Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, PR China.
Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, PR China; Homey Group Co. Ltd, Rongcheng, 264306, PR China.
Fish Shellfish Immunol. 2019 Jun;89:271-280. doi: 10.1016/j.fsi.2019.03.074. Epub 2019 Mar 30.
Lysin motif (LysM) is involved in chitin, peptidoglycan and other structurally-related oligosaccharides recognition and binding, and it is important for the biological processes of responsing to bacterial and viral infections and pathogen defense. LysM is also a widely spread protein, ranging from prokaryotes to eukaryotes, including bacteria, plants and mammals. However, research of LysM in teleosts especially in marine fish was rarely scarce. In the present study, four novel LysM domain-containing proteins in turbot (Scophthalmus maximus), named as SmLysMd1, SmLysMd2, SmLysMd3, and SmLysMd4, were cloned and identified firstly. The full-length cDNA of SmLysMd1 was 1235 bp with a 678 bp ORF, capable of encoding a peptide of 225 amino acids. The complete cDNA sequence of SmLysMd2 was 1273 bp, and contained a 675 bp ORF, encoding a predicted protein of 224 amino acids. The full-length of SmLysMd3 cDNA was 2132 bp, containing a ORF of 987 bp, with a ORF of encoding 328 amino acids. The full-length SmLysMd4 cDNA was 1115 bp contained a 888 bp ORF, encoding 295 amino acids. And all the four predicated proteins contained a specific LYSM domain. Moreover, SmLysMd1 and SmLysMd2 belong to the intracellular non-secretory types, and SmLysMd3 and SmLysMd4 belong to the anchored transmembrane types. In addition, the four SmLysMd were ubiquitously expressed in all the examined tissues. Moreover, the SmLysMds levels were up-regulated in muscle and liver, and had a reduce tendency immediately in different degree following Vibrio vulnificus challenge, indicating that the turbot LysM could be participant in the immune responses to bacterial infections. The present result of LysM in turbot for the first time in a marine fish will provide foundation knowledge for the functions studies of LysM in immune responses. Further studies should be carried out to better understand their immune mechanism in turbot and other teleosts.
赖氨酰（LysM）基序参与几丁质、肽聚糖和其他结构相关寡糖的识别和结合，对于细菌和病毒感染及病原体防御的生物学过程至关重要。LysM 也是一种广泛分布的蛋白质，从原核生物到真核生物，包括细菌、植物和哺乳动物。然而，在硬骨鱼类中，特别是在海洋鱼类中，对 LysM 的研究很少。本研究首次克隆和鉴定了大菱鲆（Scophthalmus maximus）中的 4 种新型 LysM 结构域蛋白，分别命名为 SmLysMd1、SmLysMd2、SmLysMd3 和 SmLysMd4。SmLysMd1 的全长 cDNA 为 1235 bp，含有 678 bp 的 ORF，编码 225 个氨基酸的肽。SmLysMd2 的完整 cDNA 序列为 1273 bp，包含 675 bp 的 ORF，编码预测的 224 个氨基酸的蛋白质。SmLysMd3 cDNA 的全长为 2132 bp，含有 987 bp 的 ORF，编码 328 个氨基酸。SmLysMd4 cDNA 的全长为 1115 bp，含有 888 bp 的 ORF，编码 295 个氨基酸。这 4 种预测蛋白均含有特定的 LYSM 结构域。此外，SmLysMd1 和 SmLysMd2 属于细胞内非分泌型，SmLysMd3 和 SmLysMd4 属于锚定跨膜型。此外，这 4 种 SmLysMd 在所有检测组织中均广泛表达。此外，在肌肉和肝脏中 SmLysMds 水平上调，并且在不同程度上在 Vibrio vulnificus 攻毒后立即呈降低趋势，表明大菱鲆 LysM 可能参与细菌感染的免疫反应。本研究首次在海洋鱼类中对 LysM 进行了研究，为 LysM 在免疫反应中的功能研究提供了基础知识。应进一步开展研究，以更好地了解其在大菱鲆和其他硬骨鱼类中的免疫机制。
