处于性腺不同发育阶段斜带石斑鱼垂体的EST表达差异分析
Differential Analysis of Expressed Sequence Tags from SMART cDNA Plasmid Libraries of the Orange-spotted Grouper (Epinephelus coioides) at Two Different Gonadal Development Stages
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摘要: 斜带石斑鱼是重要的海产经济鱼类，在其个体发育过程中存在先雌后雄的天然性反转现象。垂体是调节生长和生殖等生理过程的重要内分泌器官。构建了斜带石斑鱼分别处于卵巢发育起始和性反转后期的垂体SMART cDNA的质粒文库，并通过测序分别筛选到232个和258个表达序列标签(expressed sequence tags, EST)。将所得EST与GenBank数据库中的序列进行比对，结果表明，处于卵巢发育起始和性反转后期斜带石斑鱼垂体EST中，激素所占比例均为最高，分别为40.5%和34.9%。进一步比较分析了这两个性腺发育时期斜带石斑鱼垂体EST中各种激素相对表达丰度，表明生长/催乳激素家族（GH、PRL和SL）和阿黑皮素原（POMC）表达水平下降；促性腺激素α亚基（GTHα）表达水平急剧上升，促滤泡激素β亚基（FSHβ）、促黄体激素β亚基（LHβ）表达水平上升。Abstract: The orange-spotted grouper, Epinephelus coioides, is an important marine aquaculture fish and has been cultured in China and Southeast Asian countries. However, large-scale aquaculture of the grouper has been hindered by the rarity of natural males, because it is a protogynous hermaphroditic fish and sex inversion rarely occurs in captive stocks. In teleost fishes, the pituitary plays significant roles in many physiological functions, such as growth and reproduction. In this study, the SMART cDNA plasmid libraries of the pituitaries from orange-spotted groupers, at the early stage of ovary development and the late stage of sex inversion, were constructed. Two hundred and thirty-two and 258 ESTs were obtained from the two pituitary plasmid libraries respectively. Among the two groups of ESTs, the genes homologous to hormones were the most numerous in both groups, accounting for 40.5% and 34.9% of all ESTs respectively. Compared with the level of expression of hormones in the pituitary at the early stage of ovary development, the expression levels of growth hormone (GH), prolactin (PRL), somatolactin (SL) and proopiomelanocortin (POMC) were reduced, and the gonadotropin common α subunit (GTHα), folliclestimulating hormone β subunit (FSHβ) and luteinizing hormone β subunit (LHβ) were increased at the late stage of sex inversion.
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