RRC ID 22738
著者 Fujii T, Abe H, Kawamoto M, Katsuma S, Banno Y, Shimada T.
タイトル Albino (al) is a tetrahydrobiopterin (BH4)-deficient mutant of the silkworm Bombyx mori.
ジャーナル Insect Biochem Mol Biol
Abstract Albino (al) is a lethal mutant of Bombyx mori that exhibits a colourless cuticle after the first ecdysis and dies without feeding on mulberry. Previous studies have indicated that sclerotisation was insufficient because of defective phenylalanine and tyrosine metabolism in albino larvae. However, the genetic mechanism underlying the albino phenotype has not been determined. Dopamine plays a central role in insect cuticle colouration and sclerotisation. The pathway for dopamine biosynthesis from phenylalanine involves phenylalanine hydroxylase (PAH; EC 1.14.16.1) and tyrosine hydroxylase (TH; EC 1.14.16.2). Tetrahydrobiopterin (BH4) is an essential cofactor of aromatic amino acid hydroxylases, including PAH and TH. Thus, BH4 is indispensable for cuticle colouration and sclerotisation. Here we report on identifying mutations in the gene that encodes for the Bombyx homolog of 6-pyruvoyl-tetrahydropterin synthase (PTS) which is involved in the biosynthesis of BH4, in 2 strains with different al alleles. In strain a60 (al), a transposable element was inserted in exon 2 of BmPTS. In strain a61 (al²), an 11-bp deletion was identified in the exon 2 region of BmPTS. After oral administration of BH4 to the al² larvae, the survival rate was effectively increased and the larval integument was pigmented. These results indicated that BmPTS was responsible for the albino mutants of B. mori. We conclude that (i) a mutation in BmPTS leads to an insufficient supply of BH4 and results in defective dopamine biosynthesis and (ii) lack of dopamine results in cuticle colouration and sclerotisation failure. Lemon (lem) is a BH4-deficient mutant. It has been reported that de novo synthesis of zygotic BH4 was indispensable for viability of the embryo in eggs laid by lem (lem/lem¹) females. We found that lem/lem, al²/al² larvae produced by lem (lem/lem) females were viable during the first instar stage, suggesting that al²/al² embryo could synthesis BH4 by using maternally transmitted BmPTS.
巻・号 43(7)
ページ 594-600
公開日 2013-7-1
DOI 10.1016/j.ibmb.2013.03.009
PII S0965-1748(13)00052-0
解説 al(アルビノ)の原因遺伝子はBmPTSである。BmPTSは、6‐ピルボイルテトラヒドロプテリン合成酵素をコードする。a60系統(al/al)では、BmPTSのエクソン2に約4 kbの転移因子が挿入されている。a61系統(al2/al2)ではエクソン2に11塩基の欠失が認められる。al2/al2幼虫の致死はBH4の経口投与で救済される。
PMID 23567588
MeSH Animals Biopterin / analogs & derivatives* Biopterin / deficiency Biopterin / genetics Bombyx / enzymology* Bombyx / genetics Bombyx / growth & development Dopamine / metabolism Female Insect Proteins / genetics* Insect Proteins / metabolism Larva / genetics Larva / growth & development Larva / metabolism Male Mutation* Phenylalanine / metabolism Phosphorus-Oxygen Lyases / genetics Phosphorus-Oxygen Lyases / metabolism
IF 3.827
引用数 14
WOS 分野 ENTOMOLOGY BIOCHEMISTRY & MOLECULAR BIOLOGY
リソース情報
カイコ a60 a61 l80