Carotenoid silk coloration is controlled by a carotenoid-binding protein, a product of the Yellow blood gene

Takashi Sakudoh, Hideki Sezutsu, Takeharu Nakashima, Isao Kobayashi, Hirofumi Fujimoto, Keiro Uchino, Yutaka Banno, Hidetoshi Iwano, Hideaki Maekawa, Toshiki Tamura, Hiroshi Kataoka, Kozo Tsuchida

Research output: Contribution to journalArticlepeer-review

128 Citations (Scopus)


Mechanisms for the uptake and transport of carotenoids, essential nutrients for humans, are not well understood in any animal system. The Y (Yellow blood) gene, a critical cocoon color determinant in the silkworm Bombyx mori, controls the uptake of carotenoids into the intestinal mucosa and the silk gland. Here we provide evidence that the Y gene corresponds to the intracellular carotenoid-binding protein (CBP) gene. In the Y recessive strain, the absence of an exon, likely due to an incorrect mRNA splicing caused by a transposon-associated genomic deletion, generates a nonfunctional CBP mRNA, resulting in colorless hemolymph and white cocoons. Enhancement of carotenoid uptake and coloration of the white cocoon was achieved by germ-line transformation with the CBP gene. This study demonstrates the existence of a genetically facilitated intracellular process beyond passive diffusion for carotenoid uptake in the animal phyla, and paves the way for modulating silk color and lipid content through genetic engineering.

Original languageEnglish
Pages (from-to)8941-8946
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number21
Publication statusPublished - May 22 2007

All Science Journal Classification (ASJC) codes

  • General


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