Yu Quanyou, Lu Cheng, Li Bin, Fang Shoumin, Zuo Weidong, Dai Fangyin, Zhang Ze, Xiang Zhonghuai
The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Southwest University, Chongqing, China.
Insect Biochem Mol Biol. 2008 Dec;38(12):1158-64. doi: 10.1016/j.ibmb.2008.08.002.
Glutathione S-transferases (GSTs) are a multifunctional supergene family and some play an important role in insecticide resistance. We have identified 23 putative cytosolic GSTs by searching the new assembly of the Bombyx mori genome sequence. Phylogenetic analyses on the amino acid sequences reveal that 21 of the B. mori GSTs fall into six classes represented in other insects, the other two being unclassified. The majority of the silkworm GSTs belong to the Delta, Epsilon, and Omega classes. Most members of each class are tandemly arranged in the genome, except for the Epsilon GSTs. Expressed sequence tags (ESTs) corresponding to 19 of the 23 GSTs were found in available databases. Furthermore RT-PCR experiments detected expression of all the GSTs in multiple tissues on day 3 of fifth instar larvae. Surprisingly, we found little or no expression of most Delta and Epsilon GSTs in the fat body, which is thought to be the main detoxification organ. This may explain the sensitivity of the silkworm to certain insecticides. Our data provide some insights into the evolution of the B. mori GST family and the functions of individual GST enzymes.
谷胱甘肽S-转移酶（GSTs）是一个多功能的超基因家族，其中一些在抗杀虫剂方面发挥着重要作用。通过搜索家蚕基因组序列的新组装结果，我们鉴定出了23个假定的胞质GSTs。对氨基酸序列的系统发育分析表明，家蚕的21个GSTs属于其他昆虫中存在的六个类别，另外两个未分类。家蚕的大多数GSTs属于Delta、Epsilon和Omega类别。除了Epsilon GSTs外，每个类别的大多数成员在基因组中都是串联排列的。在现有数据库中发现了与23个GSTs中的19个相对应的表达序列标签（ESTs）。此外，RT-PCR实验检测到五龄幼虫第三天时所有GSTs在多个组织中的表达。令人惊讶的是，我们发现大多数Delta和Epsilon GSTs在被认为是主要解毒器官的脂肪体中几乎没有或没有表达。这可能解释了家蚕对某些杀虫剂的敏感性。我们的数据为家蚕GST家族的进化以及各个GST酶的功能提供了一些见解。
