Yellow-e determines the color pattern of larval head and tail spots of the silkworm Bombyx mori.
Yellow proteins form a large family in insects. In Drosophila melanogaster, there are 14 yellow genes in the genome. Previous studies have shown that the yellow gene is necessary for normal pigmentation; however, the roles of other yellow genes in body coloration are not known. Here, we provide the first evidence that yellow-e is required for normal body color pattern in insect larvae. In two mutant strains, bts and its allele bts2, of the silkworm Bombyx mori, the larval head cuticle and anal plates are reddish brown instead of the white color found in the wild type. Positional cloning revealed that deletions in the Bombyx homolog of the Drosophila yellow-e gene (Bmyellow-e) were responsible for the bts/bts2 phenotype. Bmyellow-e mRNA was strongly expressed in the trachea, testis, and integument, and expression markedly increased at the molting stages. This profile is quite similar to that of Bmyellow, a regulator of neonatal body color and body markings in Bombyx. Quantitative reverse transcription-PCR analysis showed that Bmyellow-e mRNA was heavily expressed in the integument of the head and tail in which the bts phenotype is observed. The present results suggest that Yellow-e plays a crucial role in the pigmentation process of lepidopteran larvae.
Ito
Katsuhiko
K
Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
Katsuma
Susumu
S
Yamamoto
Kimiko
K
Kadono-Okuda
Keiko
K
Mita
Kazuei
K
Shimada
Toru
T
D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000196:embryology / Q000235:genetics*; D004331:Drosophila melanogaster; D006257:Head / Q000196:embryology; D007301:Insect Hormones / Q000096:biosynthesis / Q000235:genetics*; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010858:Pigmentation / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013623:Tail / Q000196:embryology
D007301:Insect Hormones; D019476:Insect Proteins; D012333:RNA, Messenger