A palmitoyltransferase Approximated gene Bm-app regulates wing development in Bombyx mori

Area of Science:

• Genetics
• Developmental Biology
• Molecular Biology

Background:

• The silkworm (Bombyx mori) is a key model organism in lepidopteran research, with numerous identified natural mutants.
• The molecular underpinnings of most silkworm mutations remain largely uncharacterized, hindering a deeper understanding of their genetic basis.

Purpose of the Study:

• To identify the gene responsible for the minute wing (mw) mutation in Bombyx mori.
• To elucidate the molecular mechanism by which this gene regulates wing development.

Main Methods:

• Comparative gene expression analysis between wild-type and mutant silkworms.
• Identification and characterization of mutations in the Bm-app gene promoter region.
• Dual luciferase assays to assess promoter activity.
• CRISPR/Cas9-mediated gene depletion to validate gene function.

Main Results:

• The Bm-app gene was identified as the cause of the minute wing (mw) mutation.
• A 10 bp insertion in the Bm-app promoter region significantly reduced its activity in the mw mutant.
• Depletion of Bm-app using CRISPR/Cas9 resulted in wing defects similar to the mw phenotype.
• Bm-app encodes a palmitoyltransferase essential for cell mitosis and growth during wing development.

Conclusions:

• Bm-app is essential for normal wing development in Bombyx mori.
• The identified mutation in the Bm-app promoter disrupts gene expression, leading to the mw phenotype.
• Bm-app's role in palmitoylation suggests its importance in cell proliferation and potentially links it to the Hippo signaling pathway in silkworm wing development.