Previous studies have shown that ribosomal proteins play important roles in ribosome assembly and protein translation, but other biological functions remain ill-defined. Here it is clearly demonstrated that RPS18 is a newly identified PGN-binding protein which is present abundantly in the eggs/embryos of zebrafish. Recombinant RPS18 not only identifies the bacterial signature molecule PGN, LPS, and LTA, and binds the bacteria as a pattern recognition receptor, but also kills the Gram-positive and Gram-negative bacteria as an antibacterial effector molecule. What is important is that, we reveal that microinjection of rRPS18 into early embryos significantly improved the resistance of the embryos against pathogenic Aeromonas hydrophila challenge, and co-injection of anti-RPS18 antibody could markedly reduced this improved bacterial resistance. In summary, these results indicate that RPS18 is a maternal immune factor that can protect the early embryos of zebrafish against pathogenic attacks. This work also provides another angle for understanding the biological functions of ribosomal proteins.

先前的研究表明，核糖体蛋白在核糖体组装和蛋白质翻译中起重要作用，但其他生物学功能仍然不明确。这里清楚地表明 RPS18 是一种新发现的 PGN 结合蛋白，它大量存在于斑马鱼的卵/胚胎中。重组RPS18不仅识别细菌特征分子PGN、LPS和LTA，并作为模式识别受体结合细菌，而且作为抗菌效应分子杀死革兰氏阳性菌和革兰氏阴性菌。重要的是，我们揭示了将 rRPS18 显微注射到早期胚胎中显着提高了胚胎对致病性嗜水气单胞菌的抵抗力挑战，并且共同注射抗 RPS18 抗体可以显着降低这种改善的细菌耐药性。总之，这些结果表明RPS18是一种母体免疫因子，可以保护斑马鱼的早期胚胎免受病原侵袭。这项工作还为理解核糖体蛋白的生物学功能提供了另一个角度。