A cytochrome P450 terpenoid hydroxylase linked to the suppression of insect juvenile hormone synthesis.
A cytochrome P450 terpenoid hydroxylase linked to the suppression of insect juvenile hormone synthesis.
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DOI：
10.1073/pnas.95.22.12884
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发表时间：
1998-10
影响因子：
11.1
通讯作者：
Tara D. Sutherland;G. C. Unnithan;John F. Andersen;Philip H. Evans;Marat B. Murataliev;Lajos Szabo
中科院分区：
文献类型：
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作者：
Tara D. Sutherland;G. C. Unnithan;John F. Andersen;Philip H. Evans;Marat B. Murataliev;Lajos Szabo
从繁殖活跃的斑点双翅小蠊咽侧体（CA）cDNA文库中分离出编码细胞色素P450酶的cDNA。这种来自产生昆虫保幼激素（JH）的内分泌腺的P450与家族4的P450蛋白最密切相关，并被命名为CYP 4C 7。CYP 4C 7基因在CA中选择性表达;其信息在脂肪体、心体或脑中无法检测到，但在中肠和盲肠中发现痕量水平的表达。CA中的CYP 4C 7 mRNA的水平，通过核糖核酸酶保护测定，与腺体的活动周期。在成年女性，CYP 4C 7的表达增加后立即JH合成的高峰，达到最高值在第7天，产卵前。mRNA水平然后下降产卵后和怀孕期间。CYP 4C 7蛋白在大肠杆菌中作为C-末端His-标记的重组蛋白产生。在含有昆虫NADPH细胞色素P450还原酶、细胞色素b5和NADPH的复溶系统中，纯化的CYP 4C 7将（2 E，6 E）-法尼醇代谢为极性更强的产物，经GC-MS和NMR鉴定为（10 E）-12-羟基法尼醇。CYP 4C 7将JH III转化为12-反式羟基JH III，并代谢其他JH样倍半萜类化合物。倍半萜类化合物的这种ω-羟基化似乎是咽侧体中的代谢途径，其可能在生殖营养周期结束时抑制JH生物合成中发挥作用。
A cDNA encoding a cytochrome P450 enzyme was isolated from a cDNA library of the corpora allata (CA) from reproductively active Diploptera punctata cockroaches. This P450 from the endocrine glands that produce the insect juvenile hormone (JH) is most closely related to P450 proteins of family 4 and was named CYP4C7. The CYP4C7 gene is expressed selectively in the CA; its message could not be detected in the fat body, corpora cardiaca, or brain, but trace levels of expression were found in the midgut and caeca. The levels of CYP4C7 mRNA in the CA, measured by ribonuclease protection assays, were linked to the activity cycle of the glands. In adult females, CYP4C7 expression increased immediately after the peak of JH synthesis, reaching a maximum on day 7, just before oviposition. mRNA levels then declined after oviposition and during pregnancy. The CYP4C7 protein was produced in Escherichia coli as a C-terminal His-tagged recombinant protein. In a reconstituted system with insect NADPH cytochrome P450 reductase, cytochrome b5, and NADPH, the purified CYP4C7 metabolized (2E,6E)-farnesol to a more polar product that was identified by GC-MS and by NMR as (10E)-12-hydroxyfarnesol. CYP4C7 converted JH III to 12-trans-hydroxy JH III and metabolized other JH-like sesquiterpenoids as well. This omega-hydroxylation of sesquiterpenoids appears to be a metabolic pathway in the corpora allata that may play a role in the suppression of JH biosynthesis at the end of the gonotrophic cycle.