Preliminary study of the intranuclear function of Sma and Mad related protein 5 gene in Litopenaeus vannamei.

Litopenaeus vannamei Smad5 (LvSmad5) in cytoplasm has been proved to be involved in environmental stress response. As LvSmad5 could also locate in nucleus under specific stress, it was conjectured that LvSmad5 might participate in environmental stress response. While, the experimental evidence is still lacking. In this study, cytosolic LvSmad5 mutant or nuclear LvSmad5 mutant was expressed in Drosophila S2 cells, and then transcriptomic analysis of mentioned cells was performed using Illumina HiSeq based RNA-Seq, to reveal the function of LvSmad5 in nucleus. By comparing the two groups of cDNA libraries from S2 cells with cytosolic or nucleus LvSmad5 mutant, 86 differentially expressed genes as well as 765 differentially expressed transcripts were found. It was revealed that genes in the ER-stress response pathway, such as unfolded protein response and ER-associated degradation (ERAD) were enriched. Additionally, some kinds of metabolic reprogramming occurred in S2 cells with over-expressing nuclear LvSmad5, for significant changes in the expression of some metabolism-related genes. To test our infer that nuclear LvSmad5 was engaged in environmental stress response, homologous gene of Drosophila translocation in renal carcinoma on chromosome 8 in L.vannamei (LvTRC8) was chosen for further investigation. And studies about LvTRC8, a member of ERAD showed that it was induced by ER-stress or heat shock treatment. Suppressed the expression of LvTRC8 increased the cumulative mortality of shrimp upon stress. In some degree, these results support our speculation that nuclear LvSmad5 are involved in the environmental stress response of L. vannamei in fact.

Transcriptome analysis endoplasmic reticulum-stress response in Litopenaeus vannamei hemocytes.

Numerous studies have proved that endoplasmic reticulum (ER)-stress is an important cause of aquatic animal diseases. Therefore, for effectively preventing and controlling aquatic animal diseases, a systematic and in-depth understanding of the environmental stress response in aquatic animals is necessary. In present study, the influence of ER-stress in Litopenaeus vannamei was investigated using Illumina HiSeq based RNA-Seq. Comparing to the cDNA library of hemocytes treated with DMSO in L. vannamei, 286 unigenes were significantly upregulated and 473 unigenes were significantly down-regulated in the Thapsigargin treated group. KEGG analysis indicated that the differentially expressed genes (DEGs) are mainly related to ER-stress, immune as well as metabolism. Besides the classical ER-stress response pathways, the regulation of cell cycle and DNA replication are also important measures of ER-stress response. It has been suggested that the influence of ER-stress on immune genes might be an important factor in environmental stress inducing shrimp disease. Our investigation exhibited that immune-related DEG Prophenoloxidase activating enzyme 2 (LvPPAE2) roled in anti-pathogen immunity of shrimp. This study provides a solid foundation for uncovering the environmental adaptation response and especially its relationship with L. vannamei immune system.

A IFI27 gene contributes to ER-stress mediated apoptosis and benefits for white spot syndrome virus infection in Litopenaeus vannamei.

The interplay between virus and host has been one of the hot spot in virology, and it is also the important aspect of revealing the mechanism of virus infection. Increasing studies revealed that several key molecules took part in the process of virus-host interaction. White spot syndrome virus (WSSV) has been proved to affect several physiological processes of the host cells, especially apoptosis. While the relationship between them still remains unclear. In this study, a IFI27 gene (LvIFI27) of Litopenaeus vannamei was cloned. It is indicated that LvIFI27 was induced upon endoplasmic reticulum (ER)-stress and unfolded protein response activator Thapsigargin. Unlike human IFI27 locating to mitochondria, LvIFI27 lied to ER, and was involved in cell apoptosis process. Moreover, results of cumulative mortality analysis showed that LvIFI27 might contributed to WSSV proliferation by promoting apoptosis during the process of viral infection. Findings in this study enriched our understanding of the relationship between WSSV infection and ER-stress mediated apoptosis.