Suppressor of cytokine signaling 2 (SOCS-2) homologue in disk abalone: Cloning, sequence characterization and expression analysis

Suppressor of cytokine signaling (SOCS) proteins are inhibitors of cytokine signaling pathways and key physiological regulators of both innate and adaptive immune systems in vertebrates.In present study, we provided the initial characterization of SOCS-2 homologue from the mollusk abalone Haliotis discus discus as a member of invertebrate SOCS-2. The disk abalone SOCS-2 cDNA (AbSOCS-2) contains 1700-bp full length with 771-bp coding sequence, which codes 257 amino acids protein. Based on the sequence analysis results, AbSOCS-2 showed characteristic SH2 domain and SOCS box similar to vertebrate SOCS counterparts. Additionally, 3′ UTR of the AbSOCS-2 contained two RNA instability motifs (ATTTA). Quantitative real-time PCR expression results showed that AbSOCS-2 was constitutively expressed in all examined tissues of healthy abalone showing tissue specific variation. AbSOCS-2 mRNA expression was induced significantly (p < 0.05) by bacteria mixture containing Vibrio alginolyticus, Vibrio parahemolyticus, and Listeria monocytogenes in abalone gill at 3 h post-induction (p.i.). Furthermore, AbSOC-2 mRNA was significantly (p < 0.05) induced by viral haemorrhagic septicemia virus (VHSV) and lipopolysaccharide (LPS) treatments in abalone gill. Therefore, discovery and expression analysis of abalone SOCS-2 gene would provide evolutional relationship of SOCS family members and immune defense responses against bacteria, virus and LPS like immune modulators.