A homologue of dermatopontin from Haliotis diversicolor and its response to pathogenic infection

Dermatopontin (DPT), a component of the extracellular matrix, plays important roles in cell‐matrix interactions and matrix assembly. Some studies have revealed that it has more general functions in biological activities. However, its function in molluscs is poorly understood. In this study, a molluscan DPT gene, saDPT2, was cloned from small abalone Haliotis diversicolor. The full‐length cDNA of saDPT2 sequence is 620 bp, with a 531 bp open reading frame encoding a protein of 177 amino acids (aa). Amino acid sequence analysis revealed that saDPT2 shares conserved signature motifs with other DPT proteins, including three repeats of 10‐residue motif (S‐X‐H‐X‐N‐X‐Y‐E‐D‐R), which is similar to mammalian 6‐residue repeating sequence of D‐R‐E/Q‐W‐X‐F/Y. Quantitative real‐time PCR was employed to investigate the tissue distribution of saDPT2 mRNA, its expression at different developmental stages, and in abalone under bacteria challenge. The saDPT2 mRNA could be detected in all examined tissues and developmental stages. Moreover, the saDPT2 mRNA was up‐regulated in haemocytes and gills after bacteria injection. The results indicate that the saDPT2 could respond to pathogenic infection and may play a role in adult abalone immune system.