DTKs and the receptor DTKR. The DTKs are colocalized with the inhibitory transmitter GABA in many of the local interneurons (LNs) of the AL. We have investigated the roles of DTKs and DTKR in olfactory behavior by interfering with DTK signaling. By employing the Gal4/UAS system we have directed overexpression or knock-down (using RNAi) of peptides or receptor to different neuron types of the AL. Olfactory behavior was tested in a trap-assay based on a choice of odorant or control. We tested flies with DTK deficiency in two different partly overlapping populations of LNs. We also tested flies that are virtually DTK null (driving the RNAi construct with the pan-neural elav-Gal4). DTK deficient flies were less attracted to some of the odors tested. To study the role of the DTKR we used Gal4 lines that drive expression in olfactory receptor neurons (ORNs), LNs and in projection neurons to overexpress (OE) or down-regulate the receptor. DTKR-OE in the ORNs resulted in flies more repelled (or less attracted) to some of the odors tested. DTKR-OE in a subpopulation of the LNs produced flies with the same behavioral phenotype. Flies with DTKR deficiency in the ORNs and LNs were more attracted to odors. Our results suggest that DTKs and DTKR are involved in the modulation of the response to odors at the levels of ORNs and LNs, possibly by modulating the inhibitory activity of GABA.
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