Characterization and function of a β-catenin homolog from Litopenaeus vannamei in WSSV infection

As a conserved signaling pathway, Wnt/β-catenin signaling pathway participates in many physiological activities, including cell differentiation, apoptosis and so on. β-catenin is the key molecule of Wnt/β-catenin signaling pathway and plays a pivotal role. In this article, a β-catenin homolog from Litopenaeus vannamei (designed as Lv-β-catenin) was cloned and its role in WSSV infection was investigated. Sequence analysis suggested that Lv-β-catenin had characters of β-catenin family. Semi-quantitative RT-PCR showed that Lv-β-catenin transcripted in all detected tissues. In the subsequent WSSV infection experiments, it was found that the transcription levels of Lv-β-catenin were down-regulated, as well as the expression levels. Immunofluorescence assay further confirmed that WSSV could reduce the amount of Lv-β-catenin and promoted Lv-β-catenin to translocate into the nucleus. Moreover, we found that WSSV could influence the amount of Lv-β-catenin by ubiquitination. While Lv-β-catenin was up-regulated by a β-catenin activator GSK-3 Inhibitor IX, the transcription of virus immediate early gene WSSV069 was significantly inhibited. In addition, it was found that Lv-β-catenin could interact with WSSV069. Conclusively, our study provided evidences that β-catenin may participate in the WSSV infection, and Wnt/β-catenin signal pathway may play an important role in immune regulation.