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Characterization of the promoters of Epsilon glutathione transferases in the mosquito Anopheles gambiae and their response to oxidative stress

Ding, Y. C., Hawkes, Nicola J., Meredith, J., Eggleston, P., Hemingway, Janet ORCID: and Ranson, Hilary ORCID: (2005) 'Characterization of the promoters of Epsilon glutathione transferases in the mosquito Anopheles gambiae and their response to oxidative stress'. Biochemical Journal, Vol 387, pp. 879-888.

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Epsilon class GSTs (gluntathione transferases) are expressed at higher levels in Anopheles gambiae mosquitoes that are resistant to DDT [1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane] than in insecticide-susceptible individuals. At least one of the eight Epsilon GSTs in this species, GSTe2, efficiently metabolizes DDT to DDE [1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane]. In the present study, we investigated the factors regulating expression of this class of GSTs. The activity of the promoter regions of GSTe2 and GSTe3 were compared between resistant and susceptible strains by transfecting recombinant reporter constructs into an A. gambiae cell line. The GSTe2 promoter from the resistant strain exhibited 2.8-fold higher activity than that of the susceptible strain. Six polymorphic sites were identified in the 352 bp sequence immediately upstream of GSTe2. Among these, a 2 bp adenosine indel (insertion/deletion) was found to have the greatest effect on determining promoter activity. The activity of the GSTe3 promoter was elevated to a lesser degree in the DDT-resistant strain (1.3-fold). The role of putative transcription-factor-binding sites in controlling promoter activity was investigated by sequentially deleting the promoter constructs. Several putative transcription-factor-binding sites that are responsive to oxidative stress were present within the core promoters of these GSTs, hence the effect of H2O2 exposure on the transcription of the Epsilon GSTs was investigated. In the DDT-resistant strain, expression of GSTe1, GSTe2 and GSTe3 was significantly increased by a 1-h exposure to H2O2, whereas, in the susceptible strain, only GSTe3 expression responded to this treatment.

Item Type: Article
Uncontrolled Keywords: anopheles gambiae glutathione transferase (gst) insecticide resistance promoter 1,1, 1-trichloro-2,2-bis-(p-chlorophenyl)ethane(ddt) s-transferase drosophila-melanogaster insecticide-resistance gene-expression transcription cells defense element family ddt
Subjects: QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes
QX Parasitology > Insects. Other Parasites > QX 515 Anopheles
Faculty: Department: Groups (2002 - 2012) > Vector Group
Digital Object Identifer (DOI):
Depositing User: Sarah Lewis-Newton
Date Deposited: 07 Sep 2011 15:56
Last Modified: 30 Aug 2019 17:05


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