2009年2月，中科院北京基因组研究所基因组科学及信息重点实验室与华东师范大学生命科学学院合作的研究成果，“Discovery of immune-related genes in Chinese mitten crab (Eriocheir sinensis) by expressed sequence tag analysis of haemocytes” 论文在Aquaculture杂志上发表。
甲壳动物养殖在全世界水产养殖业中占有极其重要的地位，2004年，在世界水产品生产总值中，甲壳动物总重量虽仅占6.19 %（约3.68 百万吨），但总价值中却占到了20.4 %（约1.44 百亿美元）。中华绒螯蟹俗称河蟹，是中国著名的淡水蟹，具有重要的经济价值，从80年代以来河蟹养殖业发展迅速，已成为水产养殖支柱产业之一。伴随着养殖业的迅猛发展，甲壳动物的病害也呈上升趋势，在河蟹众多病害中，颤抖病是最为常见、危害最为严重的一种。此暴发性疾病往往造成严重的经济损失,死亡率达70%以上。它的病害防治，至今仍是水产界面临的难题之一。甲壳动物缺乏特异性的免疫系统，它们的免疫防御主要由细胞和体液免疫系统所组成，通过血细胞或淋巴细胞的吞噬、包囊作用排除异己的微生物和病原体。抗菌肽(antimicrobial peptide，AMP)作为其中一种免疫因子在生物中广泛存在，它是在外界条件刺激下，生物免疫防御系统产生的一类对抗外源性病原体致病作用的具有免疫活性的多肽物质，是脊椎动物、无脊椎动物和植物先天性免疫的关键因子。而在淡水种类如中华绒螯蟹中还未见相关报道。为了充分鉴定河蟹的免疫相关的基因，发现潜在的抗菌肽，提高蟹体自身免疫能力，我们与华东师范大学合作，以其血液为材料，利用EST分析的手段对其转录组进行了研究。
本次科研人员对样品随机测序（5’端）3118条，一共得到3041条高质量的EST序列，并最终得到1039条unigene（319条contig和720条singleton）。通过与公共数据库内的序列进行比对，总共注释了488（47%）个基因。通过基因表达丰度和功能分析（主要是GO和KAAS），对其基因表达谱特征有了全面的认识。其中与免疫相关的基因共鉴定到26个基因，根据其功能主要分为五类抗菌肽、酚氧化酶系统、超氧化物歧化酶系统、凝结系统和模式识别分子。主要的免疫因子为Kazal-type proteinase inhibitor和the C-type lectin，我们还鉴定到三种潜在的抗菌肽分子，为之后克隆其全长基因序列并研究功能奠定了基础。（生物谷Bioon.com）
生物谷推荐原始出处：
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.
