title: Identification, genomic organization and expression pattern of glutathione S-transferase in the silkworm, Bombyx mori.
abstract: 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.
authors.affiliation: The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Southwest University, Chongqing, China.
authors.forename: Quanyou
authors.initials: Q
authors.lastname: Yu
authors.forename: Cheng
authors.initials: C
authors.lastname: Lu
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Shoumin
authors.initials: S
authors.lastname: Fang
authors.forename: Weidong
authors.initials: W
authors.lastname: Zuo
authors.forename: Fangyin
authors.initials: F
authors.lastname: Dai
authors.forename: Ze
authors.initials: Z
authors.lastname: Zhang
authors.forename: Zhonghuai
authors.initials: Z
authors.lastname: Xiang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000201:enzymology / Q000235:genetics*; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D049750:Genome, Insect; D023281:Genomics; D005982:Glutathione Transferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D005982:Glutathione Transferase