摘要
Phenylalanine hydroxylase is assumed to be a key enzyme in drosopterin metabolism, but direct in vivo evidence to support this hypothesis is still absent.In the present study, we found a new natural reces-sive purple eye mutant of Drosophila melanogaster, Hnbp, which was a 45-nt insertion mutant in the second exon of Henna.The insertion resulted in a predicted protein with 15 additional amino acids as compared to the wild-type protein.Further analysis of protein structure showed that the predicted mutant protein probably had two more β-sheets, which may cause instability of two α-helices near the catalytic centre of the enzyme in the Biopterin-Hydroxyl binding domain.Hnbp mutant showed eye color defect with decrease of mRNA level, as well as drosopterin content reduction.The drosopterin defect could be fully rescued by expression of wild type Henna in the Hnbp background by GMR-GAL4 UAS-Henna/UAS-Henna:Hnbp/Hnbp transgenic line.All taken together, it can be concluded that the mu-tation in Henna is responsible for drosopterin reduction in mutant Hnbp, which provides key in vivo evidence to support the hypothesis that Henna is involved in drosopterin synthesis.
Phenylalanine hydroxylase is assumed to be a key enzyme in drosopterin metabolism, but direct in vivo evidence to support this hypothesis is still absent.In the present study, we found a new natural reces-sive purple eye mutant of Drosophila melanogaster, Hnbp, which was a 45-nt insertion mutant in the second exon of Henna.The insertion resulted in a predicted protein with 15 additional amino acids as compared to the wild-type protein.Further analysis of protein structure showed that the predicted mutant protein probably had two more β-sheets, which may cause instability of two α-helices near the catalytic centre of the enzyme in the Biopterin-Hydroxyl binding domain.Hnbp mutant showed eye color defect with decrease of mRNA level, as well as drosopterin content reduction.The drosopterin defect could be fully rescued by expression of wild type Henna in the Hnbp background by GMR-GAL4 UAS-Henna/UAS-Henna:Hnbp/Hnbp transgenic line.All taken together, it can be concluded that the mu-tation in Henna is responsible for drosopterin reduction in mutant Hnbp, which provides key in vivo evidence to support the hypothesis that Henna is involved in drosopterin synthesis.
基金
the State Major Basic Research Development Program (Grant No. 2006CB102100)
National Natural Science Foundation of China (Grant No. 30771535)
