3'-End formation of transcripts from the yeast rRNA operon

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Ribosomal RNA (rRNA) synthesis and processing are fundamental to cellular function.
• Understanding the precise mechanisms of rRNA maturation is crucial for comprehending gene expression regulation.

Purpose of the Study:

• To identify the DNA sequences responsible for the 3'-end formation of Saccharomyces cerevisiae 26S rRNA.
• To investigate the relationship between the processing of different pre-rRNA molecules.

Main Methods:

• Deletion analysis of artificial rRNA minigenes in Saccharomyces cerevisiae.
• Analysis of rRNA transcripts in wild-type and rna 82.1 mutant yeast strains.
• Comparative sequence analysis of rRNA genes from different yeast species.

Main Results:

• A 110 bp fragment (-36 to +74) is necessary and sufficient for correct 3'-end processing of 26S rRNA and 37S pre-rRNA.
• The rna 82.1 mutation affects rRNA processing, indicating a common factor for 37S and 5S pre-rRNA maturation.
• Conserved sequence blocks in intergenic regions suggest roles in processing factor interaction.

Conclusions:

• A common endonuclease likely processes both 37S and 5S pre-rRNAs.
• Specific DNA sequences within the rRNA gene are critical for accurate transcript termination and processing.
• A potential RNA polymerase I terminator site was identified downstream of the rRNA coding region.