Biotechnology Research Division, National Fisheries Research and Development Institute, 408-1, Sirang-ri, Gijang-eup, Gijang-gun, Busan 619-902, Republic of Korea.
Fish Shellfish Immunol. 2011 Dec;31(6):1201-7. doi: 10.1016/j.fsi.2011.10.024. Epub 2011 Oct 30.
A fish-egg lectin, RbFEL, was identified from rock bream (Oplegnathus fasciatus) and its expression analysed. In both vertebrates and invertebrates, carbohydrate-binding proteins (lectins) play an important role in innate immunity against microbial invasion. Here, we report the cloning of a fish-egg lectin from rock bream using a combination of expression sequence tag (EST) analyses. The full-length cDNA of RbFEL is composed of 1512-bp with a 780-bp ORF that encodes 259 amino acid residues. The deduced polypeptide exhibits six conserved residues of the FEL family. All cysteine positions in each domain were completely conserved. Reverse transcription quantitative real-time PCR analysis of the tissues revealed that RbFEL mRNA was abundantly expressed in liver, moderately expressed in head kidney and rarely expressed in other tissues. Expression analyses of time series sampled fertilised eggs showed that expression gradually increased 1, 3, 12, 24 and 36 h after fertilisation. In addition, RbFEL expression was significantly up-regulated in rock bream challenged with Edwardsiella tarda, Streptococcus iniae and red sea bream iridovirus (RSIV). These results suggest that RbFEL is a member of the egg-lectin family and is involved in the innate immune response in rock bream.
从石斑鱼（Oplegnathus fasciatus）中鉴定出一种鱼卵凝集素 RbFEL，并分析了其表达情况。在脊椎动物和无脊椎动物中，糖结合蛋白（凝集素）在先天免疫抵抗微生物入侵中起着重要作用。在这里，我们使用表达序列标签（EST）分析报告了从石斑鱼中克隆鱼卵凝集素的情况。RbFEL 的全长 cDNA 由 1512-bp 组成，其中包含 780-bp 的 ORF，编码 259 个氨基酸残基。推断的多肽表现出 FEL 家族的六个保守残基。每个结构域中的所有半胱氨酸位置均完全保守。对组织进行的反转录定量实时 PCR 分析表明，RbFEL mRNA 在肝脏中大量表达，在头肾中中度表达，在其他组织中很少表达。对受精后不同时间点采集的受精卵进行表达分析表明，表达水平在受精后 1、3、12、24 和 36 小时逐渐增加。此外，RbFEL 的表达在受到迟钝爱德华氏菌、链球菌和红鳍东方鲀虹彩病毒（RSIV）挑战的石斑鱼中显著上调。这些结果表明，RbFEL 是卵凝集素家族的成员，参与石斑鱼的先天免疫反应。
