Sites of Fibroin Formation in the Silk Gland in Bombyx mori

Abstract

IT has been clear from micro-autoradiography that glycine, one of the constituents of silk fibroin, is incorporated into the posterior division of the silk gland in the silkworm¹, though the intracellular organelles on the fibroin formation and the intracellular transport of newly synthesized fibroin are yet unknown. To determine whether or not both intracellular organelles, the rough endoplasmic reticulum and the Golgi region are responsible for fibroin formation in the silk gland of Bombyx, glycine labelled with tritium has been used for the demonstration of the supposed sites of fibroin formation in the glandular cell situated in the posterior division of the silk gland, and of intracellular transport of newly synthesized fibroin.