Kakani_2008_Insect.Biochem.Mol.Biol_38_781

Reference

Title : A small deletion in the olive fly acetylcholinesterase gene associated with high levels of organophosphate resistance - Kakani_2008_Insect.Biochem.Mol.Biol_38_781
Author(s) : Kakani EG , Ioannides IM , Margaritopoulos JT , Seraphides NA , Skouras PJ , Tsitsipis JA , Mathiopoulos KD
Ref : Insect Biochemistry & Molecular Biology , 38 :781 , 2008
Abstract : Organophosphate resistance in the olive fly was previously shown to associate with two point mutations in the ace gene. The frequency of these mutations was monitored in Bactrocera oleae individuals of increasing resistance. In spite of the difference in resistance among the individuals, there was no correlation between mutation frequencies and resistance level, indicating that other factors may contribute to this variation. The search for additional mutations in the ace gene of highly resistant insects revealed a small deletion at the carboxyl terminal of the protein (termed Delta3Q). Significant correlation was shown between the mutation frequency and resistance level in natural populations. In addition, remaining activity of acetylcholinesterase enzyme (AChE) after dimethoate inhibition was higher in genotypes carrying the mutation. These results strongly suggest a role of Delta3Q in high levels of organophosphate (OP) resistance. Interestingly, the carboxyl terminal of AChE is normally cleaved and substituted by a glycosylphosphatidylinositol (GPI) anchor. We hypothesize that Delta3Q may improve GPI anchoring, thus increasing the amount of AChE that reaches the synaptic cleft. In this way, despite the presence of insecticide, enough enzyme would remain in the cleft for its normal role of acetylcholine hydrolysis, allowing the insect to survive. This provides a previously un-described mechanism of resistance.
ESTHER : Kakani_2008_Insect.Biochem.Mol.Biol_38_781
PubMedSearch : Kakani_2008_Insect.Biochem.Mol.Biol_38_781
PubMedID: 18625401

Related information

Citations formats

Kakani EG, Ioannides IM, Margaritopoulos JT, Seraphides NA, Skouras PJ, Tsitsipis JA, Mathiopoulos KD (2008)
A small deletion in the olive fly acetylcholinesterase gene associated with high levels of organophosphate resistance
Insect Biochemistry & Molecular Biology 38 :781

Kakani EG, Ioannides IM, Margaritopoulos JT, Seraphides NA, Skouras PJ, Tsitsipis JA, Mathiopoulos KD (2008)
Insect Biochemistry & Molecular Biology 38 :781

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    [paper] => Kakani_2008_Insect.Biochem.Mol.Biol_38_781
    [author] => Kakani EG || Ioannides IM || Margaritopoulos JT || Seraphides NA || Skouras PJ || Tsitsipis JA || Mathiopoulos KD
    [year] => 2008
    [title] => A small deletion in the olive fly acetylcholinesterase gene associated with high levels of organophosphate resistance
    [journal] => Insect Biochemistry & Molecular Biology
    [volume] => 38
    [page] => 781
    [medline] => 18625401
    [abstract] => Kakani_2008_Insect.Biochem.Mol.Biol_38_781
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            [longtext] => Kakani_2008_Insect.Biochem.Mol.Biol_38_781
            [content] => Organophosphate resistance in the olive fly was previously shown to associate with two point mutations in the ace gene. The frequency of these mutations was monitored in Bactrocera oleae individuals of increasing resistance. In spite of the difference in resistance among the individuals, there was no correlation between mutation frequencies and resistance level, indicating that other factors may contribute to this variation. The search for additional mutations in the ace gene of highly resistant insects revealed a small deletion at the carboxyl terminal of the protein (termed Delta3Q). Significant correlation was shown between the mutation frequency and resistance level in natural populations. In addition, remaining activity of acetylcholinesterase enzyme (AChE) after dimethoate inhibition was higher in genotypes carrying the mutation. These results strongly suggest a role of Delta3Q in high levels of organophosphate (OP) resistance. Interestingly, the carboxyl terminal of AChE is normally cleaved and substituted by a glycosylphosphatidylinositol (GPI) anchor. We hypothesize that Delta3Q may improve GPI anchoring, thus increasing the amount of AChE that reaches the synaptic cleft. In this way, despite the presence of insecticide, enough enzyme would remain in the cleft for its normal role of acetylcholine hydrolysis, allowing the insect to survive. This provides a previously un-described mechanism of resistance.
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