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Title: | 胰島素樣生長因子結合蛋白在鯖鱂魚離子調控之角色 The role of insulin-like growth factor binding proteins in ion regulation of Indian medaka (Oryzias melastigma) |
Authors: | Yu-Hsin Tang 唐玉欣 |
Advisor: | 黃鵬鵬(Pung-Pung Hwang) |
Keyword: | 胰島素樣生長因子結合蛋白,離子調節,鈣離子恆定,離子細胞,上皮鈣離子通道,印度鯖鱂魚, Insulin-like growth factor binding protein,ion regulation,Ca2+ homeostasis,ionocyte,epithelial Ca2+ channel,Indian medaka, |
Publication Year : | 2020 |
Degree: | 碩士 |
Abstract: | 魚類鰓或胚胎表皮上的離子細胞是群負責滲透壓調節的特化細胞。目前已知胰島素 樣生長因子 (IGF) 可以調控離子運輸蛋白的表現及離子細胞型態,以適應高滲透壓的環 境。最近的研究發現,IGF 結合蛋白(IGFBP)家族中,斑馬魚 igfbp5a 在胚胎離子細胞中 對於鈣離子的恆定扮演重要的角色。大部分對於硬骨魚 IGFBP 家族的研究集中在面對 各種壓力下的生長反應,然而,很少去探究面對鹽度刺激的反應。因此,在本篇研究中, 我們利用廣鹽性魚類,印度鯖鱂魚做為調查 IGFBP 家族是否參與離子調控的模式動物。 在印度鯖鱂魚中,發現有 11 個 IGFBP 家族的基因。其中,10 型於鰓有表現(igfb1a, -1b, -2a, -2b, -3b, -4, -5a, -5b, -6a 和 -6b),但只有 igfbp5a 主要表現在鰓中。將成魚轉移到海 水後,大部分 igfbp 基因在鰓的表現量皆顯著下降。原位雜交及免疫組織化學染色的結 果顯示,igfbp5a 表現在標定離子細胞的鈉鉀離子幫浦蛋白質旁邊的較小細胞中。雙標記 原位雜交顯示出 igfbp5a 與上皮鈣離子通道(trpv6/ecac)表現位置相同,該通道是 ECaC 離子細胞的標誌,負責在淡水中吸收鈣離子。有趣的是,當胚胎適應在低鈣離子濃度環 境時,表達 igfbp5a 與 trpv6 的細胞數量顯著增加。另外,我們還發現,當阻斷 IGF 訊息 傳遞後,在低鈣環境下 trpv6 細胞數量的增加與鈣吸收的能力皆受到明顯的抑制。這些 實驗結果顯示,印度鯖鱂魚在低鈣環境時,可能通過 igfbp5a 參與 IGF 訊息傳遞的機制, 不但增加 trpv6 細胞的數量,同時也增加單細胞中鈣離子吸收的能力。 Ionocytes in fish gills and embryonic skin are specialized cells responsible for osmoregulation. Insulin-like growth factor (IGF) signaling has been known to regulate the expression of transporters and the morphology of ionocytes for hyperosmotic adaptation. Recently, one of IGF binding protein (IGFBP), igfbp5a, has been identified in embryonic ionocytes to play a role in calcium homeostasis in zebrafish. Studies on teleost IGFBPs were focused on how they mediate growth responses to stressors, while few studies investigated the responses after salinity challenge. In the present study, we aimed to investigate whether IGFBPs participate in ion regulation in a euryhaline species, Indian medaka (Oryzias melastigma). We found totally 11 IGFBP genes in Indian medaka. Among them, ten of IGFBP members (igfb1a, -1b, -2a, -2b, -3b, -4, -5a, -5b, -6a and -6b) are expressed in the gills, but only igfbp5a is dominantly expressed. Most of branchial igfbps expression were down-regulated after seawater exposure. In situ hybridization and immunocytochemistry showed that igfbp5a was expressed in the smaller adjacent cells next to Na+-K+-ATPase-labeled ionocytes. Besides, double-labeled ISH showed that the expression of igfbp5a was co-localize with the epithelial Ca2+ channel (trpv6/ecac) which is a marker of ECaC ionocyte for Ca2+ absorption in the freshwater. Interestingly, the number of igfbp5a and trpv6 expressing cells increased when acclimated to low [Ca2+] water. In addition, blockage of IGF signaling not only inhibits the increment of trpv6 expressing cells, but also impaired the ability of Ca2+ absorption of the ionocytes after low [Ca2+] acclimation. These results suggested, through igfbp5a, IGF signaling involved in the Ca2+ absorption mechanism by increase the Ca2+ uptake and trpv6 expressing cells under low [Ca2+] water in the Indian medaka. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/76475 |
DOI: | 10.6342/NTU202002011 |
Fulltext Rights: | 同意授權(全球公開) |
metadata.dc.date.embargo-lift: | 2023-07-29 |
Appears in Collections: | 漁業科學研究所 |
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U0001-2907202001200600.pdf | 4.81 MB | Adobe PDF | View/Open |
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