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Identification of neuropeptides and evolutionarily conserved peptide receptors in Hydra
https://ir.soken.ac.jp/records/1025
https://ir.soken.ac.jp/records/10251a57e722-c88f-4005-9166-caad0bdc7718
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要旨・審査要旨 (293.9 kB)
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本文 (18.6 MB)
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| Item type | 学位論文 / Thesis or Dissertation(1) | |||||
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| 公開日 | 2010-02-22 | |||||
| タイトル | ||||||
| タイトル | Identification of neuropeptides and evolutionarily conserved peptide receptors in Hydra | |||||
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| タイトル | Identification of neuropeptides and evolutionarily conserved peptide receptors in Hydra | |||||
| 言語 | en | |||||
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| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_46ec | |||||
| 資源タイプ | thesis | |||||
| 著者名 |
早川, 英介
× 早川, 英介 |
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| フリガナ |
ハヤカワ, エイスケ
× ハヤカワ, エイスケ |
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| 著者 |
HAYAKAWA, Eisuke
× HAYAKAWA, Eisuke |
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| 学位授与機関 | ||||||
| 学位授与機関名 | 総合研究大学院大学 | |||||
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| 学位名 | 博士（理学） | |||||
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| 内容記述タイプ | Other | |||||
| 内容記述 | 総研大甲第1003号 | |||||
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| 値 | 生命科学研究科 | |||||
| 専攻 | ||||||
| 値 | 18 遺伝学専攻 | |||||
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| 学位授与年月日 | 2006-09-29 | |||||
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| 値 | 2006 | |||||
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| 内容記述タイプ | Other | |||||
| 内容記述 | Neuropeptides are utilized as transmitters and hormones in higher metazoans. In lower metazoans, the information of neuropeptides are still limited. Hydra, a member of Cnidaria, is one of the most basal metazoans that have a definite body plan and nervous system. It has been implicated that developmental processes and physiology of Hydra are highly regulated by various signaling peptides. Furthermore, neurotransmission in Cnidaria are thought to be performed exclusively with peptides. Thus, identification and characterization of neuropeptides are of particular importance to understand both development and physiology of Hydra. The information obtained from Hydra should also shed light on evolution of peptides and their receptors.<br /><br />Chapter Ⅰ Identification of evolutionarily conserved neuropeptides and prediction of their receptors in Hydra.Some neuropeptide families are conserved among Chordata and Arthropoda. This suggests that neuropeptides are conserved throughout animal evolution and that evolutionarily conserved neuropeptides may be identified in Hydra. Thus, I attempted to identify such neuropeptides in Hydra by in silico data mining.<br /> First, I developed an algorithm to detect possible neuropeptides in the Hydra EST database. I discovered a novel precursor gene that possibly encodes neuropeptide Y (NPY)-related peptides. The deduced precursor contained a N-terminal signal peptide, 3 putative NPY-related peptides, each flanked by an amidation motif "G(K/R)" at the Cterminal side. The sequence of C-terminal 5 amino acids in one of the deduced peptides was quite similar to neuropeptide F, a member of NPY family, of Helix aspersa (Brown garden snail). In situ hybridization revealed that the gene was expressed in a subpopulation of neurons distributed in tentacles and foot region of Hydra. Thus, the peptides were designated as Hydra neruropeptide Fs.<br /> Next, I looked for homologs of Hydra neuropeptides, Hym-355 and GLWamides in the Caenorhabditis elegans EST database as a midpoint between primitive and higher organisms. Genes that possibly encode Hym355-like and GLWamide-like peptides were found. The peptides similar to these C. elegans peptides were searched in the insect DNA databases. C.elegans Hym-355-like peptides showed similarity to insect PRXamides (Ecdysis triggering hormone, CAP, Pyrokinin), and C.elegans GLWamide-like peptides showed similarity to insect Allatostatin type B. These findings suggest that some of the neuropeptides are evolutionarily conserved throughout animal evolution.<br /> Neuropeptides and their receptors (GPCRs) evolve together. In fact, GPCRs form clusters in a phylogenetic tree and those in a cluster often use the same or similar ligands. In this study, sets of novel GPCR genes were identified from the Hydra whole genome shotgun database. Phylogenetic analysis showed that some of the Hydra GPCRs were highly related to neuropeptide receptors known in higher metazoans. One of them (HGR001) was related to neuropeptide Y and cholecystokinin receptors. The gene was expressed in dividing nematoblasts (sting cell precursors) suggesting its involvement in proliferation and/or early differentiation of nematocytes.<br /> These results suggest that some of the neuropeptides and their receptors are evolutionarily conserved and based on the conservation, novel peptides and GPCRs can be identified not only in Hydra but also in other animals.<br /><br />Chapter Ⅱ Identification of novel neuropeptide family, FRamide-1 and FRamide-2 In the course of systematic identification of peptide signaling molecules combined with EST database analysis in Hydra, we have identified a novel neuropeptide family that consists of two members with a C-terminal motif of FRamide; FRamide-1 (IPTGTLIFRamide) and FRamide-2 (APGSLLFRamide). The precursor sequence deduced from cDNA contained a single copy each of FRamide-1 and FRamide-2 precursor. The expression analysis by whole-mount in situ hybridization showed that the peptide encoding gene was specifically expressed in a subpopulation of neurons that were distributed throughout the body from tentacles to basal disc. In order to analyze the subpopulation of FRamide-1 and FRamide-2 expressing neuron in Hydra, the expression pattern was compared with other neuropeptides (Hym-176, Hym-355, GLWamides) expressing neurons. Double in situ hybridization analysis showed that the population was further subdivided into two; one consisted of neurons expressing both FRamide-1/FRamide-2 and Hym-176 encoding genes and the other consisted of neurons expressing only the FRamide-1/FRamide-2 encoding gene. The neuron population did not overlap with that expressing the Hym-355 or GLWamdie neuropeptide gene.<br /> FRamide-1 evoked elongation of the body column of epithelial Hydra that is composed of epithelial cells and gland cells but lacks essentially all the cells in the interstitial stem cell lineage including neurons. In contrast, FRamide-2 evoked the body column contraction. These results suggest that both of the neuropeptides directly act on epithelial (muscle) cells as neurotransmitters and are involved in the body movement in a longitudinal direction. | |||||
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| 値 | 有 | |||||
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| 内容記述タイプ | Other | |||||
| 内容記述 | application/pdf | |||||
