Miao Jingjing, Pan Luqing, Liu Na, Xu Chaoqun, Zhang Lin
The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, No. 5 Yushan Road, Qingdao 266003, China.
Mar Genomics. 2011 Jun;4(2):99-108. doi: 10.1016/j.margen.2011.03.002. Epub 2011 Apr 14.
Cytochrome P450 enzymes (CYP) and glutathione s-transferases (GST) are essential components of cellular detoxification systems. In this study we cloned full-length cDNAs encoding CYP4 and GSTpi homologues from scallop Chlamys farreri. Both sequences were deposited in the GenBank with accession no. ACL80141 for CYP4 and ACL80138 for GSTpi. The sequence called Cf (C. farreri) CYP4 is constituted by an ORF of 1317 bp encoding for a protein of 50.8 kDa. The CfGSTpi is constituted by an ORF of 618 bp encoding for a protein of 23.9 kDa. The comparison of the deduced amino acid sequences with CYP4 and GSTpi from vertebrates showed high conservation of the residues and domains essential to the function of these two enzymes. CfCYP4 and CfGSTpi mRNA expression was detected in digestive gland, gill, mantle, mature female gonad and adductor. We then utilized the real-time PCR to study expression levels of the CfCYP4 and CfGSTpi gene in response to exposure of Benzo[a]pyrene (BaP) (0.01 and 0.2 μg/L) for 10 days. The results showed that during the exposure to BaP, CfCYP4 was significantly decreased in the gill and digestive gland of scallops, and CfGSTpi was increased on day 3 until the end of exposure. The changes in CfGSTpi mRNA levels observed in scallops exposed to BaP indicated that GSTpi could play an important role in the detoxification of BaP.
细胞色素P450酶（CYP）和谷胱甘肽S-转移酶（GST）是细胞解毒系统的重要组成部分。在本研究中，我们从栉孔扇贝中克隆了编码CYP4和GSTpi同源物的全长cDNA。这两个序列已存入GenBank，登录号分别为CYP4的ACL80141和GSTpi的ACL80138。名为Cf（栉孔扇贝）CYP4的序列由一个1317 bp的开放阅读框组成，编码一个50.8 kDa的蛋白质。CfGSTpi由一个618 bp的开放阅读框组成，编码一个23.9 kDa的蛋白质。将推导的氨基酸序列与脊椎动物的CYP4和GSTpi进行比较，结果表明这两种酶功能所必需的残基和结构域具有高度保守性。在消化腺、鳃、外套膜、成熟雌性性腺和闭壳肌中检测到CfCYP4和CfGSTpi mRNA的表达。然后，我们利用实时PCR研究了CfCYP4和CfGSTpi基因在暴露于苯并[a]芘（BaP）（0.01和0.2 μg/L）10天后的表达水平。结果表明，在暴露于BaP期间，栉孔扇贝鳃和消化腺中的CfCYP4显著下降，而CfGSTpi在暴露第3天至结束时升高。在暴露于BaP的栉孔扇贝中观察到的CfGSTpi mRNA水平变化表明，GSTpi可能在BaP的解毒中发挥重要作用。
