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Updated: Feb 10, 2026

Author Spotlight: Advancing Gene Silencing Research in Silkworms with dsRNA Delivery Through Feeding Chitosan Nanoparticles
Published on: October 4, 2024
Unique sex determination system in the silkworm, Bombyx mori: current status and beyond
Susumu Katsuma1, Takashi Kiuchi1, Munetaka Kawamoto1
1Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo.
Abstract:
The silkworm Bombyx mori has been used for silk production for over 5,000 years. In addition to its contribution to sericulture, B. mori has played an important role in the field of genetics. Classical genetic studies revealed that a gene(s) with a strong feminizing activity is located on the W chromosome, but this W-linked feminizing gene, called Feminizer (Fem), had not been cloned despite more than 80 years of study. In 2014, we discovered that Fem is a precursor of a single W chromosome-derived PIWI-interacting RNA (piRNA). Fem-derived piRNA binds to PIWI protein, and this complex then cleaves the mRNA of the Z-linked Masculinizer (Masc) gene, which encodes a protein required for both masculinization and dosage compensation. These findings showed that the piRNA-mediated interaction between the two sex chromosomes is the primary signal for the sex determination cascade in B. mori. In this review, we summarize the history, current status, and perspective of studies on sex determination and related topics in B. mori.
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