Expression profiles of three crustin-like genes in Litopenaeus vannamei under Vibrio harveyi infection

Immune response of three crustin-like genes isolated from Litopenaeus vannamei under Vibrio harveyi infection was analyzed. Sequence analysis revealed that three crustin-like proteins contained whey acidic protein (WAP) domain, Crs 1 encoded 126 amino acids, Crs 2 encoded 156 amino acids, and Crs3 encoded 87 amino acids. Tissue expression pattern analysis showed that Crs 1 was not detected in the intestine, it was highest expressed in the muscle and lowest expressed in the hepatopancreas; Crs 2 was not detected in the hepatopancreas, intestine, and muscle but it was highest expressed in the hemocyte. Crs 3 was expressed in all tested tissues and was more abundant in the gill and muscle. Bacterial infection assay showed that mRNA level of Crs 1 in the gill was significantly upregulated at 24 h and 7 days; it was upregulated at 7 days in the muscle. The transcript level of Crs 2 in the hemocyte was upregulated at 24 h and significantly downregulated at 7 days, and it was downregulated in the heart at 24 h and 7 days. mRNA levels of Crs 3 in the hemocyte and hepatopancreas were significantly increased at 24 h; it was upregulated at 7 days in the heart and muscle. The results indicated that immune response of different crustins was tissue specific and the data provided us basic knowledge about the roles of three crustin-like genes in response to bacterial infection.