INSTABILITY OF MESSENGER AND RIBOSOMAL RNA IN A GLUE-PROTEIN MUTANT OF Bombyx mori

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Silkworm (Bombyx mori) eggs require glue proteins secreted by mucous glands for adhesion.
• A dominant gene mutation, no glue (Ng), results in nonadhesive eggs and reduced glue protein synthesis.

Purpose of the Study:

• To investigate the molecular mechanisms underlying reduced glue protein synthesis in Ng mutant silkworms.
• To determine the role of RNA metabolism in the mucous glands of normal and mutant silkworms.

Main Methods:

• Comparative analysis of mRNA and rRNA degradation in mucous glands of Ng mutant and normal silkworms during development.
• Assessment of RNA degradation inhibition using actinomycin D in Ng mutant silkworms.

Main Results:

• Ng mutant silkworms exhibit rapid degradation of mRNA and rRNA in mucous glands.
• Normal silkworms show increased RNA content correlating with peak glue protein synthesis.
• Actinomycin D treatment inhibited RNA degradation in Ng mutant mucous glands.

Conclusions:

• The Ng gene likely codes for a controller RNA that mediates RNA instability in the mucous glands of Ng pupae.
• RNA instability is a key factor contributing to the low glue protein synthesis capacity in Ng mutant silkworms.