Biological functions of rhamnose-binding multiple lectins from fish eggs

本研究主要研究了从硬鱼卵中分离到的鼠李糖结合凝集素(RBLS)的分子结构、组织分布和生物学功能。为了比较和了解RBLS在鱼类中的分布和进化，对从鲑鱼(Oncorhynchus Keta)和白点鲑鱼(Salvelinus Leucomaenis)等其他鲑科鱼类中分离到的RBLS进行了鉴定。从石斑鱼卵中分离到3个RBL，分别命名为STL1、STL2和STL3，并对其进行了鉴定。这些亚基由三个(STL1)或两个(STL2和STL3)相同重复的碳水化合物识别结构域(CRD)组成。从鲑鱼卵中分离到3个RBL，分别命名为CSL1、CSL2和CSL3，并对其进行了鉴定。CSL由三个(对于CSL1)或两个(对于CSL2和CSL)随机重复的RBL CRD组成，其序列与STL相同。从白斑炭蛋中分离到两个RBL，命名为WCL1和WCL3。Wcl1和wcl3显示AP…分别与相应的STL1和STL3更接近90%的序列同源性，并且由三个(对于WCL1)或两个(对于WCL3)随机重复的RBL CRD组成。白斑炭中未检测到类STL2蛋白和mRNA。在此基础上，对RBLS及其CRD基序的分子进化进行了研究。CRD基序并不局限于鱼类，而是分布在其他各种动物中，可能是从一个共同的祖先基因进化而来的，在生物系统中发挥着自己的作用。本文研究了硬骨鱼胚胎发育过程中STLS蛋白和mRNAs的组织特异性定位及其变化。STL1的分布和表达谱不同于STL2和STL3。研究了细菌与STL的相互作用。STL是通过识别内毒素(LPS)和脂磷壁酸(LTA)来凝集细菌的，这两种物质分别是革兰氏阴性和革兰氏阳性细菌外膜的主要组成部分。这表明STL在生物防御系统中发挥着重要的作用。较少

This study focused on the molecular structure, tissue distribution, and biological function of rhamnosebinding lectins (RBLs) isolated from steelhead trout (Oncorhynchus mykiss) eggs. RBLs which were isolated from other Salmonidae such as chum salmon (Oncorhynchus keta) and white-spotted charr (Salvelinus leucomaenis) were characterized for comparison and to know the distribution and evolution of RBLs in fish. Three RBLs, named STL1, STL2, and STL3, were isolated from steelhead trout (Oncorhynchus mykiss) eggs and characterized. These subunits were composed of three (STL1) or two (for STL2 and STL3) tandemly repeated carbohydrate recognition domains (CRDs) in the sequences. Three RBLs named CSL1 CSL2 and CSL3, were isolated from chum salmon eggs and characterized. CSLs are composed of three (for CSL1) or two (for CSL2 and CSLS) tandemly repeated RBL CRDs in the sequences as same as STLs. Two RBLs, named WCL1 and WCL3, were isolated from white-spotted charr eggs. WCL1 and WCL3 showed ap … More proximately 90 % sequence identities to corresponding STL1 and STL3, respectively, and composed of three (for WCL1) or two (for WCL3) tandemly repeated RBL CRDs. STL2-like protein and mRNA were not detected in white-spotted charr. On the basis of the results obtained, the molecular evolution of RBLs and its CRD motif were examined. The CRD motif is not restricted to fishes but is distributed among various other animals, and may have evolved from a common ancestral gene to play their own roles in the biological system. The tissue-specific localization and the changes of STLs proteins and mRNAs during the embryonic development in the steelhead trout were investigated. STL1 has different distribution and expression profiles from those of STL2 and STL3. The interaction between bacteria and STLs was examined. STLs were demonstrated to agglutinate bacteria by recognizing lipopolysacchandes (LPS) and lipoteichoic acid (LTA), which are major integral components of the outer membranes of Gram-negative and Gram-positive bacteria, respectively. This indicates that STLs play important roles in biodefense system. Less