Identification and expression analysis of two splice variants of the 14-3-3 epsilon from Litopenaeus Vannamei during WSSV infections

The 14-3-3 epsilon (14-3-3 epsilon) is a member of the 14-3-3-protein family claimed to play important roles in many biological processes. In this study, two alternative 14-3-3 epsilon mRNAs, designated as 14-3-3EL and 14-3-3ES were identified from the shrimp L. vannamei. The 14-3-3EL isoform contains an insertion of 48 nucleotides by intron retention in the pre-mRNA of 14-3-3 epsilon. While the 14-3-3ES occurred after being fully spliced. Using the yeast two hybrid method, the pattern of dimer formation by the two alternative 14-3-3 epsilon isoforms revealed that the shrimp 14-3-3 epsilon formed both homodimers and heterodimers. Both 14-3-3 epsilon transcript variants were constitutively expressed in all shrimp tissues tested but the level of the 14-3-3ES isoform was always lower. However, after white spot syndrome virus (WSSV) infection, the expression level of the two transcript variants changed. At 48 h after infection, expression of 14-3-3EL mRNA increased significantly in the gill and muscle tissue whereas the expression 14-3-3ES increased only in muscle. It was of interest that in the lymphoid organ, there was a significant down-expression of both transcript variants. From these results we suggest that 14-3-3EL and 14-3-3ES might be related to different cellular processes that are modulated during virus infection.