18S rRNA processing requires the RNA helicase-like protein Rrp3

• Published in: Nucleic acids research Vol. 24; no. 16; pp. 3201 - 3207
• Main Authors: O'Day, C.L, Chavanikamannil, F, Abelson, J
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 15.08.1996
• Subjects: Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - isolation & purification; Amino Acid Sequence; amino acid sequences; Base Sequence; cloning; Cloning, Molecular; complementary DNA; DEAD-box RNA Helicases; Enzyme Repression; genbank/p38712; Genes, Fungal; Genes, Lethal; Molecular Sequence Data; nucleotide sequences; Polymerase Chain Reaction; proteins; ribosomal RNA; RNA Helicases; RNA Nucleotidyltransferases - genetics; RNA Precursors - metabolism; RNA Processing, Post-Transcriptional; RNA, Ribosomal, 18S - biosynthesis; RNA-Binding Proteins - genetics; RNA-Binding Proteins - isolation & purification; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins; Sequence Homology; Transcription, Genetic
• ISSN: 0305-1048; 1362-4962; 1362-4962
• DOI: 10.1093/nar/24.16.3201

We report the identification of a new gene, RRP3 (rRNA processing), which is required for pre-rRNA processing. Rrp3 is a 60.9 kDa protein that is required for maturation of the 35S primary transcript of pre-rRNA and is required for cleavages leading to mature 18S RNA. RRP3 was identified in a PCR screen for DEAD box genes. DEAD box genes are part of a large family of proteins homologous to the eukaryotic transcription factor eIF-4a. Most of these proteins are RNA-dependent ATPases and some of them have RNA helicase activity. This is the third yeast DEAD box protein that has been shown to be involved in rRNA assembly, but the only one required for the processing of 18S RNA. Mutants of the two other putative helicases, Spb4 and DrsI, both show processing defects in 25S rRNA maturation. In strains where Rrp3 is depleted, 35S precursor RNA is improperly processed. Cleavage normally occurs at sites A0, A1 and A2, but in the Rrp3 depletion stain cleavage occurs between A2 and B1. Rrp3 has been purified to homogeneity and has a weak RNA-dependent ATPase activity which is not specific for rRNA.