硬壳蛤MmDR2基因克隆及对溶藻弧菌的响应模式研究OA北大核心

This study investigated the molecular mechanisms by which the dopamine neuroendocrine system in Mercenaria mercenaria regulates the response to stress induced by Vibrio alginolyticus.We employed RACE tech-nology to clone the full-length cDNA sequence of the dopamine receptor 2(MmDR2)gene in the hard clam.Re-al-time quantitative PCR was employed to detect the expression patterns of MmDR2 in different tissues.Following a challenge with V.alginolyticus and dopamine stimulation,changes in the immune and antioxidant-related enzyme activity,as well as the expression of MmDR2,were measured at different time points.Results of the gene cloning revealed that MmDR2 is 1 464 bp in length,encoding 487 amino acids,and contains one DR2 core domain with a typical dopamine binding site.The multiple sequence alignment results showed that MmDR2 has high similarity with Dreissena polymorpha and Mya arenaria,at 79.69%and 75.10%,respectively.The phylogenetic tree results showed that MmDR2 and DR2 of D.polymorpha and M.arenaria clustered into one branch.The tissue distribution results demonstrated that the MmDR2 gene was expressed in all tissues,with higher expression levels in the gills,mantle,and hemocytes,and the lowest expression was found in the gonads.Under V.alginolyticus stress,the ex-pression of MmDR2 in hemocytes significantly increased,peaking at 6 h.V.alginolyticus infection of M.merce-naria significantly affected the immune and antioxidant-related enzyme activity in the digestive glands.Among these,the immune-related enzymes ACP,AKP,and LZM were initially activated and then gradually returned to normal levels,while the activities of antioxidant-related enzymes fluctuated;significant inhibition was revealed during the early stages of infection.However,when M.mercenaria was stimulated with dopamine and subsequently challenged with V.alginolyticus,the overall immune and antioxidant-related enzyme activities in their bodies were suppressed.These results indicate that MmDR2 plays an important biological role in the anti-infection immunity of M.mercenaria.