Molecular cloning, characterization and expression analysis of ARMC6, ARMC7, ARMC8 from Pacific white shrimp, Litopenaeus vannamei

Armadillo repeat-containing proteins (ARMCs) comprise a large family that is widely distributed in eukaryotes and plays prominent roles in cell-cell adhesion, intracellular signaling, and cytoskeletal regulation. In this study, three ARMC genes, termed LvARMC6, LvARMC7 and LvARMC8, were identified and characterized from Litopenaeus vannamei. The complete cDNAs open reading frames (ORF) of LvARMC6, LvARMC7, and LvARMC8 (GenBank accession no. MG735126, MG728109 and KX058562) were 1410 bp, 570 bp and 2046 bp, encoding 469, 189, and 681 amino acids, respectively. Topology analysis indicated that three ARM domains were present in LvARMC6, one in LvARMC7 and six in LvARMC8. The identities of all the three LvARMCs with other species were between 50% and 71%. Phylogenetic analysis illustrated that different subtype of ARMCs formed their own separate branches and LvARMCs were placed in branch of invertebrates respectively with strong bootstrap support. The constitutive expressions of LvARMCs were confirmed by real-time quantitative PCR. LvARMC6, LvARMC7 and LvARMC8 were expressed highest in heart, gills and epithelium, respectively. After challenge with either white spot syndrome virus (WSSV), Vibrio parahemolyticus, or Staphylococcus aureus, all of the LvARMCs demonstrated differential expression profiles in hemocytes, hepatopancreas, intestine and gills. Taken together, our results suggest that LvARMCs may play a role in the innate immune defense against pathogenic viral and bacterial infections of L. vannamei.