Starvation changes the pre-rRNA accumulations in Caenorhabditis elegans

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Ribosome biogenesis is crucial for cell growth but energetically expensive.
• Under starvation, cells adapt ribosome biogenesis to conserve energy.
• The specific mechanisms of pre-rRNA processing in C. elegans are not fully understood.

Purpose of the Study:

• To elucidate the precursor rRNA (pre-rRNA) processing pathway in Caenorhabditis elegans.
• To investigate the impact of short-term starvation on rRNA maturation in C. elegans.
• To identify specific pre-rRNA species affected by starvation and their localization within the nucleolus.

Main Methods:

• Northern blot analysis was used to detect and quantify pre-rRNA species.
• Localization studies within the nucleolus were performed.
• Nutritional replenishment experiments were conducted to observe recovery patterns.

Main Results:

• The cleavage site in internal transcribed spacer 2 was identified, generating 5.8S rRNA and 26S rRNA precursors.
• Starvation led to decreased levels of large subunit pre-rRNA (pre-rRNA c'1/27SA2) and increased levels of small subunit pre-rRNA (pre-rRNA d).
• Pre-rRNAs accumulated in the nucleolar center, while the FIB-1 factor localized to the periphery; these patterns reversed upon nutrient refeeding.

Conclusions:

• The study defines critical steps in C. elegans pre-rRNA processing.
• Nutritional status significantly impacts rRNA synthesis and maturation dynamics.
• Cellular responses to starvation involve coordinated changes in pre-rRNA processing and nucleolar organization, which are reversible.