摘要
Dopamine is a precursor for melanin synthesis. Arylalkylamine N-acetyltransferase(AANAT) is involved in the melatonin formation in insects because it could catalyze the transformation from dopamine to dopamine-N-acetyldopamine. In this study, we identified a new AANAT gene in the silkworm(Bombyx mori) and assessed its role in the silkworm. The c DNA of this gene encodes 233 amino acids that shares 57 % amino acid identity with the Bm-i AANAT protein. We thus refer to this gene as Bm-i AANAT2. To investigate the role of Bm-i AANAT2, we constructed a transgenic interference system using a 3xp3 promoter to suppress the expression of Bm-i AANAT2 in the silkworm. We observed that melanin deposition occurs in the head and integument in transgenic lines. To verify the melanism pattern, dopamine content and the enzyme activity of AANAT were determined by high-performance liquid chromatography(HPLC). We found that an increase in dopamine levels affects melanism patterns on the heads of transgenic B. mori. A reduction in the enzyme activity of AANAT leads to changes in dopamine levels. We analyzed the expression of the Bm-i AANAT2 genes by q PCR and found that the expression of Bm-i AANAT2 gene is significantly lower in transgenic lines. Our results lead us to conclude that Bm-i AANAT2 is a new arylalkylamine N-acetyl-transferase gene in the silkworm and is involved in the metabolism of the dopamine to avoid the generation of melanin.
Dopamine is a precursor for melanin synthesis. Arylalkylamine N-acetyltransferase(AANAT) is involved in the melatonin formation in insects because it could catalyze the transformation from dopamine to dopamine-N-acetyldopamine. In this study, we identified a new AANAT gene in the silkworm(Bombyx mori) and assessed its role in the silkworm. The c DNA of this gene encodes 233 amino acids that shares 57 % amino acid identity with the Bm-i AANAT protein. We thus refer to this gene as Bm-i AANAT2. To investigate the role of Bm-i AANAT2, we constructed a transgenic interference system using a 3xp3 promoter to suppress the expression of Bm-i AANAT2 in the silkworm. We observed that melanin deposition occurs in the head and integument in transgenic lines. To verify the melanism pattern, dopamine content and the enzyme activity of AANAT were determined by high-performance liquid chromatography(HPLC). We found that an increase in dopamine levels affects melanism patterns on the heads of transgenic B. mori. A reduction in the enzyme activity of AANAT leads to changes in dopamine levels. We analyzed the expression of the Bm-i AANAT2 genes by q PCR and found that the expression of Bm-i AANAT2 gene is significantly lower in transgenic lines. Our results lead us to conclude that Bm-i AANAT2 is a new arylalkylamine N-acetyl-transferase gene in the silkworm and is involved in the metabolism of the dopamine to avoid the generation of melanin.
引文