马氏珠母贝(Pinctada fucata martensii)PmHEX基因的功能研究

几丁质是软体动物贝壳有机框架的重要成分,其代谢在贝壳矿化中发挥重要作用。β-N-乙酰-己糖胺酶(HEX, EC3.2.1.52)是几丁质代谢的关键水解酶。为了探究马氏珠母贝β-N-乙酰-己糖胺酶(Pm HEX)(登录号:MF555152)在贝壳形成中的作用,本研究利用原位杂交(ISH)技术检测Pm HEX基因在外套膜的定位,结果显示Pm HEX的mRNA主要分布于外侧褶的外上皮细胞、中褶的内侧上皮细胞和内褶上皮细胞。利用RNAi技术抑制Pm HEX表达后,Pm HEX在边缘区和套膜区的表达量均显著下调;SEM观察发现实验组的棱柱层和珍珠层的微观结构都出现不同程度的紊乱。综上所述,Pm HEX可能通过影响几丁质代谢,参与马氏珠母贝贝壳棱柱层和珍珠层的矿化过程。

Functional Study of PmHEX Gene in Pinctada fucata martensii

Chitin is an important component of mollusk shell organic frameworks and its metabolism is vital for shell mineralization. Beta-N-acetylhexosaminidase(HEX, EC3.2.1.52) is the key hydrolase of chitin metabolism.To investigate the function of beta-N-acetylhexosaminidase(Pm HEX)(GenBank: MF555152) in shell formation of P. f. martensii, this study detected the localization of Pm HEX in mantle by in situ hybridization technique(ISH).And the result showed that mRNA of Pm HEX was mainly distributed in the outer epidermal cells of the outer fold and the inner epithelial cells of the middle fold, as well as the epidermal cells of the inner fold. After inhibiting Pm HEX expression using RNAi technology, the expression of Pm HEX was significantly down regulated(p<0.05) in the marginal zone and pallial zone. Using SEM to observe the experimental group, it indicated that the microstructure of both prismatic layer and nacreous layer crystallized showed different degrees of disorder. All in all, these results indicated that Pm HEX might participate in the mineralization process of prismatic layer and nacreous layer of Pinctada fucata martensii through affecting chitin metabolism.