Liu N, Scott J G
Department of Entomology, Cornell University, Ithaca, New York 14853-0901, USA.
Biochem Genet. 1996 Apr;34(3-4):133-48. doi: 10.1007/BF02396246.
To understand better the biochemical genetics of cytochrome P450 monooxygenase-mediated insecticide resistance, we examined the microsomal monooxygenases in insecticide-susceptible (aabys) and pyrethroid-resistant (LPR) house fly strains, as well as 15 house fly lines derived from crosses of LPR and aabys. In comparison to the aabys strain, LPR had higher levels of total cytochromes P450, cytochrome b5, P450 reductase, CYP6D1, and three P450 monooxygenase activities: 7-ethoxycoumarin O-deethylase (ECOD), methoxyresorufin O-demethylase (MROD), and aromatic hydrocarbon hydroxylase (AHH). The elevated levels of cytochrome b5 were linked to factors on autosomes 1 and 2. This is similar to previous reports on monooxygenase-mediated resistance and is consistent with the idea that elevated cytochrome b5 levels are involved in monooxygenase-mediated resistance in the LPR strain. Linkage of the elevated P450 reductase is different from that of monooxygenase-mediated resistance. Strains having high levels of CYP6D1 (i.e., like LPR) had high levels of P450 reductase, while strains having intermediate levels of CYP6D1 also had high levels of reductase. Therefore, there is no clear evidence that the elevated P450 reductase in the LPR strain is required for the increased monooxygenase activity. Overexpression of total cytochromes P450, CYP6D1 (mRNA and protein), and CYP6D1-mediated monooxygenase activities (MROD and AHH) in LPR microsomes was linked to a combination of factors on autosomes 1 and 2. This demonstrates that increased expression of CYP6D1 in the LPR strain is both cis regulated by a factor(s) on autosome 1 and trans regulated by a factor(s) on autosome 2. The correlation between the overexpression of CYP6D1 mRNA and protein suggests that CYP6D1 expression is regulated transcriptionally. Monooxygenase-mediated resistance in LPR is controlled by factors on autosomes 1 and 2, which supports previous claims that CYP6D1 is responsible for monooxygenase-mediated resistance in the LPR strain.
为了更好地理解细胞色素P450单加氧酶介导的杀虫剂抗性的生化遗传学，我们检测了对杀虫剂敏感的（aabys）和对拟除虫菊酯抗性的（LPR）家蝇品系以及由LPR和aabys杂交产生的15个家蝇品系中的微粒体单加氧酶。与aabys品系相比，LPR的总细胞色素P450、细胞色素b5、P450还原酶、CYP6D1以及三种P450单加氧酶活性水平更高：7-乙氧基香豆素O-脱乙基酶（ECOD）、甲氧基试卤灵O-脱甲基酶（MROD）和芳烃羟化酶（AHH）。细胞色素b5水平的升高与常染色体1和2上的因子有关。这与之前关于单加氧酶介导的抗性的报道相似，并且与细胞色素b5水平升高参与LPR品系中单加氧酶介导的抗性这一观点一致。P450还原酶升高的连锁关系与单加氧酶介导的抗性不同。具有高水平CYP6D1（即像LPR）的品系具有高水平的P450还原酶，而具有中等水平CYP6D1的品系也具有高水平还原酶。因此，没有明确证据表明LPR品系中升高的P450还原酶是单加氧酶活性增加所必需的。LPR微粒体中总细胞色素P450、CYP6D1（mRNA和蛋白质）以及CYP6D1介导的单加氧酶活性（MROD和AHH）的过表达与常染色体1和2上的多种因子组合有关。这表明LPR品系中CYP6D1表达的增加既受常染色体1上一个或多个因子的顺式调控，也受常染色体2上一个或多个因子的反式调控。CYP6D1 mRNA和蛋白质过表达之间的相关性表明CYP6D1表达受转录调控。LPR中单加氧酶介导的抗性受常染色体1和2上的因子控制，这支持了之前关于CYP6D1负责LPR品系中单加氧酶介导的抗性的说法。
