CONTROL OF SYNTHESIS OF RNA AND PROTEIN IN DIAPAUSING AND INJURED CECROPIA PUPAE

Area of Science:

• Developmental biology
• Molecular biology
• Insect physiology

Background:

• Injury to diapausing cecropia silkworm moth pupae triggers physiological responses.
• These responses include increased RNA and blood protein synthesis.
• A specific 'injury protein' is precociously synthesized upon injury.

Purpose of the Study:

• To investigate the role of RNA synthesis in injury-induced protein production.
• To determine the effect of Actinomycin D on specific protein synthesis pathways.
• To elucidate the regulatory mechanisms of gene expression in response to injury.

Main Methods:

• Inducing injury in diapausing cecropia silkworm moth pupae.
• Administering Actinomycin D at different concentrations (2 µg/g and 0.5 µg/g).
• Analyzing RNA and de novo blood protein synthesis, including 'injury protein'.

Main Results:

• Injury stimulates RNA and blood protein synthesis in all pupal tissues.
• Actinomycin D (2 µg/g) blocks both increased blood protein synthesis and 'injury protein' synthesis.
• Actinomycin D (0.5 µg/g) inhibits 'injury protein' synthesis but not other blood protein synthesis.

Conclusions:

• Low concentrations of Actinomycin D selectively inhibit the synthesis of new messenger RNAs.
• Existing messenger RNAs in production can continue synthesis at lower Actinomycin D concentrations.
• This suggests differential regulation of gene expression for specific proteins during injury response.