University of Maryland Center for Environmental Science, Institute of Marine and Environmental Technology, 701 East Pratt Street, Columbus Center, Suite 236, Baltimore, MD 21202, USA.
Fish Shellfish Immunol. 2012 Mar;32(3):469-75. doi: 10.1016/j.fsi.2011.11.013. Epub 2011 Dec 6.
The full-length cDNA encoding a putative lipoprotein receptor (CasLpR) was isolated from the hemocytes of Callinectes sapidus using 5' and 3' RACEs. The open reading frame for CasLpR contains a precursor of putative CasLpR consisting of 1710 amino acid residues including 22 amino acid residues of the signal peptide (22 amino acids). Mature CasLpR (1688 amino acids with 5.6% of phosphorylation sites) has multiple, putative functional domains: five low-density lipoprotein receptor domains in the N-terminus, and a G-protein-coupled receptor proteolysis site domain and a 7 transmembrane receptor (secretin family) domain in the C-terminus. To date, there are no proteins with a similar domain structure in the GenBank. The expression pattern of CasLpR was exclusive in hemocytes among all tested tissues obtained from a juvenile female at intermolt stage: brain, eyestalk ganglia, pericardial organs, and thoracic ganglia complex (nervous system); hepatopancreas (digestive system); heart, artery and hemocytes (circulatory system); gill and antennal gland (excretory system), hypodermis; and Y-organ (endocrine organ). There was no CasLpR expression in the ovary of an adult female. A putative function of CasLpR was examined after challenges of lipopolysaccharides (LPS) and lipoteichoic acid (LTA) in vivo using qRT-PCR assays. Animals at 24 h after injection of LPS or LTA up-regulated the expression of CasLpR in hemocytes by ∼3.5 and 1.4 folds, respectively, compared to the controls that received saline injection. LPS challenge also caused the greatest increment (∼55 folds) of heat shock protein 90 (Hsp90) expression in these samples. These data indicate that putative CasLpR and CasHsp90 may be involved in the defense system or the stress response of C. sapidus.
从中国对虾血淋巴细胞中用 5' 和 3' RACE 法克隆到一个假定的脂蛋白受体（CasLpR）的全长 cDNA。CasLpR 的开放阅读框包含一个由 1710 个氨基酸残基组成的假定 CasLpR 前体，其中包括 22 个氨基酸残基的信号肽（22 个氨基酸）。成熟的 CasLpR（含 5.6%磷酸化位点的 1688 个氨基酸）具有多个假定的功能域：N 端的 5 个低密度脂蛋白受体结构域，以及 C 端的 G 蛋白偶联受体蛋白水解位点结构域和 7 次跨膜受体（分泌素家族）结构域。到目前为止，GenBank 中没有具有类似结构域的蛋白质。CasLpR 的表达模式在蜕皮间期的未成年雌性个体的所有测试组织中均为血淋巴细胞所特有：脑、眼柄神经节、围心器和胸神经节复合体（神经系统）；肝胰腺（消化系统）；心脏、动脉和血淋巴细胞（循环系统）；鳃和触角腺（排泄系统）、真皮；和 Y 器官（内分泌器官）。成年雌性个体的卵巢中没有 CasLpR 表达。使用 qRT-PCR 检测体内脂多糖（LPS）和脂磷壁酸（LTA）的挑战后，检查了 CasLpR 的假定功能。与接受生理盐水注射的对照相比，注射 LPS 或 LTA 24 小时后的动物，血淋巴细胞中 CasLpR 的表达分别上调了约 3.5 倍和 1.4 倍。LPS 挑战还导致这些样本中热休克蛋白 90（Hsp90）的表达最大增加（约 55 倍）。这些数据表明，假定的 CasLpR 和 CasHsp90 可能参与中国对虾的防御系统或应激反应。
