title: Yeast Rrp8p, a novel methyltransferase responsible for m1A 645 base modification of 25S rRNA.
abstract: Ribosomal RNA undergoes various modifications to optimize ribosomal structure and expand the topological potential of RNA. The most common nucleotide modifications in ribosomal RNA (rRNA) are pseudouridylations and 2'-O methylations (Nm), performed by H/ACA box snoRNAs and C/D box snoRNAs, respectively. Furthermore, rRNAs of both ribosomal subunits also contain various base modifications, which are catalysed by specific enzymes. These modifications cluster in highly conserved areas of the ribosome. Although most enzymes catalysing 18S rRNA base modifications have been identified, little is known about the 25S rRNA base modifications. The m(1)A modification at position 645 in Helix 25.1 is highly conserved in eukaryotes. Helix formation in this region of the 25S rRNA might be a prerequisite for a correct topological framework for 5.8S rRNA to interact with 25S rRNA. Surprisingly, we have identified ribosomal RNA processing protein 8 (Rrp8), a nucleolar Rossman-fold like methyltransferase, to carry out the m(1)A base modification at position 645, although Rrp8 was previously shown to be involved in A2 cleavage and 40S biogenesis. In addition, we were able to identify specific point mutations in Rrp8, which show that a reduced S-adenosyl-methionine binding influences the quality of the 60S subunit. This highlights the dual functionality of Rrp8 in the biogenesis of both subunits.
authors.affiliation: Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt/M, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Peifer
authors.forename: Sunny
authors.initials: S
authors.lastname: Sharma
authors.forename: Peter
authors.initials: P
authors.lastname: Watzinger
authors.forename: Stefanie
authors.initials: S
authors.lastname: Lamberth
authors.forename: Peter
authors.initials: P
authors.lastname: Kötter
authors.forename: Karl-Dieter
authors.initials: KD
authors.lastname: Entian
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000378:metabolism; D008745:Methylation; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011497:Protein O-Methyltransferase; D012335:RNA, Ribosomal / Q000737:chemistry / Q000378:metabolism*; D020718:Ribonucleoproteins, Small Nucleolar / Q000235:genetics / Q000378:metabolism; D054683:Ribosome Subunits, Large, Eukaryotic / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion
chemical_list: D009687:Nuclear Proteins; D012335:RNA, Ribosomal; D020718:Ribonucleoproteins, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; C065039:RNA, ribosomal, 25S; C073180:GAR1 protein, S cerevisiae; C008407:1-methyladenine; D012436:S-Adenosylmethionine; D008780:Methyltransferases; D011497:Protein O-Methyltransferase; C410601:RRP8 protein, S cerevisiae; D000225:Adenine