Abstract:  Annexins (ANX) are a multigene family of Ca2+-dependent phospholipid binding proteins, which are involved in the processes, such as membrane repair, ion channel regulation, signal transduction, vesicular transport and cell proliferation. Some anxs are expressed in the growth and environment (thermal and salinity)-dependent manner. In this study, bioinformatic approaches were used for sequence analysis of Neobenedenia melleni anxb1 (nmanxb1). And RT-qPCR was used to detect the mRNA expressions of nmanxb1 responding to the developmental and environmental changes. The results revealed that NmANXB1 was consist of 4 similar repeats made up of α helices, which contained 3 type II Ca2+ binding sites, 6 type III Ca2+ binding sites, and a KGD motif. Phylogenetic analysis of the amino acid sequences of some anxs showed that nmanxb1 grouped with other the parasitic helminth anxs belonging to group B. The results of RT-qPCR suggested that nmanxb1 mRNA was mainly expressed in the egg. Thermal stress (cold or hyperthermal stress) caused obviously increased nmanxb1 mRNA expressions in the egg, and hyperthermal and low salinity strss elevated significantly its expressions in the adult. It suggests that nmanxb1 may be involved in development and adaptation to adverse environmental conditions.

Key words: nmanxb1, sequence anlysis, gene expression, Neobenedenia melleni