Key Laboratory of Protection and Utilization of Aquatic Germplasm Resource, Ministry of Agriculture and Rural Affairs, Liaoning Key Laboratory of Germplasm Improvement and Fine Seed Breeding of Marine Aquatic Animals, Liaoning Ocean and Fisheries Science Research Institute, Dalian, Liaoning, PR China.
Key Laboratory of Protection and Utilization of Aquatic Germplasm Resource, Ministry of Agriculture and Rural Affairs, Liaoning Key Laboratory of Germplasm Improvement and Fine Seed Breeding of Marine Aquatic Animals, Liaoning Ocean and Fisheries Science Research Institute, Dalian, Liaoning, PR China.
Fish Shellfish Immunol. 2024 Jan;144:109263. doi: 10.1016/j.fsi.2023.109263. Epub 2023 Nov 30.
Pattern recognition receptors (PRRs) are the first line of immune defense in invertebrates against pathogen infection; they recognize pathogens and transmit signals to downstream immune pathways. Among these, peptidoglycan recognition proteins (PGRPs) are an important family in invertebrates that generally comprise of complicated isoforms. A comprehensive understanding of PGRPs in evolutionarily and economically important marine invertebrates, such as the sea cucumber, Apostichopus japonicus, is crucial. Previous studies have identified two PGRPs in sea cucumber, AjPGRP-S and AjPGRP-S1, and another novel short-type PGRP, AjPGRP-S3, was additionally identified here. The full-length cDNA sequence of AjPGRP-S3 was obtained here by PCR-RACE, followed by which showed its gene expression analyses by in situ hybridization that showed it to be relatively highly expressed in coelomocytes and tube feet. Based on an analysis of the recombinant protein, rAjPGRP-S3, a board-spectrum pathogen recognition ability was noted that covered diverse Gram-negative and -positive bacteria, and fungi. Moreover, according to the results of yeast two-hybridization, it was suggested that rAJPGRP-S3 interacted with multiple immune-related factors, including proteins involved in the complement system, extracellular matrix, vesicle trafficking, and antioxidant system. These findings prove the important functions of AjPGRP-S3 in the transduction of pathogen signals to downstream immune effectors and help explore the functional differences in the AjPGRP isoforms.
模式识别受体（PRRs）是无脊椎动物抵御病原体感染的第一道免疫防线；它们识别病原体并将信号传递到下游免疫途径。在这些途径中，肽聚糖识别蛋白（PGRPs）是无脊椎动物中一个重要的家族，通常包括复杂的同工型。全面了解在进化和经济上重要的海洋无脊椎动物（如海参）中的 PGRPs 至关重要。以前的研究已经在海参中鉴定出两种 PGRPs，即 AjPGRP-S 和 AjPGRP-S1，这里还另外鉴定出了一种新型短型 PGRP，即 AjPGRP-S3。通过 PCR-RACE 获得了 AjPGRP-S3 的全长 cDNA 序列，随后通过原位杂交进行了基因表达分析，结果显示其在体腔细胞和管足中相对高表达。基于对重组蛋白 rAjPGRP-S3 的分析，发现其具有广谱的病原体识别能力，涵盖了多种革兰氏阴性和阳性细菌以及真菌。此外，根据酵母双杂交的结果，表明 rAJPGRP-S3 与多种免疫相关因子相互作用，包括补体系统、细胞外基质、囊泡运输和抗氧化系统中的蛋白质。这些发现证明了 AjPGRP-S3 在病原体信号转导到下游免疫效应物中的重要功能，并有助于探索 AjPGRP 同工型的功能差异。
