2009年2月,，中科院北京基因組研究所基因組科學(xué)及信息重點實驗室與華東師范大學(xué)生命科學(xué)學(xué)院合作的研究成果,，“Discovery of immune-related genes in Chinese mitten crab (Eriocheir sinensis) by expressed sequence tag analysis of haemocytes” 論文在Aquaculture雜志上發(fā)表。
甲殼動物養(yǎng)殖在全世界水產(chǎn)養(yǎng)殖業(yè)中占有極其重要的地位,，2004年,，在世界水產(chǎn)品生產(chǎn)總值中，甲殼動物總重量雖僅占6.19 %（約3.68 百萬噸）,，但總價值中卻占到了20.4 %（約1.44 百億美元）,。中華絨螯蟹俗稱河蟹，是中國著名的淡水蟹,，具有重要的經(jīng)濟價值,，從80年代以來河蟹養(yǎng)殖業(yè)發(fā)展迅速，已成為水產(chǎn)養(yǎng)殖支柱產(chǎn)業(yè)之一,。伴隨著養(yǎng)殖業(yè)的迅猛發(fā)展,，甲殼動物的病害也呈上升趨勢，在河蟹眾多病害中,，顫抖病是最為常見,、危害最為嚴重的一種。此暴發(fā)性疾病往往造成嚴重的經(jīng)濟損失,死亡率達70%以上,。它的病害防治,，至今仍是水產(chǎn)界面臨的難題之一。甲殼動物缺乏特異性的免疫系統(tǒng),，它們的免疫防御主要由細胞和體液免疫系統(tǒng)所組成,，通過血細胞或淋巴細胞的吞噬、包囊作用排除異己的微生物和病原體,?？咕?antimicrobial peptide,，AMP)作為其中一種免疫因子在生物中廣泛存在，它是在外界條件刺激下,，生物免疫防御系統(tǒng)產(chǎn)生的一類對抗外源性病原體致病作用的具有免疫活性的多肽物質(zhì),，是脊椎動物、無脊椎動物和植物先天性免疫的關(guān)鍵因子,。而在淡水種類如中華絨螯蟹中還未見相關(guān)報道,。為了充分鑒定河蟹的免疫相關(guān)的基因，發(fā)現(xiàn)潛在的抗菌肽,，提高蟹體自身免疫能力,，我們與華東師范大學(xué)合作，以其血液為材料,，利用EST分析的手段對其轉(zhuǎn)錄組進行了研究,。
本次科研人員對樣品隨機測序（5’端）3118條，一共得到3041條高質(zhì)量的EST序列,，并最終得到1039條unigene（319條contig和720條singleton）,。通過與公共數(shù)據(jù)庫內(nèi)的序列進行比對，總共注釋了488（47%）個基因,。通過基因表達豐度和功能分析（主要是GO和KAAS）,，對其基因表達譜特征有了全面的認識。其中與免疫相關(guān)的基因共鑒定到26個基因,，根據(jù)其功能主要分為五類抗菌肽,、酚氧化酶系統(tǒng)、超氧化物歧化酶系統(tǒng),、凝結(jié)系統(tǒng)和模式識別分子,。主要的免疫因子為Kazal-type proteinase inhibitor和the C-type lectin，我們還鑒定到三種潛在的抗菌肽分子,，為之后克隆其全長基因序列并研究功能奠定了基礎(chǔ)。（生物谷Bioon.com）
生物谷推薦原始出處：
Aquaculture doi:10.1016/j.aquaculture.2008.10.050
Discovery of immune-related genes in Chinese mitten crab (Eriocheir sinensis) by expressed sequence tag analysis of haemocytes
Daxian Zhaoa, 1, Shuhui Songb, c, 1, Qun Wanga, Xiaowei Zhangb, Songnian Hub and Liqiao Chena, ,
aDepartment of Biology, East China Normal University, Shanghai 200062, PR China
bKey Laboratory of Genome Science and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, PR China
cGraduated University of the Chinese Academy of Sciences, Beijing 100094, PR China
Abstract
To identify distinctive genes associated with immunity in the Chinese mitten crab (Eriocheir sinensis), an expressed sequence tag (EST) library was constructed from haemocytes of this economically important species. 3118 clones were unidirectionally sequenced and analyzed by homology searches against sequences in the GenBank, KEGG and Uniprot. Significant homology (BLASTX, e-values < 10? 5) to known genes was found in 488 of the 1039 unique sequences. The automatic functional classification based on KEGG and Gene Ontology revealed 26 putative immune-related genes (2.5% of all unique sequences, 18.9% of all ESTs). These 26 genes coded for enzymes and proteins in the clotting and prophenoloxidase-activating system, antioxidative enzymes, antimicrobial peptides, and pattern recognition molecules. The existence of these molecular processes in the activation of cellular defense in crab has not been previously reported. According to EST abundance, the major immune-related genes were the Kazal-type proteinase inhibitor (337, 11.1% of all ESTs) and the C-type lectin (72, 2.4%). The EST sequences of mitten crab haemocytes provide important information for understanding the evolution of the immune system among crustaceans in general. This study lays the groundwork for development of molecular markers related to disease resistance in the crab.
