Possible involvement of the long terminal repeat of transposable element 17.6 in regulating expression of an insecticide resistance-associated P450 gene in Drosophila.
P450-A and P450-B are electrophoretically defined subsets of cytochrome P450 enzymes in Drosophila melanogaster. P450-A is present among all strains tested, whereas expression of P450-B is associated with resistance to insecticides. Monoclonal antibodies were used to obtain cDNA clones for an enzyme from each P450 subset (i.e., P450-A1 and P450-B1). The P450-B1 cDNA was sequenced and shown to code for a P450 of 507 amino acids. Its gene has been named CYP6A2. Comparative molecular analyses of a pair of susceptible, 91-C, and resistant, 91-R, Drosophila strains were made. There was 20-30 times more P450-B1 mRNA in 91-R than in 91-C, and the small amount of P450-B1 mRNA in 91-C was significantly larger in size than that in 91-R. The P450-B1 gene in 91-R was structurally different from that in 91-C but was not amplified. The P450-B1 gene in 91-C contained a solitary long terminal repeat of transposable element 17.6 in its 3' untranslated region. It was absent in the P450-B1 gene of 91-R. On the basis of features of the long terminal repeat and its location in the gene of the susceptible fly, we propose that a posttranscriptional mechanism involving mRNA stability could be involved in regulating P450-B1 gene expression.
Waters
L C
LC
Biology Division, Oak Ridge National Laboratory, TN 37831-8077.
Zelhof
A C
AC
Shaw
B J
BJ
Ch'ang
L Y
LY
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004251:DNA Transposable Elements; D004331:Drosophila melanogaster / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D007305:Insecticide Resistance; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D014158:Transcription, Genetic
D004251:DNA Transposable Elements; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System