Piedrafita A C, Martínez-Ramírez A C, Silva F J
Departament de Genètica, Universitat de València, Spain.
Insect Biochem Mol Biol. 1994 Jun;24(6):581-8. doi: 10.1016/0965-1748(94)90094-9.
Around 50 min after adult ecdysis, a significant increase in DOPA content is observed in Drosophila melanogaster. This increase, which is followed by increases of other catecholamine sclerotizing precursors, parallels the visually observable pigmentation and hardening of the adult cuticle. Since this DOPA concentration developmental profile is correlated with cuticle formation, we have analyzed the involvement of aromatic amino acid hydroxylases in this process by determining the same profile in mutant strains affecting these hydroxylations, either directly (defects in the genes coding for these hydroxylases), or indirectly (defects in genes involved in the biosynthesis of the essential pterin cofactor, tetrahydrobiopterin). The altered profiles of the pterin biosynthesis defective strains Pu2/SM1 and cn prc4/cn prm2b showed that some pterin is required for these metabolic changes. Meanwhile the altered profiles of the Hnr3 and ple/TM3 strains directly implicate the phenylalanine and tyrosine hydroxylase enzymes. An analysis of the phenylalanine hydroxylase protein presence during the period of the first 3 h post adult ecdysis in thorax plus abdomen extracts has shown that although the protein is present during the complete developmental period, no changes in the cross reacting material amounts are observed.
在成年果蝇蜕皮后约50分钟，其体内多巴（DOPA）含量显著增加。这一增加之后，其他儿茶酚胺硬化前体也随之增加，这与成虫表皮在视觉上可观察到的色素沉着和硬化过程同步。由于这种多巴浓度的发育变化曲线与表皮形成相关，我们通过在影响这些羟化反应的突变菌株中测定相同的变化曲线，来分析芳香族氨基酸羟化酶在这一过程中的作用，这些突变菌株要么直接（编码这些羟化酶的基因存在缺陷），要么间接（参与必需蝶呤辅因子四氢生物蝶呤生物合成的基因存在缺陷）影响羟化反应。蝶呤生物合成缺陷菌株Pu2/SM1和cn prc4/cn prm2b的变化曲线表明，这些代谢变化需要一些蝶呤。同时，Hnr3和ple/TM3菌株的变化曲线直接表明苯丙氨酸羟化酶和酪氨酸羟化酶起了作用。对成虫蜕皮后最初3小时内胸腹部提取物中苯丙氨酸羟化酶蛋白存在情况的分析表明，尽管该蛋白在整个发育期间都存在，但未观察到交叉反应物质数量的变化。
